[Federal Register Volume 68, Number 174 (Tuesday, September 9, 2003)]
[Proposed Rules]
[Pages 53083-53101]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 03-22860]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
RIN 1018-AI45
Endangered and Threatened Wildlife and Plants; Withdrawal of the
Proposed Rule to List the Mountain Plover as Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule; withdrawal.
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SUMMARY: We, the Fish and Wildlife Service (Service), determine that
the action of listing the mountain plover (Charadrius montanus) as
threatened, pursuant to the Endangered Species Act of 1973, as amended
(Act), is not warranted, and we consequently withdraw our proposed rule
and our proposed special rule. We make this determination because
threats to the species as identified in the proposed rule are not as
significant as earlier believed, and current available data do not
indicate that the threats to the species and its habitat, as analyzed
under the five listing factors described in section 4(a)(1) of the Act,
are likely to endanger the species in the foreseeable future throughout
all or a significant portion of its range.
ADDRESSES: The supporting documentation for this rulemaking is
available for public inspection, by appointment, during normal business
hours, at the U.S. Fish and Wildlife Service Field Office, 764 Horizon
Drive, Building B, Grand Junction, Colorado 81506-3946, telephone; 970-
243-2778, facsimile 970-245-6933, or e-mail al_pfister@fws.gov.
Pertinent information also is available at the Web site http://
www.r6.fws.gov/mtnplover/.
FOR FURTHER INFORMATION CONTACT: Allan Pfister, Assistant Field
Supervisor, Grand Junction, Colorado (see ADDRESSES), telephone 970-
243-2778; facsimile 970-245-6933.
SUPPLEMENTARY INFORMATION:
Background
The mountain plover (Charadrius montanus) is a small bird averaging
21 centimeters (8 inches) in body length and is similar in size and
appearance to a killdeer (Charadrius vociferus). It is light brown
above with a lighter colored breast, but lacks the contrasting dark
breastbelt common to most other plovers, including the killdeer.
Mountain plovers are insectivores; beetles, grasshoppers, crickets, and
ants are its principal food items (Stoner 1941, Baldwin 1971, Rosenberg
et al. 1991, Knopf 1998).
The mountain plover is associated with shortgrass and shrub-steppe
landscapes throughout its breeding and wintering range. Historically,
on the breeding range, the plover occurred on nearly denuded prairie
dog colonies (Knowles et al. 1982, Olson-Edge and Edge 1987) and in
areas of major bison concentrations where vegetation was clipped short
(Knopf 1997). Currently, the mountain plover also is found on human-
made landscapes (e.g., sod farms and cultivated fields) that may mimic
their natural habitat associations, and on other sites with little
vegetative cover (e.g., alkali flats). As mountain plovers are usually
associated with sites that are modified by grazing and digging mammals
(kangaroo rat (Dipodomys sp.) precincts and California ground squirrel
(Spermophilus beecheyi) colonies on wintering grounds in California, as
well as prairie dog colonies on the breeding grounds), Knopf and Miller
(1994) suggested classifying the mountain plover as a species more
closely associated with disturbed prairie sites, rather than pristine
prairie landscapes.
Mountain plovers nest in the Rocky Mountain and Great Plains States
from Montana south to Nuevo Leon, Mexico. Most mountain plovers breed
in Montana, Wyoming, and Colorado, with substantially fewer breeding
birds occurring in Arizona, Kansas, Nebraska, New Mexico, Oklahoma,
Texas, and Utah. Breeding was confirmed in 1999 in Mexico on a Mexican
prairie dog (Cynomys mexicanus) colony in the State of Nuevo Leon
(Desmond and Ramirez 2002). Nesting habitat in Canada is restricted to
southeastern Alberta and southwestern Saskatchewan. Nesting has not
been documented in Canada since 1990.
Breeding adults, nests, and chicks have been observed on cultivated
lands in Colorado, Kansas, Nebraska, Oklahoma, and Wyoming (Shackford
and Leslie 1995; Shackford et al. 1999; V. Dreitz, Colorado Natural
Heritage Program, in litt. 2003; Young and Good 2000). The majority of
mountain plovers winter in California, where they are found mostly on
cultivated fields. However, they also can be found on grasslands or
landscapes resembling grasslands (Edson and Hunting 1999, Knopf and
Rupert 1995, Wunder and Knopf 2003). Wintering mountain plovers also
are reported in Arizona, Texas, and Mexico, but fewer have been
documented at these locations than in California.
Historically, the mountain plover has been found in a variety of
habitats during winter, including grasslands and agricultural fields in
California (Belding 1879 in Grinnell et al. 1918; Tyler 1916; Grinnell
et al. 1918; Preston 1981 in Moore et al. 1990; Werschkull et al. 1984
in Moore et al. 1990). Irrigated farmlands--burned Bermuda grass fields
and grazed alfalfa fields--in the Imperial Valley of California, where
desert scrub has been converted to agriculture within the past 100
years, have become the predominant winter habitat for mountain plovers
(Wunder and Knopf 2003, AMEC Earth and Environmental 2003). There,
plovers move onto fields for short periods following harvest,
especially where the fields are turned over, burned, or grazed by
sheep. Insect availability, furrow depth, size of dirt clods, and the
vegetation of contiguous land parcels are believed to influence the
suitability of individual cultivated fields (E. Marquis-Brong, in litt.
1999). Therefore, while cultivated lands are abundant throughout the
Central and Imperial Valleys, not all of them are suitable wintering
habitat. Because annual climatic changes in the Central Valley can
greatly influence vegetative structure within a given year, mountain
plover observations at traditionally occupied sites decline in years
when abundant rainfall causes vegetation to become too tall (E.
Marquis-Brong, Bureau of Land Management (BLM), in litt. 1999).
Historically, breeding mountain plovers were reported as locally
rare to abundant, and widely distributed in the Great Plains region
from Canada south
[[Page 53084]]
to Texas (Coues 1878, Knight 1902, McCafferty 1930, Bailey and Neidrach
1965). Knopf (1996b) estimated the North American mountain plover
population to be between 8,000 to 10,000 birds. His estimate is based
on a 1994 count of mountain plovers on their winter habitat in
California. Applying the same assumptions using the more recent 1998-
2002 winter counts ranging from 1,372 to 4,037 individuals would yield
an estimate ranging from 5,000 to 11,000 (Hunting et al., 2001; Shuford
et al. 2000; Wunder and Knopf 2003, S. Myers, pers. comm. 2002). The
search efforts among years are not comparable, but represent the best
available information. We believe the estimates provided are a
reasonable approximation of mountain plover total abundance, given
recent survey efforts directed at mountain plovers on their winter
habitat, the dedicated efforts to locate them in California's Central
and Imperial valleys, and their winter flocking behavior that enhances
detection.
As discussed by Knopf (1996b), the continental breeding range of
the mountain plover has been reduced from its historical extent,
especially in the eastern portion of the range. The mountain plover was
formerly common in western and central Kansas (Goss 1891), and reported
as numerous between Fort Supply, Oklahoma, and Dodge City, Kansas
(McCauley 1877). The species was historically numerous in Colorado
(Bailey and Niedrach 1965) and Wyoming (Knight 1902). Lower numbers of
mountain plovers formerly occupied western South Dakota (South Dakota
Ornithologist's Union 1991) and Nebraska (Knopf 1996b), and there is
one known breeding reference from North Dakota (Roosevelt 1885). There
was a single report of breeding mountain plovers in northern Mexico in
1901 (Sanford et al. 1924), and breeding was confirmed in the State of
Nuevo Leon in 1999 (Desmond and Ramirez 2002).
Colorado--The Colorado Bird Atlas Partnership estimated a
population of 7,200 (range from 3,652 to 12,168) mountain plovers in
Colorado, with perhaps 22 percent of these in Weld County (H. Kingery,
in litt. 1997; Kingery 1998). However, this population estimate should
be considered a ``first approximation'' and used with caution (Kingery
1998). A more recent effort to estimate mountain plover abundance is
the Rocky Mountain Bird Observatory's estimate of 4,850 individual
mountain plovers in eastern Colorado (S. Gillihan, in litt. 2003).
Mountain plovers have been studied intensively in Weld County,
Colorado, from the late 1960s to the present. Graul and Webster (1976)
considered Weld County in northeastern Colorado the breeding stronghold
for the mountain plover, a conclusion widely referenced by subsequent
authors (e.g., Knopf and Rupert 1996). However, inventories completed
by the Colorado Bird Atlas Partnership from 1987 through 1995 found
mountain plovers more widely distributed than previously known in many
other eastern Colorado counties (Kingery 1998). Based on their
inventories, the Bird Atlas Partnership concluded that 75 percent of
Colorado's mountain plovers occurred south of Weld County (H. Kingery,
Colorado Bird Atlas Partnership, pers. comm. 1994, in litt. 1998).
Breeding mountain plovers also have been reported from southeastern
Colorado by others (Chase and Loeffler 1978; Nelson 1993; R. Estelle,
Colorado Bird Observatory, in litt. 1994; M. Scott, BLM, in litt. 2000;
K. Giesen, Colorado Division of Wildlife (CDOW), in litt. 2001). During
a 1996 inventory, Carter et al. (1996) concluded that mountain plovers
occur at very low densities in 10 eastern Colorado counties, and are
most numerous in Kiowa and Park Counties. Mountain plovers also have
been seen in Moffat County in northwestern Colorado (Behrends and
Atkinson 2000). The Colorado Natural Heritage Program conducted
mountain plover surveys in Park County in central Colorado from 1994
through 2002, and currently estimate 2,300 mountain plovers at this
location (Pague and Pague 1994, Sherman et al. 1996, Hanson 1997,
Granau and Wunder 2001, Wunder et al. in prep.). South Park appears to
currently be the most productive breeding location in Colorado, and
probably throughout the entire breeding range. This is clearly the
largest breeding population of mountain plovers in Colorado, and
perhaps throughout the breeding range.
In Weld County, 60 to 70 percent of the mountain plover habitat
occurs on the Pawnee National Grassland, a historically recognized
breeding stronghold (F. Knopf, in litt. 1991). Today, nearly all
mountain plovers have abandoned the Pawnee National Grassland. During
the late 1960s, Graul and Webster (1976) estimated about 69,000
hectares (171,000 acres) of good habitat on the Pawnee National
Grassland, with mountain plover densities of at least 10/
kilometer2 (26/mile2). Based on these estimates,
we calculate that at least 7,000 mountain plovers likely occupied the
Pawnee in the early 1970s. Knopf (in litt. 1991) estimated about 1,280
individuals in 1991, while presently the Grassland population is about
78 individuals (F. Knopf, pers. comm. 2002).
Graul (1973) hypothesized that mountain plover productivity on the
Pawnee is influenced by drought and its corresponding effects on food
supply. In 1995, the Pawnee received above-average spring rainfall
resulting in lush vegetation growth not suitable as mountain plover
nesting habitat. As a result, few birds were found there during the
breeding season; conditions continued through 1996 and 1997, with few
adult birds and very little reproduction observed through 2002 (Knopf
1996; F. Knopf, in litt. 2003).
Although mountain plovers nest on cultivated fields in southeast
Colorado and adjacent States, 1 study (Shackford et al.1999) found that
of 46 nests monitored on cultivated fields, 31 nests failed and the
fate of the remaining 15 nests was unknown. Of the 31 failed nests, 22
nests (48 percent of total nests) were destroyed by farm machinery.
Giesen (in litt. 2000) reported a higher nest success on agricultural
fields than on native rangeland. As a result of these conflicting
findings, research was initiated in five eastern Colorado counties to
better describe nest success and productivity, and the implications of
cultivated field nesting to mountain plover population recruitment (T.
McCoy, Colorado Natural Heritage Program, in litt. 2001). In 2001 and
2002 within the study area, nests on croplands numbered 45 and 85,
respectively, with the increase due to a 40 percent increase in area
surveyed (V. Dreitz, in litt. 2002). Nest success on cropland and
rangeland was equal in 2001, but was about 10 percent higher on range
in 2002 (V. Dreitz, in litt. 2002). Predation was the major cause of
nest failure on rangelands in 2001 and 2002. Predation and tillage
losses were the cause of nest failure on cropland, but the combined
losses on cropland were fewer than predation losses on rangeland in
either year.
Based on the data presented above, we estimate over 7,000 breeding
mountain plovers in Colorado.
Montana--The largest known number of breeding mountain plovers in
Montana is found on a large complex of black-tailed prairie dog
colonies in the contiguous Phillips and Blaine Counties (Knowles and
Knowles 2001, Dinsmore 2001). In Phillips County, nearly all mountain
plovers are found on active prairie dog colonies that also are grazed
by cattle (Dinsmore 2001).
Although Phillips and Blaine Counties contain a major breeding
concentration for the species (Knopf and
[[Page 53085]]
Miller 1994, Knowles and Knowles 2001, Dinsmore 2001), small numbers of
mountain plovers also breed on BLM lands in Valley County (Little
Beaver Creek), and on private land in Wheatland and Golden Valley
Counties near the Little Belt and Big Snowy Mountains (Knowles and
Knowles 1998). Surveys through 2003 also report mountain plovers in Big
Horn, Broadwater, Carbon, Fergus, Jefferson, Hill, Madison,
Musselshell, Petroleum, Rosebud, and Treasure Counties (L. Hanebury,
Service, pers. comm. 2003; Knowles and Knowles 1996, 1998; J. Grensten,
BLM, pers. comm. 1998).
The most recent information documents that the mountain plover
population in southern Phillips County increased from about 100
individuals in 1995, to 175 individuals in 2001 (Dinsmore 2001). In
2003, over 150 nests were found on the study site (Dinsmore, pers.
comm. 2003). This increase is likely due to the recovery of black-
tailed prairie dogs from a recent sylvatic plague epizootic. Mountain
plovers at the Fort Belknap Indian Reservation increased from 0 to 20
from 1993 to 1998 following an increase in black-tailed prairie dogs
and the introduction of bison grazing, and there may presently be as
many as 100 individuals, although the change may be due to more
rigorous inventory (Knowles and Knowles 2001; S. Dinsmore, pers. comm.
2003). Mountain plover densities on black-tailed prairie dog colonies
at the Charles M. Russell National Wildlife Refuge declined by more
than half from 1980 to 1996. Prairie dog numbers at Charles M. Russell
National Wildlife Refuge have increased since 1996, and plover numbers
have gone up slightly. Knowles and Knowles (2001) report that between
1992 and 2000 mountain plovers declined at their Central and
Southwestern study areas, but increased slightly at their Northeastern
study area.
