Prepared by: Kevin Hunting, California Department of Fish and Game
SPECIES: Mountain Plover (Charadrius montanus)
SUBSPECIES STATUS: No subspecies
MANAGEMENT STATUS: federally proposed Threatened and California Species
of Special Concern
RANGE MAPS:
I. Historical distribution and abundance: Grinnel and Miller (1944)
describe the California range as "Chiefly interior valleys and plains at
low altitudes, south from lower Sacramento valley and inner portion of
San Francisco Bay region to Pacific Slopes of southern coast counties and
to Imperial Valley". Based on anecdotal reports and personal communication
with knowledgeable individuals, Laun (1957), depicted the California range,
using a series of location symbols to describe occurrence based on his
research, to include the entire Central Valley south of roughly Sacramento
County, and a broad region encompassing the southern coastal plain and
southern coastal interior valleys. In addition, Laun’s map included location
dots for south Central San Diego County, southeastern Los Angeles County
and the Imperial Valley.
Jurek (1973) described the range as the west side of the Central Valley
from the vicinity of Woodland, Yolo County, to Wheeler Ridge, Kern County;
Carrizo Plain, San Luis Obispo County; and, locally, in broad agricultural
valleys and coastal plains in Southern California, including Imperial Valley.
In 1973, remnant winter concentrations were known to occur in the vicinity
of Woodland, Yolo County; Pacheco Pass, Merced County, western San Joaquin
Valley, Kern County; Carrizo Plain, San Luis Obispo County; and the Imperial
and Antelope valleys, Imperial County.
Mountain plovers are rare in the upper Salinas Valley and are occasional
vagrants along the north coast of California. Individuals have been recorded
as far north as Humboldt Bay and migrants have been reported occasionally
in the southeast desert regions. They formerly wintered in the Santa Clara
Valley, and, rarely, on coastal plains east of San Francisco Bay. Although
reported as an abundant winter visitor on some of the Channel Islands in
the past, they now occur there rarely or irregularly.
Wintering mountain plovers were once abundant on the coastal plains
and interior valleys from Ventura County to San Diego County, including
western Riverside County. They historically wintered on dry plains between
Los Angeles and the Pacific ocean (Coues 1874). Loss of habitat to urbanization
in these areas has restricted the range of these birds to scattered localities
in coastal Orange and San Diego counties and in the San Jacinto Valley.
II. Current breeding distribution: Does not breed in California. Breeds
in shrub-steppe and short-grass prairie landscapes in Montana, Wyoming,
Colorado, New Mexico, Arizona, Texas, Kansas, Nebraska, Utah, and Oklahoma.
The most important breeding areas are in Colorado (Pawnee National Grassland),
Wyoming and Montana (Phillips County).
ECOLOGY: Please be as specific as possible in regards to bioregion (when
possible).
I. Average territory size: Highly colonial and gregarious during breeding
and wintering seasons. No information on territory size during breeding,
but pre-breeding flocks spaced at 6-15 meters (Leachman and Osmundson 1990).
II. Time of occurrence and seasonal movements.
E. Extent of wintering in California: Analysis of Audubon Christmas
Bird Count (CBC) data indicate that over 90% of the North American population
winter in California (Hunting and Fitton 1999). Important wintering areas
include western San Joaquin and outer coastal valleys, southern Sacramento
valley. IV. Nest type: Scrape on relatively flat ground supporting sparse vegetation.
V