Dinsmore (2001) concluded that mountain plovers in southern
Phillips County are entirely dependent on an active black-tailed
prairie dog population, and that the mountain plover abundance at his
study site will likely parallel the population trends of black-tailed
prairie dogs.
Knowles and Knowles (1996) estimated less than 2,000 mountain
plovers in Phillips and Blaine Counties, and less than 800 additional
individuals at the other occupied locations in the State. Based on his
6 years of research, Dinsmore (pers. comm. 2002) provided a rough
estimate of 700 mountain plovers throughout all of Phillips and Blaine
Counties, and noted that Knowles and Knowles (1996) estimate of 800
mountain plovers at other areas is reasonable. Therefore, we believe
the best information currently available indicates the total population
in Montana is approximately 1,500 mountain plovers (Knowles and Knowles
1996, Knowles and Knowles 1998, Dinsmore 2001, Dinsmore, pers. comm.
2002).
Wyoming--The mountain plover is classified as common in Wyoming,
with breeding known or suspected in 20 of 28 latitude/longitude blocks
(latilong blocks) occurring across the entire State (Wyoming Game and
Fish Department 1997). The latilong records reviewed included sightings
from 1969 to 1996, with the highest number of individual records
occurring in the Saratoga, Wapiti, Powell, Casper, Bill, and Laramie
blocks. Because the search effort among the blocks is not equal, the
number of records reported for each block is not a good indicator of
mountain plover abundance within each block. Further, while latilong
records may note evidence of breeding, they do not provide information
regarding nesting success. Based on these latilong records, the Wyoming
Game and Fish Department reports the mountain plover as common in the
State, but acknowledges that information is lacking to make any
estimate of total population or determine whether it is increasing,
stable, or declining (Oakleaf et al. 1996).
Additional inventories have been conducted in Wyoming that confirm
the presence of mountain plovers at many of the previously reported
locations. For example, surveys conducted in the Powder River Basin
(Campbell, Converse, Sheridan, Crook, and Weston Counties) in 2001, in
preparation for the Powder River Basin Oil and Gas Project, found 15
mountain plovers (Good et al. 2002, Keinath and Ehle 2002). Most of the
Powder River Basin is private land, and the surveys were conducted from
public roads only. Consequently, these surveys may not be a good
representation of mountain plover abundance in the Powder River Basin.
From 1992 to 2002, nesting was confirmed on the Thunder Basin National
Grassland (Thunder Basin) (within the Powder River Basin) in northeast
Wyoming in most years (Bartosiak 1992; M. Edwards, Forest Service, in
litt. 1994; T. Byer, in litt. 1997; T. Thompson, Forest Service, in
litt. 2003).
Knopf (in litt. 2001b) reported that mountain plovers may be more
common in Wyoming than previously believed, particularly in Carbon
County. In 1999 and 2000, a total of 159 and 105 mountain plover adults
were reported from Sweetwater and Carbon Counties, respectively, with
many fewer individuals reported from Albany, Bighorn, Fremont, Lincoln,
Natrona, Park, Sublette, and Washakie Counties (P. Deibert, in litt.
2002). Surveys near Lysite in Fremont County found 39 mountain plovers
on about 530 ha (1,300 ac) of suitable habitat (L. Hayden-Wing, Hayden-
Wing Associates, in litt. 2003). Surveys for mountain plovers in south-
central Wyoming in 2002 found a total of 50 adults and 11 nests
(Hayden-Wing Consultants 2002). As many as 51 mountain plovers likely
occurred on Foote Creek Rim in Carbon County in 1994, but the number
declined to 26 in 2002 (Young and Erickson 2003). Most plovers have
vacated habitat near the wind turbines and congregated on a prairie dog
colony on the northern end of the Rim (Young and Erickson 2003). Nine
nests were located on Foote Creek Rim in 2000 (Young and Good 2000).
The total number of mountain plovers observed on Thunder Basin
National Grasslands declined from 53 to 37 from 1993 to 2002, while the
area surveyed during this time quadrupled (T. Thompson, in litt 2003).
Black-tailed prairie dog colonies in the area were affected by a
significant plague event in 2001 and 2002. Mountain plovers on Thunder
Basin nest almost entirely on black-tailed prairie dog colonies
(Keinath and Ehlen 2002).
From 1979 to 2002, nesting was confirmed on and near the Antelope
Coal Mine in the southern Powder River Basin, and breeding densities
were reported to range from 0.9 to 2.4 birds/km2 (2.3 to
6.2/mi2) (Oelklaus 1989, Thunderbird Wildlife Consulting,
Inc. 2003). From 1982 to 1991, a total of 26 broods were reported on
mine permit areas, while only 6 broods have been reported on the same
permit areas from 1992 to 2002 (Thunderbird Wildlife Consulting, Inc.
2003). Parrish (1988) inventoried mountain plovers over an extensive
area of the southern Powder River Basin, and reported an overall
density of about 0.1 mountain plover/km2 (0.3/
mi2). Mountain plovers throughout the southern Powder River
Basin are generally thought to be widely scattered at low densities,
with a few areas of local concentrations (Oelklaus 1989). Inventories
from the Laramie Plains and Cheyenne Plains in the late 1950s report
densities ranging from 0.3 to 23.8 mountain plovers/km2 (0.9
to 61.9/mi2) (Laun 1957, Finzel 1964). Therefore, densities
reported from the southern Powder River Basin in the 1980s are less
than those reported from the Laramie and Cheyenne Plains in the 1950s,
but it is unknown whether the difference is due to a decline in
[[Page 53086]]
mountain plover abundance, inherent differences in habitat quality, or
both.
Knopf (in litt. 1991, 2001b) found mountain plovers on the Laramie
Plains, in the vicinity of Shirley Basin, on the Chapman Bench (Park
County) north of Cody, and on Mexican Flats (Carbon County) northwest
of Baggs. Specific surveys of Chapman Bench between 1988 and 1999 found
between 7 to 14 adult mountain plovers and some juveniles (P. Deibert,
pers. comm. 1999a).
Mountain plovers also breed in shrub-steppe habitat in southwest
Wyoming (Oakleaf et al. 1982). The BLM estimates 10 to 15 breeding
pairs in the Jack Morrow Hills north of Rock Springs in Sweetwater
County (L. Keith, BLM, pers. comm. 1999). Mountain plovers reported
from Morton Pass in Albany County have declined from about 30 in 1997
to about 5 in 2000 (Young and Erickson 2003).
Based on the best information available from Wyoming, mountain
plovers may number from 2,000 to 5,000 individuals (P. Deibert, pers.
comm. 2003; F. Knopf, in litt. 2003).
Nebraska--A nesting mountain plover was found in Kimball County in
western Nebraska in 1990 (F. Knopf, in litt. 1990), and two mountain
plover nests were found in a fallow field in the same vicinity in 1997
(W. Jobman, Service, in litt. 1997). Seventeen mountain plovers were
counted on 10 cultivated fields in western Nebraska in 1992 and 1995
(Shackford and Leslie 1995), and 1 nest was found in summer fallow in
Kimball County in 1999 (W. Jobman, in litt. 1999).
No mountain plovers were found in 2001, following inventories of 92
sites, including black-tailed prairie dogs colonies, in 8 western
Nebraska counties (K. Nelson, Nebraska Game and Parks Commission, in
litt. 2003). The lack of mountain plovers may have been due to the
survey occurring late in the breeding season. In 2002, a survey
occurred in Kimball County exclusively, which is dominated by dry land
wheat farming with very little shortgrass prairie. A total of 118
mountain plovers were found at the 66 locations surveyed, and all but 1
individual were in wheat fields. A total of 27 juvenile mountain
plovers also were seen, with most of these in tilled, fallow ground. We
have no information to assess trends in Nebraska, but the Nebraska Game
and Parks Commission is concerned about the bird's viability in the
State (K. Nelson, in litt. 2003).
New Mexico--Sager (1996) noted that the mountain plover was
reported as ``fairly common'' in New Mexico in 1928, and recognized
that the 152 mountain plovers he surveyed in 1995 would not likely be
construed as ``fairly common'' today. However, he cautioned that
mountain plovers may be more numerous than he reports because of their
difficulty in detection and clumped distribution. Sager (1996) also
reported that New Mexico is likely on the fringe of acceptable mountain
plover habitat. We are not aware of a total population estimate or
population trend for New Mexico.
Oklahoma--Historic records of mountain plovers east of Cimarron
County do not mention breeding behavior, so it is unclear whether the
mountain plovers reported were nesting or migrating to other locations.
Hence, both the historic and current distribution may be confined to
Cimarron County in the panhandle of Oklahoma. In Cimarron County during
the nesting seasons of 1986-1990, Shackford (1991) observed 15 mountain
plovers in native grassland and 10 in cultivated fields. Ten of the 15
birds observed in native grassland were on prairie dog colonies. The
few plovers found, combined with the discovery of one mountain plover
nest on a maize field, stimulated searches of cultivated fields in
Oklahoma in 1992, 1993, and 1994. Using approximately the same search
method and effort each year, 408, 428, and 108 individual mountain
plovers were found on cultivated fields in each of these years,
respectively, and up to 13 nests were found on the cultivated fields
from 1986 through 1995 (Shackford et al. 1999, Shackford and Leslie
1995). The plovers reported include both plovers seen during the
breeding season as well as mountain plovers in premigratory flocks. The
decline in 1994 is attributed to a decline in mountain plovers seen
during the nonbreeding season, not necessarily a decline in breeding
birds. No other surveys have been completed in Oklahoma, and estimates
of the total Statewide population have not been made (S. Harmon,
Service, pers. comm. 2002).
Kansas--Counts of breeding mountain plovers on cultivated lands in
western Kansas from 1992 through 1995 ranged from 52 (6 counties
searched) to 114 (4 counties searched) (Shackford and Leslie 1995).
Surveys of cultivated fields and rangelands within the boundary of the
Cimarron National Grassland (Cimarron) in Kansas also have been
conducted. Counts on the Cimarron in 1994, 1996, and 1997 ranged from 1
to 13, with most of the sightings on plowed fields (J. Chynoweth,
Forest Service, in litt. 1997).
Other Breeding Areas--In Utah, the only site known to have breeding
mountain plovers is in Duchesne County, south of Myton, in the Uinta
Basin. Counts of breeding mountain plovers in this area from 1992
through 2001 ranged from 6 to 29. From 1992 to 2001, broods were found
in all years except 1992, 1999, and 2001; six adults and no broods were
found in 2001; and no mountain plovers were seen in 2002 (T. Dabbs,
BLM, in litt. 1997; F. Knopf, in litt. 1999; B. Stroh, Forest Service,
pers. comm. 2002).
Three pairs of nesting mountain plovers were reported near Fort
Davis, Texas, in 1992 (K. Brian, Davis Mountain State Park, pers. comm.
1992). More recent breeding in Texas has not been reported due to lack
of access to private land (P. Horner, Texas Parks and Wildlife
Department, in litt. 1997).
From 1914 to the present, mountain plovers in Arizona have been
reported during the breeding season from Apache, LaPaz, Maricopa, and
Navajo Counties. A pair was found on Navajo Nation land near Winslow in
June 1995, and an adult incubating three eggs was found near
Springerville, Apache County, Arizona, in May 1996 (T. Cordery,
Service, pers. comm. 1998; D. Shroufe, Arizona Game and Fish
Department, in litt. 1999). In May 2002 breeding behavior was observed
in three birds west of Springerville, in Apache County (Ted Cordery,
BLM, pers. comm. 2003).
The most recent nesting record in Canada was one nest in
southeastern Alberta in 1989 (S. Jewell, Service, in litt. 2000). No
mountain plovers were found during searches conducted in Alberta and
Saskatchewan in 2001 (C. Wershler, Sweetgrass Consultants, pers. comm.
2002).
Mountain plover breeding behavior was observed in 1998 in Nuevo
Leon, Mexico, and one nest was found on a Mexican prairie dog colony in
1999 (Knopf and Rupert 1999a, Desmond and Ramirez 2002).
We believe that Montana, Wyoming, and Colorado represent the
historic and current core mountain plover breeding range, although
additional peripheral locations in Oklahoma and New Mexico may play an
important role in the species' conservation.
Historically, mountain plovers have been observed during the winter
in California, Arizona, Texas, Nevada, and on the California coastal
islands of San Clemente Island, Santa Rosa Island, and the Farallon
Islands (Strecker 1912; Swarth 1914; Alcorn 1946; Jurek 1973; Garrett
and Dunn 1981; Jorgensen and Ferguson 1984; B. Deuel, American Birds
Editor, in litt. 1992; D. Shroufe, in litt. 1999). In Mexico, wintering
mountain plovers have been sighted in
[[Page 53087]]
Baja California, as well as north-central and north-eastern Mexico, in
Sonora, Chihuahua, Coahuila, Durango, Nuevo Leon, and San Luis Potosi
(Russell and Lamm 1978; A. Garza de Leon, The Bird Galley, in litt.
1990; L. Stenzel, Point Reyes Bird Observatory, in litt. 1992; Gomez de
Silva et al.1996; Knopf and Rupert 1999a; Dieni et al. 2003, J. Taylor,
pers. comm. 2003).
All information we have reviewed indicates that California is the
primary wintering ground for mountain plovers, supporting up to 95
percent of the United States' population of mountain plovers (Morey, in
litt. 2003). However, recent isotope studies indicate that there may be
a disproportionate number of males in the wintering flocks. Seventy-
five percent of the feathers sampled from the Imperial Valley in the
winter of 2002 were from males, and sixty-two percent were from males
in the winter of 2003. This could indicate a slightly higher female
mortality, or perhaps differential migration patterns between male and
female plovers (e.g. females wintering farther south into Mexico). More
stable isotope work in the next two years may help answer this question
(Knopf, pers. comm. 2003).
Mountain plovers are most frequently reported and found in the
greatest numbers in two general locations in California--(1) The
western Central Valley from Solano and Yolo Counties to Kern County
(primarily the western San Joaquin Valley), and (2) the Imperial Valley
in Imperial County. Throughout these areas, sightings occur on
agricultural fields and noncultivated sites. Research conducted in the
San Joaquin Valley concluded that the noncultivated sites are the
preferred habitat there, while cultivated sites are the exclusive
habitat in the Imperial Valley (Knopf and Rupert 1995, Wunder and Knopf
2003).
From 1961 to 1968 anywhere from 25 to 10,000 mountain plovers were
counted in winter on Kern National Wildlife Refuge in the San Joaquin
Valley (J. Engler, Service, in litt. 1992). In January 1994,
researchers counted 3,346 mountain plovers during a simultaneous 1-day
survey of 25 sites throughout California (B. Barnes, National Audubon
Society, in litt. 1994). A similar coordinated survey at 31 sites in
the Central and Imperial valleys in January 1998 estimated 2,663
mountain plovers (Hunting et al. 2001). In December 1999, two skilled
observers were unable to find any mountain plovers in the entire San
Joaquin Valley after 2 days searching traditionally occupied sites
(Dinsmore, in litt. 2000b), which may have been due to degraded habitat
conditions following heavy rains (F. Knopf, pers. comm. 2000). On
February 2, 2002, 536 mountain plovers were counted in the entire San
Joaquin Valley, which may indicate some recovery of habitat conditions
since 1999 (S. Fitton, in litt. 2002). Within the San Joaquin Valley,
premigratory flocks of up to 1,100 birds have been seen in Tulare
County (Knopf and Rupert 1995). The Carrizo Plain (separated from the
San Joaquin Valley by the Tremblor Range) also is recognized as a
predictable wintering site, with wintering birds reliably reported from
the west side from 1971 to 1998 (S. Fitton, in litt. 1992,
www.birdsource.org 2000). Solano and Yolo Counties in the Central
Valley near Sacramento also provide wintering habitat for mountain
plovers, with about 200 being seen in these counties in recent years
(K. Hunting, California Department of Fish and Game, in litt. 1998; C.
Conard, Sacramento Audubon, in litt. 2003).
Wunder and Knopf (2003) suggested that many mountain plovers have
apparently shifted from the Central Valley as a result of habitat loss
to southern California and the Imperial Valley. Recent search efforts
and records for the Central Valley classify the mountain plover as rare
and local, exceedingly rare, or accidental, within individual counties
in the San Joaquin Valley (Edson and Hunting 1999; K. Hunting,
California Fish and Game, pers. comm. 2003).
In the Imperial Valley, coordinated surveys occurred in February,
November, and December 1999. The maximum effort of 26 observers in 15
parties over 2 days located 3,758 mountain plovers in December (Shuford
et al. 2000). From January 9-19, 2001, 4,037 mountain plovers were
counted by 2 observers in the Imperial Valley (Wunder and Knopf 2003),
and 3,421 were counted there from January 29 to February 6, 2002, by 4
observers (S. Myers, AMEC Earth and Environmental, pers. comm., 2002).
In the 2002 Christmas Bird Count (CBC) for that area only 12 were
counted; surveys were abandoned in January 2003 when the birds could
not be found following heavy rains (Knopf, pers. comm, 2003).
The only consistently collected information available to judge a
population trend are the CBC data. The CBC data from 1955-1999 from all
count circles in California reporting mountain plovers indicated a
decline in mountain plovers of about 1 percent annually (J. Sauer, U.S.
Geological Survey--Biological Resource Division (USGS-BRD), in litt.
2000; Wunder and Knopf 2003). This equates to a 35 percent decline in
the population from 1955 to 1999 (J. Sauer, pers. comm. 2003). The CBC
numbers fluctuate greatly from year to year based on observer
variability, survey intensity, and the spatial and temporal
distribution of mountain plovers (AMEC Earth and Environmental 2003).
Arizona, Texas, Nevada, and Mexico--Wintering mountain plovers also
are reported from other areas, but in much lower numbers than are
reported from California. From 1914 to the present, up to 340 mountain
plovers have been reported during the winter from Cochise, Maricopa,
Pima, Pinal, and Yuma Counties in Arizona (D. Shroufe, in litt. 1999).
In Texas, up to146 mountain plovers were reported from Guadalupe, San
Patricio, and Williamson Counties (J. Maresh, no affiliation, pers.
comm. 1999; G. Lasley, American Birds, pers. comm. 1992). Mountain
plovers also have been sighted throughout the year in Aransas, Concho,
Kleberg, Nueces, Schleicher, Tom Green, and Val Verde Counties in Texas
(P. Horner, in litt. 1997), and at Laguna Atascosa National Wildlife
Refuge on the Texas coast (L. Laack, Service, in litt. 1992). About 400
wintering mountain plovers were reported in west Texas in 2003 (T.
Fennell, unaffiliated, in litt. 2003). In Nevada, several mountain
plovers were collected in the Lahontan Valley in 1940, and a few have
been reported in the Fallon CBC circle in the 1990s (Alcorn 1946,
www.birdsource.org 2000). In January 1992, researchers counted 148
mountain plovers at the north end of Laguna Figueroa, Baja California,
Mexico (L. Stenzel, in litt. 1992). In 1994, mountain plovers were seen
on a Mexican prairie dog colony in San Luis Potosi, Mexico (Gomez de
Silva et al. 1996). In January 2000, 110 mountain plovers were found on
black-tailed prairie dog colonies in Chihuahua, Mexico (S. Gillihan, in
litt. 2003). Winter surveys for mountain plovers in Mexico completed
during the past several years have failed to find any populations that
approach the numbers found in California (R. Estelle, pers. comm.
1998).
In summary, with the heightened awareness to wintering mountain
plovers during the past decade (including black-footed ferret recovery
planning on prairie dog colonies in Mexico), and the mountain plover's
winter flocking behavior, we believe it is unlikely that significant
numbers of mountain plovers are not being detected. The widespread
distribution of the species makes it difficult to obtain comprehensive
population counts.
[[Page 53088]]
Previous Federal Action
On December 30, 1982, we designated the mountain plover as a
category 2 candidate species, meaning that more information was
necessary to determine whether the species status was declining,
stable, or improving (47 FR 58458). In 1990, we prepared a status
report on the mountain plover indicating that Federal listing may be
warranted (Leachman and Osmundson 1990). We elevated the mountain
plover to a category 1 candidate species in the November 15, 1994,
Animal Candidate Notice of Review (59 FR 58982). At that time, category
1 candidate species were defined as those species for which we had
sufficient information on biological vulnerability and threats to
support issuance of a proposed rule to list. In 1996, we redefined
candidate species and eliminated category 2 and 3 candidate
designations (61 FR 64481). Candidate species were defined using the
old category 1 definition. The mountain plover retained its candidate
species designation as reported in the September 19, 1997, Review of
Plant and Animal Taxa (62 FR 49398). On July 7, 1997, we received a
petition to list the mountain plover as threatened from the
Biodiversity Legal Foundation. The Service responded by notifying the
petitioner that petitions for candidate species are considered second
petitions, because candidate species are species for which we have
already decided that listing may be warranted. Therefore, no 90-day
finding was required for the Biodiversity Legal Foundation's petition.
We published a proposed rule to list the mountain plover as threatened
on February 16, 1999 (64 FR 7587), and requested that comments be
provided by April 19, 1999. We announced public hearings for the
proposal on April 19, 1999, and concurrently extended the comment
period to June 21, 1999 (64 FR 19108).
Higher priority listing actions precluded listing work on the
mountain plover during Fiscal Years 2000 and 2001. On October 16, 2001,
Earthjustice (representing the Biodiversity Legal Foundation,
Biodiversity Associates, and Center for Native Ecosystems) submitted a
60-day Notice of Intent to sue to the Secretary of the Department of
the Interior and the Service Regional Director for failure to meet
listing deadlines for the mountain plover, as required by section
4(b)(6)(A) of the Act. The Service responded to Earthjustice on
December 21, 2001, with a commitment to submit an amended listing
proposal for the mountain plover by September 30, 2002. On October 7,
2002, we agreed to prepare a document to reopen the public comment
period for this listing decision by November 30, 2002; hence, the
December 5, 2002, notice to reopen the comment period (67 FR 72396). On
February 21, 2003, we extended the comment period to March 21, 2003 (68
FR 8487).
Summary of Comments Received on the Proposed Rules
In both the February 16, 1999, proposed rule (64 FR 7587) and the
December 5, 2002, proposed rule (67 FR 72396), all interested parties
were requested to submit factual reports or information that might
contribute to the development of a final determination. Federal and
State agencies, county governments, scientific organizations, and other
interested parties were contacted and requested to comment. Several
newspaper articles appeared in Montana, Wyoming, and Colorado following
our distribution of background materials to print media. We also
solicited and received the expert opinions of three independent
specialists regarding pertinent scientific or commercial data and
issues relating to the biological and ecological information for the
mountain plover. We received a total of 194 written comments on the
1999 proposed rule.
We distributed a press release to announce the 2002 proposed rule.
We again solicited peer review of independent specialists regarding the
listing proposal and special rule. We received a total of 65 written,
e-mail, or telephone comments on the 2002 proposed rule.
In response to the 1999 proposed rule, public hearings were
requested in Nebraska by the Forest Service; in Montana by the Phillips
County Prairie Ecosystem Action Council, the Phillips County Board of
County Commissioners, and Erin Crowder; and in Wyoming by the Park
County Board of County Commissioners, Wheatland Irrigation District,
Wyoming Farm Bureau Federation, Laramie County Conservation District,
Platte County Resource District, Antelope Grange, Mountain Valley
Livestock, Inc., Ultra Resources, and John and Phyllis Thalken.
Public hearings were held at the following locations and dates:
[sbull] Billings, Montana, May 26, 1999.
[sbull] Malta, Montana, May 25, 1999.
[sbull] Greeley, Colorado, May 25, 1999.
[sbull] Lamar, Colorado, May 26, 1999.
[sbull] Casper, Wyoming, June 2, 1999.
We received written and verbal comments from State and Federal
elected officials, State and Federal agencies, nongovernmental
organizations, and private citizens. We received a total of 52 comments
at the 5 public hearings. Of the total 246 written and verbal comments
received on the 1999 proposed rule, 136 opposed, 41 supported, 53
expressed concern about the proposal, and 16 sought a list of the
references or requested public hearings.
Following release of the December 5, 2002, proposed rule, we
received requests for public meetings from Congressman Bob Filner
representing the 50th District of California, the Oklahoma Farm Bureau,
the Kansas Farm Bureau, and the Nebraska Farm Bureau. Following
discussions with each of these individuals, we held public meetings at
the following locations:
[sbull] El Centro, California, January 23, 2003.
[sbull] Elkhart, Kansas, February 5, 2003.
The Service distributed news releases announcing the meetings in El
Centro, California, and Elkhart, Kansas, on January 16, 2003, and
January 29, 2003, respectively. Notification of the Elkhart meeting
also appeared on the local access television station within the
Elkhart, Kansas, viewing area.
We received a total of 11 verbal comments from the 2 public
meetings held in 2003. Of the total of 75 verbal and written comments
received on the December 5, 2002, proposed rule, 25 comments opposed
the listing proposal, 15 supported the proposal, 24 expressed concern,
and 11 requested an extension of time or public hearing.
All written and verbal comments presented at the public hearings
and received during the public comment period, including peer review
comments, were considered in preparing this final determination. Most
of the comments opposing the action criticized the quality of the
science used to support the proposal, stated that we did not thoroughly
address each listing factor, noted the potential for the Federal
listing to restrict activities on both public and private lands, and
suggested that listing should be delayed to allow other alternatives to
work to conserve the species (e.g., conservation agreements). Some
comments also challenged the value of listing the species, and argued
that listing the mountain plover will conflict with other species'
conservation efforts and the implementation of other Federal programs.
Other respondents supported listing because of the decline in the
distribution and numbers of mountain plovers and the potential future
natural or man-caused actions to result in further decline of the
species, and also asked that critical habitat be designated. Each of
the five peer reviewers (three in
[[Page 53089]]
1999, two in 2002) indicated that the proposed rule contained
sufficient scientific information to support proposed listing. We have
consolidated similar comments, organized them by central themes, and
provide our responses below.
Listing Decision Statute Issues
Comment 1: The Service has violated statutory intent by not
complying with `the best information available' standard, has
inappropriately `piggybacked' a new proposal on the `stale' 1999
proposal, and has shown deferential treatment to environmental
organizations, evidenced by the settlement agreement with Earthjustice.
Response 1: This final determination presents a significant amount
of new information that has become available since the 1999 proposed
rule, including new information that caused us to discount Breeding
Bird Survey (BBS) trends as statistically insignificant, and to
reconsider what we earlier proposed as threats on agricultural lands on
the breeding grounds. The settlement agreement does not reflect
preferential treatment, but rather an appropriate means to resolve
litigation where the final determination was overdue.
Comment 2: E-mails, personal communications, and letters do not
meet the `best information available' standard as described in Service
policy (59 FR 34271).
Response 2: Our policy, as cited above, requires that we evaluate
all scientific and other information available, which may include both
published and unpublished materials, in the development of a listing
action. We review the information, regardless of origin, and determine
whether it is reliable, credible, and represents the best information
available regarding the species under review. We must document our
evaluation of any information we use in reaching our decision, whether
it supports or refutes that decision.
Biased Decision Issues
Comment 3: Several commenters stated that our analysis of the
mountain plover population trend data, grassland conversion statistics,
oil and gas development projections, prairie dog population data, and
other issues, are specific examples of the Service's use of `selective
science.' The commenter believe the Service has `selected science' to
defend a listing position in the proposed rules, while ignoring
information that defends the withdrawal of the listing proposal.
Response 3: During the two public comment periods in 2002 and 2003,
we received numerous comments from affected States and other interested
parties. We have based our decision on our review of all the pertinent
information we received. This determination includes new and additional
information, including research results, that was not available for the
proposed rule.
Comment 4: The multiple-clutch breeding system of the mountain
plover influences the annual fluctuation in the population, and
prepares the mountain plover for a changing environment.
Response 4: Multiple-clutching is believed to be a strategy that
allows the mountain plover to respond to abundant prey (Graul 1973)
which can, therefore, result in annual fluctuations in mountain plover
numbers at individual breeding locations. We agree that annual
fluctuations in mountain plovers may be in response to prey, but the
affect of multi-clutching on population trends is unknown.
Comment 5: The Service understated the effects of predation on
mountain plovers, did not consider the invasion by red fox (Vulpes
vulpes), and did not describe what is going to be done to reduce
predation effects on mountain plovers. Predation has a much greater
effect on the mountain plover population than losses on croplands.
Response 5: We have revised the section on predation to include red
fox as a potential predator, and assess the implications of predation
to mountain plover conservation. However, red fox are not typically
associated with habitats occupied by mountain plovers.
Comment 6: The Service has not identified or quantified actual
threats and, therefore, has not shown that mountain plovers have
declined or are at risk.
Response 6: The commenter is correct that we have not quantified
the threats to the mountain plover or the number of individuals lost as
a result of each threat. We have based our determination to withdraw on
the wide distribution of the mountain plover and the relative security
of the species from present or foreseeable threats across its current
range.
Habitat Characteristics Issues
Comment 7: Mountain plovers are not at risk when nesting on
croplands. Current agricultural practices are beneficial to the
mountain plover.
Response 7: In the 1999 proposed rule, we stated that agricultural
practices on cultivated lands may contribute to the decline of mountain
plovers. Research has confirmed that some nests are lost to some
cultivation practices (Dreitz and Knopf, in litt. 2003). As reported in
this final determination, preliminary research findings from Colorado
suggest that nesting success on cultivated lands does not differ
significantly from nesting success on grassland nesting sites (Dreitz
and Knopf, in litt. 2003). We agree that nesting success on some
croplands is similar to that found on grasslands, but the relative
influence of each landscape on mountain plover population recruitment
has not been determined.
Comment 8: Cultivated lands provide habitat where none existed
before.
Response 8: Cultivated lands have replaced grasslands within the
historic breeding and wintering range of the mountain plover. Hatching
success on cultivated lands and grasslands appears to be similar in the
southern portion of the breeding range.
Comment 9: Mountain plovers are an adaptable species, and have
effectively shifted from grasslands to cultivated lands in many
breeding and wintering areas. Cultivated lands, not grasslands, are now
the most important habitat for mountain plovers at both breeding and
wintering locales.
Response 9: See response to Comments 7, 8, and 21.
Comment 10: The role of insect availability has not been thoroughly
evaluated, particularly given that livestock dung is less abundant than
bison dung, and the prevalence of dung influences insect abundance.
Also, systemic insecticides are used on cattle, which reduces insect
availability.
Response 10: We agree that the role of insect availability has not
been thoroughly evaluated. However, no information has been provided to
show that insect abundance or diversity have been significantly
modified by the replacement of bison with domesticated livestock, or
that the use of systemic pesticides influences insect abundance or
composition.
Comment 11: Mountain plover habitat is provided by several factors
such as low moisture, drought, herbivory, fire, and grazing. In
Montana, unique soil types are the key element in defining suitable
mountain plover habitat. Prairie dog colonies are not the only suitable
habitat.
Response 11: We agree that numerous factors can provide suitable
mountain plover habitat. We agree that soils are important to providing
the vegetation and bare ground required by nesting mountain plovers.
For example, Beauvais and Smith (2003) stated that poor soil, low
precipitation, and wind scour help provide the proportion of bare
ground needed by nesting mountain plovers in the Jack Morrow
[[Page 53090]]
Hills area of southwest Wyoming. However, the literature also is
replete with examples documenting the association of mountain plovers
with prairie dogs (e.g., Dinsmore 2001, Knowles 1999, Kotliar et al.
1999).
Comment 12: Habitat fragmentation and isolation increase the
mountain plovers vulnerability to random natural and human-caused
events.
Response 12: No scientific information specifically discusses the
influence of fragmentation or isolation on the persistence of mountain
plovers at currently occupied breeding and wintering sites.
Comment 13: The anticipated growth at South Park will impact
mountain plovers and their habitat.
Response 13: Complete development of South Park into private homes
would probably adversely impact mountain plover. However, the
anticipated growth at South Park will be low-density residential
development, and full build-out is not anticipated in the foreseeable
future since the current human population in Park County is small
(16,000 people). It also is likely that conservation efforts ongoing in
South Park will preserve important mountain plover habitat.
Consequently, we believe potential threats to mountain plovers that
might result with development will be offset by conservation measures
implemented at the State and county levels.
Mountain Plover Distribution Issues
Comment 14: All suitable habitat on private and public lands
throughout the breeding range of the mountain plover has not been
thoroughly inventoried. Additional searching in the breeding range has
consistently found more mountain plovers.
Response 14: We have revised the population estimates for
individual States based on new information from commenters and
literature. We agree that surveys on all private lands in the breeding
range could reveal additional birds. For that reason, in addition to
the birds' flocking tendencies in winter, and 44 years of CBC data, we
base our total population estimate on counts from wintering habitat in
California, not on a summation of counts from breeding locales.
Mountain plovers occurring at undetected breeding locations would be
expected on the winter habitat from October through mid-March. This
estimate assumes that most of the birds winter in California.
Comment 15: All wintering areas in the United States or Mexico have
not been located. Further searching will yield more wintering sites and
more mountain plovers.
Response 15: All historic and current information we have reviewed
support California as the key wintering location for mountain plovers,
with many fewer numbers occurring elsewhere. Searches for mountain
plovers on wintering grounds in Mexico have been ongoing for the past
several years. We agree that additional searching is likely to find
other sites used by mountain plovers, but we believe that finding large
numbers of wintering mountain plovers will be highly unlikely, given
the level of effort dedicated in the United States and Mexico over the
past decade to locating mountain plovers. We have revised this section
of our determination to cite new information provided during the
comment period.
Mountain Plover Total Population and Trends Issues
Comment 16: The mountain plover is declining throughout its range,
and its current abundance is low compared to other bird species.
Response 16: The CBC data from wintering grounds in California
identify a slow decline in mountain plover abundance the last 44 years.
However, the numbers vary widely from year to year, and their accuracy
cannot be determined with any certainty.
Comment 17: The population estimate in the 1999 and 2002 proposed
rules is just ``a guess'' and is not reliable.
Response 17: The majority of wildlife population numbers are
estimates, because it is rarely possible to count all the individuals
of a species to develop a precise population number. We have relied on
practices accepted in conservation science, using the best information
available to us, to provide the public with a total population
estimate. The total population estimate of 8,000 to 10,000 individuals
was made by Dr. Fritz Knopf, a Senior Scientist with USGS-BRD in Fort
Collins, Colorado. Dr. Knopf has been studying mountain plovers since
1986, and has published widely on the mountain plover throughout its
range. We believe he is well qualified to make a population estimate.
Dr. Stephen Dinsmore, who recently completed his doctoral research on
mountain plovers in Montana, agrees with the population estimate. The
only other estimates available are those we have developed for
individual States in the breeding range based on other sources of
information.
The estimate is based on a 1-day coordinated survey on the winter
habitat in 1994, which was conducted by 95 observers covering 25 sites
in 9 counties. In addition, both planned and incidental searches to
locate and report mountain plovers in California have been ongoing for
decades.
Many respondents challenged the reliability of the population
estimate because of its reliance on a 1-day winter survey, and its
failure to include the numerous mountain plovers that they believe
occur on private lands throughout the nesting range. Counting animals
on their winter habitat is an accepted technique for estimating the
abundance of many species, with migratory waterfowl and big game being
two examples. The survey coordinated by the National Audubon Society in
California was a legitimate approach to monitor a wintering species,
and represented a new effort to count mountain plovers.
The commenters are correct in stating that the population estimate
alone cannot be used as a basis for listing. We have provided the
abundance and distribution information to give the public a better
sense of the status of the mountain plover.
Comment 18: How can the Pawnee National Grassland and Charles M.
Russell National Wildlife Refuge be important when so few mountain
plovers occupy these sites?
Response 18: We emphasized the significance of the Pawnee National
Grassland because of its historic importance to the mountain plover,
its Federal ownership and management, and its potential contribution to
mountain plover conservation. We identified the Charles M. Russell
National Wildlife Refuge because of its location in Phillips County,
Montana, an area with suitable and potentially suitable habitat and
currently one of the largest breeding mountain plover populations. We
believe each of these properties, with proper management, can make
significant contributions to mountain plover conservation on public
lands.
Comment 19: The Service did not acknowledge that Dr. Walter Graul's
1976 population estimate for the Pawnee National Grassland is now
considered inaccurate.
Response 19: We discussed this issue with Dr. Graul in preparing
this final determination. The commenter correctly notes that subsequent
to Dr. Graul's 1976 estimate of 20,000 mountain plovers on the Pawnee
National Grassland, he stated that it may have been off by an order of
magnitude. Dr. Graul provided the 1976 estimate to satisfy a request of
the American Ornithological Union to establish a relative magnitude of
abundance for the mountain plover. However, Dr. Graul believes that
mountain plovers were much more numerous during his
[[Page 53091]]
research than have been noted in recent years by himself or Dr. Fritz
Knopf. Consequently, while our use of historic numbers to show a
declining trend at the Pawnee National Grassland can be challenged, Dr.
Graul and Dr. Knopf both agree that a significant decline has been
evident since the late 1960s. We have revised the appropriate section
of the final determination.
Comment 20: The present and future change in winter habitat in
California is a significant range-wide threat to mountain plovers.
Response 20: As described in this final decision, we do not believe
the anticipated conversions of cultivated and noncultivated habitats in
California will have an immediate significant impact on wintering
mountain plovers throughout California. We discussed this issue with
Dr. Fritz Knopf for preparation of this final determination (F. Knopf,
pers. comm. 2003). Dr. Knopf agreed that winter habitat does not appear
to be limited, but acknowledged that habitat quality may not be similar
among all cultivated and noncultivated lands. Mountain plovers are
opportunistic foragers while they occupy winter habitat, and have the
ability to seek suitable habitats available over a wide area. Knopf and
Rupert (1995) determined that mountain plovers prefer noncultivated
sites to cultivated lands, and others have observed that mountain
plovers appear to select unique characteristics (E. Marquis-Brong, BLM,
in litt. 1999). However, given that cultivated habitat is pervasive
throughout the Imperial and Central Valleys, we do not believe the
current rate of conversion represents an imminent threat to mountain
plovers.
Comment 21: Mountain plover numbers are very dynamic, and their
current abundance merely reflects a normal fluctuation.
Response 21: We agree that mountain plover abundance at local
breeding areas can fluctuate annually based on local environmental
conditions.
Comment 22: Population fluctuations due to climatic events should
be considered temporary and not a justification for listing.
Response 22: The Service must consider all factors, natural or
human-caused, that may contribute to a species' survival and recovery.
We agree that climatic events may affect localized populations, either
positively or negatively, on a temporary basis. Presently, it is
believed that climatic events on the Pawnee National Grassland have
negatively influenced mountain plover abundance there.
Comment 23: The BBS data are not reliable. The 2002 proposed rule
stated that new BBS information was available, but new BBS information
could not be found.
Response 23: The 1999 proposed rule cited literature published by
Dr. Fritz Knopf, which used published BBS trend analyses reporting the
mountain plover declining throughout its range, and declining more
rapidly than other grassland endemic birds. His conclusions were based
on the BBS data for the periods from 1966 to 1993. The 1999 proposed
rule also cited an analysis by Dr. John Sauer with the USGS-BRD,
showing that for the period 1966 to1996, the BBS trend analysis yielded
a statistically significant estimated annual rate of decline of 2.7
percent. Because of the numerous comments we received on the 1999
proposed rule regarding the BBS data, we requested a review of the data
by the USGS-BRD, which is the Federal agency responsible for
administering the BBS program.
According to Sauer (in litt. 1999), the survey-wide trend analysis
lacked statistical confidence due to the wide variability in mountain
plovers reported from individual routes in each of the years from 1967
to 1998. We concluded that, although the BBS is the only long-term
trend information available in the breeding range, it is not a
statistically reliable indicator of mountain plover population trends.
Comment 24: A commenter criticized the 30-year-old National
Wildlife Refuge records because of a lack of information, the
variability in observer experience, and inconsistency in survey routes
followed.
Response 24: In 1992, we received a report from the Kern National
Wildlife Refuge that consolidated mountain plover observations and
discussed their historic and current status on the Kern and Pixley
National Wildlife Refuges in California (J. Engler, Service, in litt.
1992). The report included observation records from 1961 to 1991, and
lacked data for many years during that period. The records of mountain
plover sightings from the refuges were collected during inventories for
waterfowl, which included observations of migrating shorebirds and
other species. It is common for annual waterfowl surveys to be
conducted by different people, given staff turnover and personnel
availability. However, refuge biologists are thoroughly trained in bird
identification, and, more importantly, because the mountain plover was
known as a regular resident of these refuges, we are confident that the
biologists completing the survey were able to correctly identify
mountain plovers when encountered. We agree that the refuge data
provide an approximate estimate rather than a precise number of
mountain plovers wintering on the refuge.
Comment 25: The CBC data are unreliable because count circles are
not always the same over time, errors have been published by American
Birds, the number of individuals reported could be wrong, and the wrong
species can be reported.
Response 25: We agree that CBC numbers fluctuate greatly from year
to year based on observer variability, survey, intensity, and the
spatial and temporal distribution of mountain plovers. We contacted Mr.
Geoff LeBaron of the National Audubon Society, who is in charge of the
CBC surveys and is responsible for analyzing the data; he is familiar
with the suggested limitations (G. LeBaron, National Audubon Society,
pers. comm. 1999). Mr. LeBaron agreed that some count circle centers
may change over time, due to encroachment of development within the
count circle and, therefore, may not be completely ``static'' over the
entire period of record. However, he did not believe this seriously
compromises the quality of the data for the geographic area over the
long term. He also agreed that the other limitations cited by the
commenter can occur when field data are being evaluated for species
that occupy similar habitats, or are similar taxonomically. However,
because the mountain plover is unique in these respects and, therefore,
unlikely to be confused with any other species by experienced
observers, he does not believe any of these limitations apply to the
mountain plover. The Anadarko Petroleum Corporation retained Dr. Mark
Boyce to analyze the CBC data (M. Boyce, University of Alberta, in
litt. 2003). Dr. Boyce's analysis did not refute the conclusions of Dr.
John Sauer with USGS-BRD (in litt. 2000). We have revised the section
in this final determination to report additional information regarding
the CBC.
Comment 26: Population trends of the mountain plover at the Pawnee
National Grassland are indicative of the total population trend.
Response 26: There is no scientific evidence to support the claim
that the precipitous decline documented at the Pawnee National
Grassland has influenced the total mountain plover population.
Comment 27: The mountain plover's short lifespan makes the species
vulnerable to decline.
Response 27: There is no scientific evidence to support the
commenter's claim that the mountain plover's risk of
[[Page 53092]]
extinction is exacerbated by a short lifespan.
Grassland Conversion Issues
Comment 28: Grassland conversion has destroyed mountain plover
habitat and resulted in a decline in mountain plovers.
Response 28: We are unable to precisely quantify the amount of
mountain plover habitat that has been lost due to agricultural
conversions and, therefore, are unable to precisely quantify the impact
to mountain plovers. We do not believe the present or future conversion
of grasslands is an imminent threat to all mountain plover breeding
locations, throughout the species' range.
Comment 29: The Service overstated the loss of grasslands as an
impact on breeding mountain plovers, because the rangeland loss
reported in the 2002 proposed rule is minuscule relative to total
rangeland available. This means that the impact to mountain plover
habitat is even smaller and, therefore, of no consequence.
Response 29: We agree that most grassland conversion occurred prior
to 1982, and that the proportion of rangeland lost to total rangeland
from 1992 to 1997 is small. We have revised the section of the final
determination addressing grassland conversion.
Comment 30: The Service inappropriately analyzed the National
Resource Inventory database in its description of rangeland conversion
loss, and the implications to mountain plover habitat.
Response 30: Because we are unable to precisely differentiate
mountain plover habitat from among the NRI cover types, the NRI data
are of little value in clearly and concisely assessing the degree of
threat to mountain plovers or their habitat. We have revised the
section of the final determination.
Comment 31: Some commenter stated that the presence of thousands of
acres of Conservation Reserve Program (CRP) lands represents a threat
to mountain plover habitat. Other commenter complained that the Service
has not given credit to the thousands of acres of grassland created by
the CRP.
Response 31: The CRP administered by the Department of Agriculture
allows producers to retire lands for 10-year periods to remove highly
erodible soils from production, thereby benefitting wildlife and other
resources. As of 1992, 2,002,000 ha (4,946,000 ac) of land were
enrolled in the program in Colorado, Montana, and Wyoming, and most of
these lands were planted to grass (Berlinger and Knapp 1991, Lesica
1995). The wildlife that benefit most from these practices (such as
ring-necked pheasant, northern bobwhite, and western meadowlarks) are
those associated with tall vegetation (Schenck and Williamson 1991),
although within each State, the Department of Agriculture has the
ability to plant a variety of grass species, including short grasses
that benefit mountain plover.
Comment 32: Wintering habitat is becoming a limiting factor. The
historic conversion of grassland in California impacted mountain
plovers, and future modifications of crop types, agricultural
practices, or urbanization will have additional impact.
Response 32: Mountain plovers demonstrate some flexibility on
winter habitat. Wunder and Knopf (2003) reported that agricultural
practices on croplands in the Imperial Valley are critical to wintering
mountain plovers, although Knopf and Rupert (1995) concluded that
grasslands were preferred by wintering mountain plovers to agricultural
fields in the Central Valley. While not all of the croplands are
suitable foraging habitat, and modification of practices on croplands
used for foraging could be detrimental to some mountain plovers, we do
not believe the rate of conversion occurring now is having a
significant influence on the total abundance of mountain plovers
throughout California.
Livestock Grazing, Range Management, and Farming Issues
Comment 33: Range management is a factor in the historic decline of
mountain plovers, and represents a current threat to existing mountain
plover populations. Grazing practices now are very similar to those
that were adopted decades ago.
Response 33: The prevailing grazing management standards adopted by
Federal agencies and grazing associations tend to maximize forage
production and diminish excessive disturbance to grass and soil. Such
practices can be detrimental to mountain plovers, although we have no
information to indicate this is happening on a broad scale across the
species' range.
Comment 34: The Service incorrectly stated that the Forest Service
has no schedule for revising grazing management prescriptions on the
Pawnee National Grassland.
Response 34: This final determination has been corrected to report
our recent coordination with the Forest Service regarding their planned
revisions to range allotment management plans on the Pawnee National
Grassland, which are designed in part to enhance mountain plover
breeding habitat.
Comment 35: Since farming practices have not changed in 50 years
how can there be any impact to mountain plovers?
Response 35: We recognize there are numerous small farming and
ranching operations that have retained historic practices that may
benefit mountain plovers. As a result of a variety of factors,
including more advanced technology and more effective agricultural
chemicals, the average farm size has increased. As the farms have
gotten larger, it is no longer feasible to till and plant a field
within a short period of time. Consequently the lands are tilled in
early spring when suitable habitat for mountain plover nesting is
present. Therefore, some nests are at risk from spring tilling if
measures are not taken to avoid nests. This final determination
describes the implications of current farming practices to mountain
plover conservation.
Issues Related to Prairie Dogs
Comment 36: We received numerous comments on the Service's
discussion of mountain plovers and prairie dogs, the abundance and
distribution of prairie dogs, and the role of prairie dogs in the
historic and current status of the mountain plover.
Response 36: This final determination cites published literature,
expert opinion, and other sources of available information to describe
the association of mountain plovers and prairie dogs. Of the many
comments received addressing prairie dogs, only one provided detailed
information to challenge our discussion regarding the distribution of
mountain plovers on prairie dog colonies in Montana. Recently, research
completed in southern Phillips County, Montana, affirmed a strong
association of mountain plovers with prairie dogs (Dinsmore 2001).
Therefore, based on our review of the information available, we
continue to believe breeding mountain plovers are strongly associated
with prairie dogs in Montana. We have revised the section on prairie
dogs to report new information.
Comment 37: The Service grossly underestimated the abundance of
prairie dogs and, therefore, grossly underestimated the abundance of
mountain plovers.
Response 37: The Wyoming Department of Agriculture is correct that
the current estimate of black-tailed prairie dogs in Wyoming is greater
than earlier Service estimates. However, it does not follow that the
mountain plover population is proportionately underestimated. As stated
above, we base our total mountain plover
[[Page 53093]]
population estimate on winter counts, not availability of breeding
habitat. We have revised the final determination to acknowledge the new
estimates for prairie dogs, and discuss the implications of prairie dog
abundance to mountain plover viability.
Comment 38: Prairie dog poisoning has increased.
Response 38: The Service has new information to suggest that
poisoning of black-tailed prairie dogs may have increased in some
States in the mountain plover's range (Service 2002.). We have revised
this section of the final determination to conclude that while prairie
dog poisoning may have increased locally, it does not represent an
imminent threat to mountain plovers throughout their breeding range.
Comment 39: Prairie dog shooting is a threat to mountain plovers.
Response 39: We agree that shooting black-tailed prairie dogs has
been shown to reduce prairie dog abundance at some locations. However,
it has not been shown to be a significant threat to maintenance of
black-tailed prairie dog colonies (Service 2002.). While it has the
potential to degrade or prevent recovery of habitat and impact mountain
plover breeding success, we believe those instances are localized and
infrequent. We have no information to indicate that the incidental
shooting of mountain plovers is significant.
Mineral Development Issues
Comment 40: Oil and gas development, including coalbed methane, is
a potential significant threat to mountain plovers.
Response 40: This final determination provides information
describing the potential effects to mountain plovers from oil and gas
development. The degree of effect depends on the density of mountain
plovers and level of oil and gas development within a project area.
Comment 41: The presence of mountain plovers at the Antelope Coal
Mine in Wyoming is evidence that mining does not impact mountain
plovers.
Response 41: We have revised the final determination to report new
information from the Antelope Coal Mine, including its potential
effects on mountain plovers.
Pesticide Issues
Comment 42: Inclusion of grasshopper control as a potential threat
is not valid because the rule admits that Federal grasshopper control
programs have been abandoned.
Response 42: The Animal and Plant Health Inspection Service (APHIS)
has recently authorized rangeland grasshopper control, and control of
grasshoppers can occur when they reach economic thresholds. We have
revised the final rule to report new information regarding pesticide
exposure from grasshopper control and from California wintering
habitat.
Regulatory Mechanisms
Comment 43: Existing regulatory mechanisms are inadequate to
protect the mountain plover.
Response 43: We have no evidence that the existing regulatory
mechanisms have contributed to the decline of the mountain plovers
throughout a significant portion of their range. The Forest Service and
the BLM routinely include the mountain plover in their planning
documents to ensure that activities they authorize do not contribute to
the further decline of the species. The NRCS has prepared a fact sheet
for the mountain plover to encourage farmland practices beneficial to
the mountain plover. The Service is developing a dialogue with all
Federal agencies to ensure that measures are included in land
management plans to protect and promote the conservation of the
mountain plover. Federal listing would not add significant conservation
benefit above those efforts presently adopted by Federal agencies.
Peer Review
In compliance with the July 1, 1994, Service Peer Review Policy (59
FR 34270), peer reviews were provided by five specialists. The peer
reviewers in 1999 were Dr. Marshall Howe with USGS-Patuxent Wildlife
Research Center, Dr. C.R. Preston with the Draper Museum of Natural
History in Cody, Wyoming, and Dr. James Dinsmore with Iowa State
University in Ames, Iowa. Each of these peer reviewers concluded that
there was sufficient information to list the mountain plover as
threatened. The reasons cited by the peer reviewers included small
population and declining trend of the species, prairie dog distribution
and decline, habitat loss to grassland conversion, the influence of
cropland nesting efforts on mountain plover conservation, and pesticide
exposure.
Two peer reviewers provided comments to the 2002 listing proposal.
One peer review was provided by Dr. Peter Paton with the University of
Rhode Island in Kingston, and the second peer review was provided by
Mr. Steve Forrest with Hyalite Consulting in Bozeman, Montana. Mr.
Forrest was selected by Earthjustice following the settlement agreement
reached between the Service and Earthjustice to expedite a listing
decision for the mountain plover. Both of these peer reviewers also
supported the proposal to list the mountain plover. The issues
identified by each of them were similar to those received from the peer
reviewers in 1999, but also included attention to other specific issues
such as declines in Weld County, Colorado, Montana, and Thunder Basin
National Grassland in Wyoming, as well as habitat fragmentation,
prairie dog shooting, and the proposed special rule.
Since the 1999 listing proposal and following the 2002 re-opening
of the comment period, we have acquired additional information
regarding the concerns identified by each of the peer reviewers, as
disclosed in this final determination.
Summary of Factors Affecting the Species
Section 4 of the Act (16 U.S.C. 1531 et seq.) and the regulations
(50 CFR part 424) that implement the listing provisions of the Act set
forth the procedures for adding species to the Federal list of
endangered and threatened species. A species may be determined to be
endangered or threatened due to one or more of the five factors
described in section 4(a)(1) of the Act. These factors and their
application to the mountain plover rangewide are discussed below.
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of its Habitat or Range
Historical and Current Conversion of Grassland in Breeding Range
As described in the 1999 and 2002 proposed rules, the historic
conversion of grassland to cropland likely contributed to the decline
of mountain plovers and their habitat (e.g., Graul and Webster 1976,
FaunaWest 1991, Knopf and Rupert 1999b). To assess more recent
grassland conversion, we reviewed information available from the
National Resources Inventory (NRI) of the U.S. Department of
Agriculture Natural Resources Conservation Service (NRCS) between 1982
and 1997. We selected the ``rangeland'' cover type because ``native
grassland'' is not a type category within the data base specifically,
but is represented under the rangeland category. Comprehensive NRI data
is only available from 1982 through 1997 (NRCS 1998; K. Musser, NRCS,
in litt. 2000; K. Musser, pers. comm 2002). We used only areas occupied
by mountain plovers in their breeding range to compare the rangeland
conversion statistics (Knowles and Knowles 1998, Shackford and Leslie
1995).
[[Page 53094]]
From 1982 to 1997, rangeland decreased in Colorado by 217,200 ha
(536,700 ac), in Kansas by 14,852 ha (36,700 ac), in Nebraska by 14,326
ha (35,400 ac), in Oklahoma by 16,512 ha (40,800 ac), in Montana by
59,894 ha (148,000 ac), and in Wyoming by 18,090 ha (44,700 ac). More
acres were converted prior to 1992 in all States except Nebraska and
Montana, where acres converted after 1992 were about the same or more
than doubled, respectively. The total lands converted are a small
fraction of the total rangeland. While the best information available
does not allow us to quantify the acres of occupied mountain plover
habitat converted, using the rate of rangeland conversion, we believe
native grassland conversion is small and does not pose a substantial
threat to mountain plovers.
The Montana Fish, Wildlife and Parks expressed concern over
conversion of native habitat in Montana (P. Graham, Montana Fish,
Wildlife and Parks, in litt. 1999). For example, Knowles and Knowles
(2001) reported that a total of 13 percent of the land area in their
central Montana study area has been converted from native grass from
1991 to 1999, and that mountain plovers have abandoned all but one of
the sites that were converted. Mountain plovers in the central Montana
study area declined from more than 100 in 1992 to about 70 individuals
in 2000, as a result of grassland conversion (Knowles and Knowles 2001;
C. Knowles, pers. comm. 2003).
Mountain plovers nest successfully on croplands in Colorado and
perhaps contiguous States (V. Dreitz and F. Knopf, in litt. 2003;
Shackford et al. 1999). While the findings are preliminary and
represent a small percentage of total croplands in eastern Colorado,
they suggest that existing croplands and grasslands in the southern
portion of the breeding range may be of equivalent value to nesting
mountain plovers (V. Dreitz and F. Knopf, in litt. 2002). In Montana
and northern Wyoming, nesting on cultivated land has not been observed
(Knowles and Knowles 2001; Shackford et al. 1999). However, since the
amount of rangeland converted is small (NRCS 1998), we conclude that
the impact to mountain plovers in Montana and northern Wyoming is
comparably small, regardless of how cultivated land is used by mountain
plovers in those states.
In some areas in the mountain plover breeding range, grasslands are
being converted to housing subdivisions. Of some concern is development
of nesting habitat in South Park, Park County, Colorado, where the
mountain plover population is now estimated to be about 2,300
individuals, which is the largest known remaining concentration of
mountain plovers in the breeding range (Wunder et al. in prep.). The
known breeding sites in South Park are vulnerable to ongoing and
proposed future residential development. Full build-out of those sites
currently subdivided would be detrimental to mountain plovers (Sherman
et al. 1996, Granau and Wunder 2001). However, it is unknown how
extensive future development will actually be or how fast it will
proceed, such that while it is a potential threat we have no reason to
believe that it means the species is likely to be in danger of
extinction in the foreseeable future. It also is likely that private
conservation efforts ongoing in South Park will preserve important
mountain plover habitat.
Cultivated Areas in Breeding Range as Potential Population Sinks
In the 1999 proposed rule, we stated that we believed cultivated
lands in the southern portion of the breeding range created population
sinks for the mountain plover, contributing to species decline. In an
effort to better define the implications to mountain plover survival,
research was initiated on cultivated fields and rangelands in five
counties in eastern Colorado in 2001 (T. McCoy, in litt. 2001).
Preliminary data analysis indicates that nest success is comparable
between cropland and rangeland (V. Dreitz and F. Knopf, in litt. 2003).
Nest failure was attributed principally to tillage and predation on
cropland, and to predation on rangeland (V. Dreitz and F. Knopf, in
litt. 2002). However, while hatching success on croplands and
grasslands is similar in the southern portion of the breeding range,
comparable data on juvenile survivorship are not available so mountain
plover reproductive success on cropland relative to grasslands is not
fully known (V. Dreitz and F. Knopf, in litt. 2002; Knopf, in litt.
2003).
Historical Conversion of Grassland in Wintering Range
Historically, mountain plover habitat in the Central Valley was
lost following the decline of grazing elk, pronghorn, burrowing
kangaroo rats, ground squirrels, and other mammals. The combined
activities of these herbivores maintained suitable habitat conditions
for mountain plovers, closely mimicking habitat characteristics found
on breeding habitats (Knopf and Rupert 1995). Elk are now extirpated
from the Central Valley, and pronghorns, once extirpated, have recently
been reintroduced into the Carrizo Plains (BLM et al. 1995). The
federally-listed giant kangaroo rat (Dipodomys ingens) and Tipton
kangaroo rat (Dipodomys nitratoides nitratoides) have declined to about
2 percent and 1 percent of their former range, respectively, due
primarily to conversion of grassland habitat to agriculture and
urbanization, and secondarily due to other incidental human activities
and control of California ground squirrels (W. White, Service, in litt.
2001a; 52 FR 283; S. Jones, Service, pers. comm. 2003). The occupied
range of each of these species in the San Joaquin Valley overlaps the
described wintering range of the mountain plover. Currently, it is
estimated that giant kangaroo rats may occupy about 11,145 ha (27,540
ac) and the Tipton kangaroo rat may occupy about 25,000 ha (63,000 ac)
(Service 1998). While we cannot measure the degree of impact to
mountain plovers resulting from the loss of these mammals, we believe
any further loss would be detrimental to the species by further
reducing natural habitats.
Native grasslands in the San Joaquin Valley have been nearly
eliminated. Of nearly 1,800,000 ha (4,400,000 ac) of native grasslands
present prior to extensive settlement, no more than 600 ha (1,500 ac)
remained in 1972 (Moore et al. 1990). This loss of grasslands has been
paralleled by a loss of other natural habitats, with the total of all
uncultivated lands in the San Joaquin Valley now occupying less than
61,000 ha (150,000 ac) (Service 1998).
Mountain plovers wintering in the San Joaquin Valley prefer native
Valley sink scrub and nonnative grasslands over any of the more
commonly cultivated land types (Anderson et al. 1991; Knopf and Rupert
1995) when the grasslands are grazed or burned (Knopf and Rupert 1995).
These preferred habitats occupy less than 26,000 ha (66,000 ac) of the
San Joaquin Valley (Anderson et al. 1991). Mountain plovers in the San
Joaquin Valley depend on these core areas of uncultivated lands in
October and November (Engler, in litt. 1992; Knopf and Rupert 1995),
and further loss of these areas would be detrimental to the species
(Knopf and Rupert 1995).
Mountain plovers use cultivated croplands in the Imperial Valley of
California, where in recent years (except the winter of 2002-03 when
excessive rain prevented it) greater than 50 percent of all individuals
of the species wintered (Wunder and Knopf 2003). Until agricultural
development began in the 1940s, this historically desert region was not
known to support the species. Here, 37 percent of the mountain
[[Page 53095]]
plovers forage and roost on grazed or sprouting alfalfa fields; 34
percent roost on short-term fallowed fields; and 13 percent forage on
burned bermuda grass fields, while ungrazed alfalfa, unburned bermuda
grass, melon and vegetable fields are rarely or never used (Wunder and
Knopf 2003).
Other habitats within the historic wintering range of the mountain
plover have been modified by modern livestock grazing practices that
maintain grass height that is higher than what mountain plovers can
use. This is the situation in the Carrizo Plain, which is recognized as
a predictable wintering area and historically may have provided up to
50 percent of suitable plover wintering habitat. No more than 10
percent of the Carrizo Plain's 103,000 ha (254,000 ac) was suitable for
mountain plovers in the early 1990s (S. Fitton, in litt. 1992; BLM et
al. 1995), but that figure has increased in recent years due to lower
precipitation (S. Fitton, pers. comm. 2003). Habitat availability there
appears to be linked to a combination of livestock grazing management
and precipitation.
We were unable to precisely quantify the acres of mountain plover
wintering habitat converted to other uses annually because a data base
quantifying mountain plover habitat does not exist. However,
information from the California Department of Conservation confirms the
routine conversion of existing croplands to vineyards, orchards, and
other uses. For example, from 1990 to 2000, the acreage of vineyards in
California nearly doubled to a total of 230,000 ha (570,000 ac) (M.
Penberth, California Department of Conservation, in litt. 2003). In
nine counties in the Central Valley where mountain plovers are now
reported as ``rare and local,'' the acres in vineyards increased by
about 25 percent (31,000 ha (76,000 ac)) from 1990 to 2000 (Edson and
Hunting 1999; M. Penberth, California Department of Conservation, in
litt. 2003). Conversion to vineyards represents a loss of potential
habitat, although the extent of use by plovers prior to conversion is
unknown.
Urban development destroyed most noncultivated, historic coastal
mountain plover winter habitat (Wunder and Knopf 2003), and anticipated
urbanization and water transfers from rural to urban areas may impact
the remaining natural habitats, as well as to existing cropland
habitats in both the Central and Imperial Valleys. In California, the
U.S. Census Bureau (2003) projected a 52 percent (17 million)
population increase from 2000 to 2025. Based on past trends,
considerable population growth is expected to occur in the Central
Valley (American Farmland Trust 2003, Hunting et al. 2001). The
Imperial County population is expected to nearly double by 2020
(American Farmland Trust 2003). In the Imperial Valley, the North
American Free Trade Agreement is expected to generate increased trade
growth, and highway projects are now being planned to improve
transportation efficiency (California Department of Transportation
2001). As a result of the anticipated population growth, the American
Farmland Trust (2003) designated the Imperial and Central Valleys 2 of
the top 20 threatened farming regions in the Nation. However, between
1982 and 1992, only 8,000 ha (19,000 ac) of land in Imperial County
were converted to urban uses. The present impacts to farm land in
Imperial County have had no measurable impact on wintering mountain
plovers. For example, the Service completed a draft biological opinion
for a proposed transfer of water from the Imperial Valley to southern
California coastal communities (P. Sorensen, Service, in litt. 2003).
It is presently estimated that if the water transfer occurs, 12,000 to
32,600 ha (30,000 to 80,500 ac) of bermuda grass sod farms and alfalfa
could be fallowed each year (C. Roberts, Service, pers. comm. 2002; P.
Sorensen, in litt. 2002), which we calculate would be from 15 to 39
percent of the available foraging habitat described by Wunder and Knopf
(2003). However, because of the mild winter climate in the Imperial
Valley, crops are not fallowed for long periods of time. Land that is
fallow 1 month may be tilled the next, presenting a shifting mosaic of
foraging habitat for plovers. Because it is unclear whether the water
transfer will occur and whether it will reduce foraging habitat for
mountain plovers in the Imperial Valley, we cannot conclude that loss
of cropland or modification of current practices threatens the species
in the foreseeable future.
In summary, although most natural habitat used by mountain plovers
in California has been destroyed, some crops that have replaced it
provide foraging and roosting habitat (Knopf and Rupert 1995, Wunder
and Knopf 2003). Given a high over-wintering survival rate in the San
Joaquin Valley and Carrizo Plain and the ability of the plovers to use
croplands successfully, Knopf and Rupert (1995) concluded that a loss
of a major proportion of native habitats in the wintering range has not
limited plover populations.
Mountain plovers have been reported in winter in other States in
the United States and Mexico, but in comparison to California their
numbers are few, and the threat of habitat destruction, modification,
or curtailment is unknown with one exception. In the 1990s, the Ejido
San Pedro CBC was initiated on a black-tailed prairie dog complex in
northwestern Chihuahua, Mexico (birdsource.org 1992-2002). Mountain
plovers have been reported in low numbers in most years, with no birds
reported in some years (birdsource.org 1993-2002). Vegetation has been
modified by livestock grazing to include woody shrubs, and prairie dog
densities are low, which allows for increased vegetation height.
In conclusion, after reviewing the current and anticipated impacts
to wintering habitat, we find that they do not pose significant threats
to the mountain plover.
Effects of Range Management on Mountain Plover Habitat
Domestic livestock grazing is pervasive throughout the breeding
range of the mountain plover. Currently accepted domestic livestock
grazing management emphasizes a uniform grass cover to minimize
grassland and soil disturbance, whereas the landscape created
historically by native herbivores was a mosaic of grasses, forbs, and
bare ground that changed frequently in time and location (Knopf 1996a,
Knopf and Rupert 1999b). The shift to livestock grazing strategies that
favor uniform cover is believed to be partly responsible for the
decline of mountain plovers in the peripheral breeding areas of
Oklahoma and Canada (Flowers 1985, Wershler 1989), but has only been
assessed in limited, localized instances elsewhere within the major
portion of the breeding range. Mountain plovers are no longer reported
from the Lewis Ranch in central Montana since elimination of grazing
there in 1993 (Knowles and Knowles 2001). The decline of mountain
plovers on the Pawnee National Grassland in Colorado is due to multiple
years of wet spring weather, persistent grazing systems, the apparent
difficulty of adjusting domestic livestock stocking rates to
accommodate years of increased forage, the lack of infrastructure to
modify grazing systems, and the sparse application of grassland burning
and mineral block placement to restore nesting habitat (Forest Service
1994; S. Currey, Forest Service, in litt. 2002; F. Knopf, in litt.
2002; R. George, in litt. 2002; E. Humphrey, Forest Service, in litt.
2003). These examples are localized and do not appear to exemplify
practices in a substantial portion of the breeding range. If the
impacts were significant, we would anticipate being able to detect a
declining trend in
[[Page 53096]]
abundance on the BBS, which shows a statistically significant decline
from 1966 to 2002 only in the extreme southern portion of the breeding
range where plover abundance is low and the number of routes detecting
the species are few (BBS, http://www.mbr-pwrc.usgs.gov/bbs/bbs.html).
Several range management practices conducted throughout the range
of the mountain plover enhance the development of taller vegetation,
thereby eliminating nesting opportunities (Graul and Webster 1976,
Knowles and Knowles 1993). Examples of these practices include
``pitting'' to increase moisture retention in the soil, introduction of
exotic grass species such as crested wheatgrass, watershed improvement
projects to retain water, and, in Montana, fire suppression (Graul
1980, FaunaWest 1991, Knowles and Knowles 1993).
Localized range management activities on private and public lands
also destroy mountain plover habitat. In 2001, for example, two known
mountain plover breeding sites were destroyed in Valley County,
Montana, by the construction of stock tanks in an area designated by
the BLM as an Area of Critical Environmental Concern for mountain
plover (C. Knowles, in litt. 2001).
Although range management activities may adversely affect some
habitat for the mountain plover in specific instances, the complete
absence of grazing causes mountain plover habitat to deteriorate.
Therefore, we see grazing as necessary for the species, and not a
threat to the species throughout its range.
Effects of the Decline of Burrowing Mammals on Mountain Plover Habitat
The historic decline in abundance and distribution of prairie dogs
likely contributed to the historic decline of the mountain plover
(Knowles et al. 1982; S. Fitton, in litt. 1992; Knopf 1994). The
mountain plover nests on active prairie dog colonies, principally those
of the black-tailed prairie dog (Cynomys ludovicianus), throughout its
breeding range, as prairie dogs maintain their preferred nesting
habitat of low vegetation structure and a high percent of bare ground.
Preliminary findings from Colorado suggest that mountain plover nesting
success is higher on black-tailed prairie dog colonies than sites
without prairie dogs (V. Dreitz and F. Knopf, in litt. 2002). Prairie
dogs were widespread and numerous throughout the mountain plover's
historic breeding range (Service 2002). Mountain plovers presently
occupy prairie dog colonies in Colorado, Montana, Wyoming, Oklahoma,
and New Mexico (Shackford 1991; Godbey 1992; Nelson 1993; Hawks Aloft
2001b; M. Edwards, in litt. 1994; T. Thompson, in litt. 2003; Dinsmore
2001). Montana, Wyoming, and Colorado likely comprised most of the core
mountain plover breeding areas historically, and currently there are
more mountain plovers associated with prairie dogs in those States. The
suitability of prairie dog colonies as mountain plover habitat appears
to be influenced by the individual colony size and prairie dog density
(Knowles et al. 1982, Olson-Edge and Edge 1987, Dinsmore 2001).
Therefore, total prairie dog acres is not a measure of total suitable
mountain plover habitat available.
Black-tailed prairie dogs have been reported to currently occupy
about 256,000 ha (631,000 ac) in Colorado (Pusateri, CDOW, in litt.
2002), 36,000 ha (90,000 ac) in Montana, and an estimated 50,000 ha
(125,000 ac) in Wyoming (Luce 2003). In Phillips County, Montana, 99
percent of the mountain plover nests found on survey transects were
located on active prairie dog colonies (Dinsmore 2001). The largest
population of mountain plovers in Montana (about 700 individuals)
occurs on black-tailed prairie dog colonies in Phillips County, and
mountain plover and prairie dog abundance are closely related there
(Dinsmore 2001). Mountain plovers seem closely tied to active prairie
dog colonies in Wyoming in the Powder River Basin, including Thunder
Basin, particularly the Thunder Basin National Grassland. Mountain
plovers are associated with black-tailed prairie dog colonies on the
Pawnee National Grassland in northern Colorado (Nelson 1993; F. Knopf,
in litt. 1999), in the Arkansas River Valley, and on the Comanche
National Grassland in southeastern Colorado (K. Geisen, CDOW, in litt
2001). A large population of mountain plovers nest in montane
grasslands without prairie dogs in South Park in central Colorado
(Wunder et al. in prep.). About 50 percent of the black-tailed prairie
dog colonies in Colorado occur in nine southeastern counties, which
also report numerous mountain plover sightings (Kingery 1998; L.
Nelson, CDOW, in litt. 2002).
Mountain plovers sometimes nest on white-tailed prairie dog
colonies in Colorado, Wyoming, and Montana (P. Deibert, pers. comm.
2003). Gunnison's prairie dogs occur at the periphery of the mountain
plover breeding range in northern New Mexico and southern Colorado, and
mountain plovers have been documented to nest on their colonies (5 out
of 19 confirmed breeding sites on BLM lands in Taos County were on
Gunnison prairie dog colonies (Hawks Aloft 2001b)). The geographic
extent of mountain plover use of Gunnison colonies appears to be small,
and limited information suggests no close dependence.
Because mountain plovers have no ability to modify their
environment to create suitable nesting conditions, the decline of
prairie dogs can result in the loss of suitable nesting characteristics
in only a few weeks (Dinsmore 2001).
Outbreaks of sylvatic plague occur frequently throughout Montana,
Wyoming, and Colorado on prairie dog colonies in the breeding range of
the mountain plover. Sylvatic plague is an exotic disease to which
prairie dogs have almost no immunity, although recent laboratory
research indicates some isolated resistance to plague in black-tailed
prairie dogs (Rocke, USGS, pers. comm. 2002). However, recently
available population data across a majority of the species' range, that
include many smaller populations (which represents the majority of all
occupied habitat), indicate that occupied prairie dog habitat is more
abundant and more stable than previously thought. The majority of
black-tailed prairie dog populations occur in small, isolated complexes
where the dynamics of disease appear to be fundamentally different than
in larger populations. The reproductive and dispersal capabilities of
the species, as indicated by the distribution, abundance, and trends
data for the species, may be sufficient to counteract, at least
partially, the impacts of a disease that occurs only sporadically in
time and space (Service 2002).
Prairie dog control, principally by poisoning, continues to occur
on private and public lands throughout the mountain plover's breeding
range, although the likelihood of control on public lands is minimized
by Federal agency policies (Service 2002). Black-tailed prairie dog
populations are capable of recovering rapidly from chemical control
efforts that temporarily reduce their numbers (or from other depressant
factors such as disease (Knowles 1986) or drought (Hoogland 1995)).
Mountain plovers may vacate prairie dog colonies following plague
or poisoning because of the rapid deterioration of habitat conditions
(Dinsmore 2001), but we consider plague or prairie dog control to be a
temporary impact on mountain plovers. For example, between 1992 and
1996, prairie dog occupation of colonies in Montana's area of greatest
prairie dog abundance was reduced by as much as
[[Page 53097]]
80 percent as a result of sylvatic plague (J. Grensten, pers. comm.
1998). Mountain plover numbers along prairie dog transects in these
colonies declined from 80 in 1991 to 7 in 1999, but have slowly
increased since 1996 as prairie dog abundance has increased (S.
Dinsmore, in litt. 2000a).
Prairie dog shooting is popular throughout the breeding range of
the mountain plover, and intense, persistent shooting of black-tailed
prairie dogs has been shown to reduce prairie dog abundance, and
perhaps prevent or retard recovery of colonies low in abundance due to
sylvatic plague or poisoning (Vosburgh and Irby 1998; Knowles and
Vosburgh 2001; L. Hanebury, pers. comm. 2003). We believe prairie dog
shooting will continue to occur in areas occupied by mountain plovers.
While it has the potential to degrade or prevent recovery of habitat
and impact mountain plover breeding success, we believe those instances
are localized and infrequent.
New information made available this year from many State and
Federal agencies indicates the quantity of occupied black-tailed
prairie dog habitat has increased in the last several decades (Luce
2003). Given the above summary of prairie dog habitat abundance,
distribution, and threats and the subsequent impact on the mountain
plover, we believe modification of prairie dog habitat is not a
substantial threat to the mountain plover.
Oil, Gas, and Mineral Development in Mountain Plover Breeding Habitat
The development of oil, gas, coalbed methane, and other mineral
resources commonly occurs throughout the breeding range of the mountain
plover. Expedited oil and gas development is a national priority, and a
new interagency task force has been assembled to assist Federal
agencies in their efforts to expedite review and completion of energy-
related projects on Federal lands (Executive Order 13212). However, we
were able to find little documentation that this mineral resource
development poses a current or future threat to mountain plovers.
Numerous current BLM planning documents detail the number of wells,
roads, and other facilities required to accommodate development of
these mineral resources. A summary of these planning documents for
Wyoming shows at least 10 authorized or proposed active natural gas and
coalbed methane projects in known or potential mountain plover nesting
habitat (e.g., Continental Divide/Wamsutter II Natural Gas Project,
Seminoe Road Coal Bed Methane (CBM); Powder River Basin CBM) (P.
Deibert, Service, in litt. 2003). Full build-out of these projects
would result in over 50,000 individual wells, impacting up to 63,000 ha
(155,000 ac), and creating nearly 32,000 km (20,000 mi) of new roads
and 37,000 km (23,000 mi) of new pipelines (P. Deibert, in litt. 2002).
Of these statistics, development of the Powder River Basin CBM alone
will include nearly 40,000 wells and 27,000 km (17,000 mi) of new
roads, affecting about 48,000 ha (118,000 ac) of lands (P. Deibert,
Service, in litt. 2003). The Powder River Basin CBM project covers much
of the black-tailed prairie dog habitat in Wyoming (K. Henke, pers.
comm. 2003). In addition, there are about 14,000 coalbed methane wells
proposed for the Powder River Basin in Montana (P. Deibert, in litt.
2003). Numerous other projects (e.g., Bighorn Basin bentonite mine,
Carbon Basin coal) are proposed or ongoing in Wyoming in areas occupied
by mountain plovers (P. Deibert, in litt. 2003). In Wyoming, over
12,000 coalbed methane wells were drilled by 2001, and the current
development schedule established will result in nearly 40,000
additional wells by 2011.
Another example of increased energy development is Phase I of the
SeaWest Wind Power Project in Wyoming. This wind farm is now
operational and has disturbed 30 ha (70 ac) on the Foote Creek Rim
Mesa, but final build-out calls for 667 to 1,000 wind turbines, that
would permanently occupy 208 ha (515 ac) when complete.
The development of oil, gas, and other energy resources requires
construction of individual project pads, access roads, travel
corridors, pipelines, power lines, and other facilities (Brockway
1992). The degree of impact on mountain plovers from these activities
depends on project size, density, frequency of maintenance and
operation, and proximity to mountain plovers. However, the actual
impact of this development on mountain plovers is unknown.
Energy development has the potential to modify specific nesting,
brood rearing, and foraging habitat characteristics, such as vegetation
height, proportion of bare ground, prey density, and predator regimes
(S. Dinsmore, Mississippi State University, in litt. 2003). Mountain
plovers nest on nearly level ground and often near roads, adults and
chicks often feed on or near roads, and roads may be used as travel
corridors by mountain plovers, all of which make plovers susceptible to
being killed by vehicles (McCafferty 1930, Laun 1957, Godbey 1992,
Knowles and Knowles 2001), although we have no evidence that this has
had an impact on mountain plover population levels.
Energy development also results in soil disturbance, and because
the mountain plover has been described as a ``disturbed prairie''
species (Knopf and Miller 1994), this disturbance could be inferred as
benign or even beneficial to the species. The BLM has standards for
revegetation of disturbed sites, and for control of invasive weed
species along roads, well pads, and other disturbed sites. In the
Powder River Basin of Wyoming, anticipated problems with invasive
species induced by coalbed methane mining have not materialized to any
significant extent (J. Carroll, pers comm. 2003).
About 150 ha (370 ac) of mountain plover habitat at the Antelope
Coal Mine in Converse County, Wyoming, have been affected by mining
disturbance since 1982 (P. Deibert, pers. comm. 1999b). Mountain plover
inventories conducted from 1982 to 2001 have documented the presence of
mountain plovers and broods within and contiguous to the mine permit
area. Although the number of broods on the mine permit area has
declined since 1993, broods are still reported adjacent to the mine
permit area (Thunderbird Wildlife Consulting, Inc. 2003). In Montana, a
mountain plover nesting area near the Pryor Mountains in Carbon County
was recently lost to bentonite mining (C. Knowles pers. comm. 2003). As
many as 51 mountain plovers likely occurred on the Foote Creek Rim wind
power project in Carbon County in southeastern Wyoming in 1994. The
population there has now declined to about 26 (Johnson et al. 2000,
Young and Erickson 2003). While we do not believe that mineral resource
and wind farm development can be considered beneficial to mountain
plovers, their combined impacts do not appear to pose a major threat.
Our consideration of energy development as a listing factor in the
proposed rules contributing to the potential decline of the mountain
plover was based on the magnitude of anticipated development, as well
as on information that existing projects have resulted, or are likely
to result, in the modification of habitat required by nesting mountain
plovers, and on enhanced opportunities for avian and terrestrial
predators. However, because coalbed methane development, although
widespread, has not been demonstrated to be detrimental to mountain
plovers and because other types of energy development are more limited,
we believe the current and anticipated mineral resource development in
the
[[Page 53098]]
breeding range of the mountain plover is not a major threat to their
continued existence.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Prior to the passage of the Migratory Bird Treaty Act in 1918,
mountain plovers were commercially hunted for food. However, this no
longer occurs. Mountain plovers reside on some prairie dog colonies
where recreational prairie dog shooting occurs. Although a few mountain
plover mortalities have been attributed to shooting, this loss is not
thought to be significant. There is no recent evidence that
overutilization is a current threat.
Factor C. Disease or Predation
Disease-related factors are not known to be a direct threat to the
species. However, plovers that breed on prairie dog colonies are
indirectly affected through a modification of habitat when an epidemic
of sylvatic plague reduces numbers of prairie dogs in a colony (see
discussion under Factor A).
Mountain plovers eggs and chicks are the most vulnerable life
stages to terrestrial and avian predation. Potential avian and
terrestrial predators include the prairie falcon (Falco mexicanus),
loggerhead shrike (Lanius ludovicianus), ravens (Corvus corax), swift
fox (Vulpes velox), red fox, ground squirrels (Spermophilus spp.), and
coyote (Canis latrans) (Graul 1975). Predation influences the
productivity of all ground-nesting birds, and nesting success of less
than 50 percent is not unusual. Predation on plover nests on the Pawnee
National Grassland has ranged between 15 and 74 percent from 1969 to
1994 (Graul 1975, Miller and Knopf 1993, Knopf and Rupert 1996). A high
rate of nest predation by swift fox at the Pawnee National Grassland in
1993 and 1994 may have been due to temporarily reduced alternate prey
resources (Knopf and Rupert 1996).
From 1994 to 2003, grasslands on the Pawnee National Grassland have
been burned each year to enhance mountain plover nesting habitat (E.
Humphrey, in litt. 2003). All eight nests monitored on the burn sites
in 1996 were destroyed by swift fox (F. Knopf, in litt. 1996).
Increased predation following burning, as indicated on the Pawnee
National Grasslands, may affect nesting success locally in some years,
but is not a persistent factor throughout the species' range. Nest
predation also occurs in Phillips County, Montana, but is probably not
a significant influence on nesting success at this location (Dinsmore
2001).
On December 17, 2002, we completed conferencing under the Act with
the BLM for proposals to develop oil and gas resources in the Powder
River Basin (M. Long, Service, in litt. 2003). We concluded that
predation by mammalian and avian predators would increase with the
development as proposed, and we recommended conservation measures to
minimize adverse effects. Predation on the small number of nests in the
Powder River Basin will not have an impact on the species rangewide.
There is no evidence to indicate at this time that mountain plovers
are affected by West Nile virus (Knopf pers. comm.).
Factor D. The Inadequacy of Existing Regulatory Mechanisms
Protecting the mountain plover and its habitat is complicated by
its wide geographic range, which includes private and public land, and
numerous State, Federal, and Tribal Land authorities.
Federal Regulations
One regulatory mechanism that currently protects the mountain
plover is the Migratory Bird Treaty Act (MBTA), which prohibits direct
mortality or the destruction of active nests. Other Federal laws that
currently provide for conservation of mountain plovers include the
Federal Land Policy and Management Act of 1976; National Forest
Management Act of 1976; Federal Onshore Oil and Gas Leasing Reform Act;
Federal Insecticide, Fungicide, and Rodenticide Act; and Federal
Agriculture Improvement and Reform Act. Some Federal agencies such as
the BLM or the Forest Service also have adopted policies to require
that their actions not contribute to the declining status of a species.
While Federal land ownership is not a guarantee of species
conservation, Federal jurisdiction over surface resources can make
application of conservation practices easier to implement. The BLM
administers 13 percent of the mountain plover habitat (13,000 ha
(27,000 ac)) in South Park, Park County, Colorado, where 20 percent or
more of the entire mountain plover breeding population is estimated to
occur. The BLM recently produced a conservation assessment to help
guide implementation of future conservation measures for the mountain
plover, including land exchange and consolidation (Granau and Wunder
2001). In that assessment, the Reinecker Ridge State Wildlife Area in
the central part of the county was identified as having excellent
mountain plover breeding habitat and good conservation potential. It is
already under public ownership, primarily through the BLM and Colorado
State Land Board (Granau and Wunder 2001).
The National Forest Management Act requires the Forest Service to
manage habitats for native species. The Service has coordinated with
the Forest Service for over a decade regarding the conservation needs
of the mountain plover on the Pawnee National Grassland in Colorado.
Mountain plovers are now nearly extirpated from this historic
stronghold due to climatic events and changes in grazing management,
and restoration of habitat has not been immediately forthcoming.
Recently, the Forest Service initiated efforts to improve nesting
habitat conditions on the Pawnee (Bedwell, in litt. 2003), although
some recovery plans and recovery objectives will not be fully realized
for several years (S. Currey, in litt. 2002).
The Forest Service has closed the shooting season for black-tailed
prairie dogs on the Thunder Basin National Grassland in Wyoming. While
the reason for the closure was recovery of the endangered black-footed
ferret, the mountain plover stands to gain habitat as prairie dogs
there recover from an epizootic of sylvatic plague.
Two small National Wildlife Refuges (Kern and Pixley) in The San
Joaquin Valley and Carrizo Plain provide some natural and cropland
habitat for wintering mountain plovers (J. Engler, in litt. 1992, 2003;
Knopf and Rupert 1995), although they are not managed specifically for
mountain plovers and some of the former potentially suitable grassland
and shrubland on Kern National Wildlife Refuge has been overwhelmed
with exotic grasses and saltcedar (J. Engler, in litt. 2003). The BLM,
California Department of Fish and Game, and The Nature Conservancy have
developed a management plan for the Carrizo Plain Natural Area that
calls for grazing a 1,850-ha (4,640-ac) BLM allotment by sheep in a
manner that would encourage use by mountain plover (BLM et al. 1995).
Prescribed burning also is called for in the plan and has been
demonstrated to encourage use by mountain plovers (Knopf and Rupert
1995).
International Mechanisms
The mountain plover is designated as a threatened species by Mexico
(S. Jewell, Service, in litt. 2000) a designation that has begun to
provide some awareness of the need for the species' conservation.
Mexico currently has no regulations to protect the habitat of the
mountain plover. The species also
[[Page 53099]]
was designated as endangered by Canada in 1987, a status that was
confirmed in 2000 (Committee on the Status of Endangered Wildlife in
Canada 2000).
A Memorandum of Understanding between Canada, Mexico, and the
United States was established to enhance coordination and partnerships
regarding conservation of wildlife, plants, biological diversity, and
ecosystems of mutual interest. The Memorandum of Understanding
established the Trilateral Committee for Wildlife and Ecosystem
Conservation and Management to develop and implement cooperative
conservation projects within the three countries. This Committee has
evaluated opportunities for shared conservation efforts on many
species, including the mountain plover.
State Regulations
The mountain plover is now classified as threatened in Nebraska, a
``species of special interest or concern'' in California, Montana, and
Oklahoma, a ``species in need of conservation'' in Kansas, and a ``high
priority species of concern'' in New Mexico (Flath 1984; Sager 1996; E.
Hunt, California Department of Fish and Game, in litt. 1990; Nebraska
Game and Parks Commission 1992; Oklahoma Department of Wildlife
Conservation 1992; Kansas Department of Wildlife and Parks 1992).
States other than those identified above have not given the mountain
plover any special designation. State listing can encourage State
agencies to use existing authorities to conserve species and habitats,
stimulate research, and allow redirection of priorities within State
natural resource departments.
State agencies within the range of the mountain plover have
recently completed ``A Multi-State Conservation Strategy for the Black-
tailed Prairie Dog in the U.S.'' (Luce 2003) to pursue conservation of
the black-tailed prairie dog through regulations or provision of
incentives to landowners for maintaining prairie dog colonies. The sale
of rodenticide within the mountain plover's breeding range has
increased in recent years and prairie dog shooting also is popular
throughout the range of the mountain plover. No State regulations limit
prairie dog poisoning, but prairie dog shooting is regulated in some
areas. Colorado has banned prairie dog sport shooting on all public
lands and under most circumstances on private lands; Montana has
adopted a seasonal closure of prairie dog shooting on public lands, and
there are no restrictions on shooting prairie dogs in Wyoming, except
on the Thunder Basin National Grassland where shooting is banned.
The State of Colorado, in which a majority of the species' breeding
range occurs, has initiated a program to conserve the mountain plover
and its habitat, by reducing their vulnerability while they occupy
cultivated lands, educating the public, and conserving grasslands that
are known or potential breeding habitat (T. Blickensderfer, Colorado
Department of Natural Resources, in litt. 2003). In 2003, the CDOW
spent $263,000 to conduct research and monitoring on public and private
lands occupied by mountain plovers, create an educational video, and
implement a ``1-877-4PLOVER'' number to help reduce the ``take'' of
mountain plovers on cultivated lands in Colorado and contiguous States.
The CDOW also has created the Colorado Species Conservation Partnership
program. The purpose of the program is to implement conservation
actions on private and public lands throughout Colorado to ensure that
the status of declining and at-risk species is improved to a level that
will prevent their listing under the Act. The CDOW is pursuing mountain
plover conservation under this program by recommending that $2 million
be dedicated to long-term conservation agreements on private lands that
may be occupied by mountain plovers. The initial sign-up for this
effort resulted in applications for conservation easements for over
60,704 ha (150,000 ac) of private shortgrass prairie in eastern
Colorado that would cost $14,600,000. The CDOW is pursuing partnerships
to implement these conservation easements, and is optimistic that more
funding will be provided in future years (R. George, in litt. 2003).
The Nebraska Game and Parks Commission working with the Rocky
Mountain Bird Observatory has initiated a similar landowner incentive
program called the Shortgrass Prairie Partnership (Holliday 2003) and
funded in 2003 for over $500,000. It is in the first stages of
implementation. While both the Colorado and Nebraska programs are
voluntary habitat conservation programs, both wildlife agencies have
the authority to initiate, fund, and implement them. These conservation
efforts are new but have shown some initial successes and are likely to
provide a significant level of protection for the mountain plover,
especially in eastern Colorado.
In California, the species is listed as a species of special
concern. In the following discussion, we describe the regulatory
mechanisms in California on a county-level basis.
Three counties in California are drafting Habitat Conservation
Plans (HCPs) with the Service to protect listed and declining species,
including the mountain plover. With the development of the Western
Riverside County Multiple Species HCP (MSHCP), the County of Riverside
and other jurisdictions within Riverside County and California have
requested an incidental take permit under section 10(a)(1)(B) under the
Act for up to 164 covered species, including the mountain plover. The
permit is needed to authorize take of listed species during urban and
rural development, and agricultural activities in the approximately
509,904-ha (1.26 million-ac) study area in western Riverside County.
The county and other jurisdictions propose in their conservation
strategy to conserve, monitor, and manage 85 percent of the potential
plover wintering habitat (i.e., 2,715 of 3,185 ha (6,710 of 7,870 ac))
in the county. The Service is now assessing the effect of the MSHCP and
the associated incidental take permit on the mountain plover and other
species proposed for coverage.
Similarly, a San Joaquin County HCP finalized in November 2000
targets the protection of over 40,469 ha (100,000 ac) of habitat for 92
species, including the mountain plover, following adoption of enabling
ordinances and/or resolutions by local agencies. A similar HCP for
Solano County, which includes protection of potential mountain plover
habitat, is being drafted, but is not yet finalized.
In summary, Federal, State, and county agencies and governments
have taken significant proactive steps, in the absence of listing, and
have shown progress in the conservation of mountain plovers and their
habitat.
Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence
Natural Factors
Because mountain plovers congregate in large flocks on the
wintering grounds, they may be more vulnerable to local catastrophic
events there. For example, winter surveys in the Imperial Valley in
February 2003 were cut short when heavy rains fell and the flocks of
mountain plovers disappeared. It is speculated that the birds left
their wintering grounds early or moved to less suitable habitats in the
Central Valley (F. Knopf, in litt., 2003). The former appears more
likely since the CBC for the area (Salton Sea South) had a record low
number of plovers, while the Panoche Valley count to the north
[[Page 53100]]
had far greater numbers than usual (birdsource.org 2003).
Pesticide Application and Exposure
Grasshoppers occur throughout the breeding range of the mountain
plover and can reach population levels considered a threat to
agriculture. The APHIS (2002) has authorized rangeland grasshopper and
Mormon cricket control in areas occupied by mountain plovers. Dimilin,
malathion, and carbaryl are the identified chemicals when grasshoppers
reach economic thresholds (APHIS 2002). Control on private lands can be
undertaken by State agencies or private landowners without
participation or oversight by APHIS.
The emphasis of the rangeland grasshopper control program is to
reduce rather than eliminate grasshoppers, but effects to nontarget
insects also occur. The effects of treatment are immediate, and some
treatments can depress insect populations into the second year (APHIS
2003). Grasshoppers and other insects are major prey items of mountain
plovers, and control may influence mountain plover productivity (Graul
1973, Knopf 1996b, Knopf and Rupert 1996). In conferring under section
7 of the Act on the effects of treatments on mountain plover, we
concluded that the application of rangeland grasshopper control as
described by APHIS (2002) on mountain plover breeding habitat could
result in reduced prey, greater foraging distances, increased chick
predation, and reduced survival (W. Knapp, Service, in litt. 2002; R.
Williams, Service, in litt. 2003).
In Montana, grasshopper control is authorized to occur in 2003 on
both public and private lands (APHIS 2003). Because APHIS, in
conference with the Service, has agreed to treatments that will avoid
active black-tailed prairie dog colonies and because mountain plovers
in Montana are closely associated with black-tailed prairie dog
colonies, we believe that treatments are not likely to threaten the
plover there. Similarly, in Wyoming, planning is underway to authorize
grasshopper control on BLM lands throughout Wyoming. After conferring
with the Service, APHIS has agreed to avoid prairie dog colonies and to
avoid known mountain plover nesting sites not associated with prairie
dog colonies (K. Dickerson, Service, pers. comm. 2003). Control on
private lands can be undertaken by State agencies or private landowners
without participation or oversight by APHIS or the Service. While
control of grasshoppers and other pests on private lands may pose a
threat, we do not believe that it is of a magnitude or immediacy that
warrants listing the species.
Mountain plovers may be exposed to pesticides while they occupy
winter habitat in California (Knopf 1996). In conferring under section
7 of the Act, we concluded that malathion application to control curly-
top virus in the Imperial and San Joaquin Valleys would harass some
wintering mountain plovers, but the timing and location of treatment
was not likely to result in direct exposure, or significant impacts to
mountain plover prey (W. White, Service, in litt. 2001b). More
recently, the California Department of Fish and Game conducted an
assessment of exposure risk in Imperial County, specifically, by
comparing mountain plover presence in the Valley with crop types
predominately used by them, and the pesticides typically applied to
these crops (B. Hosea, California Department of Fish and Game, in litt.
2003; Wunder and Knopf 2003). This information suggests that direct
exposure to mountain plovers is reduced because application of
pesticides occurs when plovers are not using the fields. For example,
insecticides are usually applied to alfalfa fields when the alfalfa is
too high to be attractive to mountain plovers. Also, insecticides are
not applied while livestock are grazing fields to minimize pesticide
exposure to livestock, and pre-planting herbicides are usually
incorporated into the soil as a granular form, thus reducing exposure
risk. Potential impacts to the mountain plover prey base on the
wintering grounds are not known, but also appear to be minimal for
reasons cited above (B. Hosea, in litt. 2003). Pesticide exposure by
aerial drift is likely due to mosaic cropping patterns, but effects to
mountain plovers are unknown.
A review of exposure to organochlorines, selenium, and heavy metals
showed that concentrations in mountain plovers were below thresholds
that cause population-level effects (A. Archuleta, Service, in litt.
1997). More recently, the Service analyzed pesticide levels in 20
mountain plover eggs collected from Colorado and 4 from Montana.
Dichlorodiphenyldichloroethylene (DDE) levels were detected in all
eggs; in four eggs levels were above those known to be detrimental to
other bird species (K. Dickerson, Service, in litt. 2002). While the
levels detected in the mountain plover eggs may have been influenced by
prolonged storage prior to analysis, the results nonetheless suggest
that mountain plovers may be at risk from organochlorine pesticide
exposure (K. Dickerson, Service, pers. comm. 2003). The DDE is a
metabolite of dichlorodiphenyltrichloroethane (DDT), known to be
responsible for eggshell thinning, and is extremely persistent in the
environment. In addition, a recent investigation found a wide disparity
in cholinesterase levels between mountain plovers collected in the
Central Valley (pesticide use widespread) compared to those from the
Carrizo Plain (pesticide use minimal), but no differences in mountain
plover body condition (Iko, et al. 2003).
Status Summary
The species was proposed in 1999 and 2002 as threatened because the
best information available at that time indicated breeding population
declines and loss of habitat due to a variety of factors, including
agricultural practices, prairie dog declines, and grassland conversion.
Research on some of these issues, reanalysis of old data, and new
information obtained in the last year lead us to conclude that the
threats to the species are such that listing is not warranted.
There is no information to document that the mountain plover
population is declining or will be in danger of extinction in the
foreseeable future. The declines apparent in the BBS data turned out to
be statistically insignificant. The CBC data in California are
tremendously variable, but suggest a slow downward trend, whereas
surveys on the wintering grounds by researchers do not demonstrate
declines. Although there are many specific instances of grassland
conversion destroying plover nesting habitat, nesting habitat does not
appear to be limiting. Occupied prairie dog habitat is more abundant
and more stable than previously thought, providing breeding and nesting
habitat for plovers. Nesting appears to be equally successful on
croplands as on native grassland. Distribution of plovers across the
wintering range appears to depend more on annual farming practices and
weather rather than on permanent habitat destruction.
In the last few years, Federal land management agencies and State
and county governments have become more actively involved in mountain
plover management. In 1994, the Forest Service developed a ``Mountain
Plover Management Strategy'' for the Pawnee National Grassland in
Colorado. We believe formalized conservation efforts by the CDOW will
improve the status of the mountain plover in Colorado. Other new
conservation efforts within the breeding range include the recently-
established Federal, State, and private High Plains Partnership; the
Department of Defense's Integrated Natural Resource Management Plan for
Fort Carson,
[[Page 53101]]
Colorado; the Rocky Mountain Bird Observatory's ``Prairie Partners'';
The Nature Conservancy's ``Prairie Wings''; and private land
conservation easement efforts in South Park, Colorado.
Other potential conservation measures for this species include--
implementing grazing plans that encourage high grazing intensity in
plover nesting areas, revising county bulletins to include specific
protective measures for the mountain plover during pesticide
application, conducting haying and grazing on existing CRP tracts to
manage for the grass height and density required by nesting plovers,
providing seeding criteria for new CRP tracts that would encourage
establishment of native shortgrass prairie species in preference to
taller grasses, and providing incentives to landowners to leave
cultivated areas unplanted until plover eggs have hatched and chicks
are able to escape from machinery. We have initiated discussions with
the NRCS to explore ways, such as through the Conservation Reserve
Enhancement Program, that these measures might be implemented on
private land.
Following our above analysis and discussion, we have determined
that the action of listing the mountain plover as threatened throughout
its range as proposed in 1999 and 2002 is not warranted. We have made
this determination because the threats to the species, as identified in
the previous proposed rules, are not as significant as earlier
believed, and current available information does not indicate that the
threats to the species and its habitat are likely to endanger the
species in the foreseeable future throughout all or a significant
portion of its range. Consequently, we withdraw our 1999 and 2002
proposed rules and our 2002 proposed special rule for the mountain
plover.
References Cited
You may request a complete list of all references cited in this
document, as well as others, from the Assistant Field Supervisor at the
Grand Junction, Colorado, Field Office (see ADDRESSES).
Dated: September 3, 2003.
Marshall P. Jones, Jr.,
Acting Director, Fish and Wildlife Service.
[FR Doc. 03-22860 Filed 9-8-03; 8:45 am]
BILLING CODE 4310-55-P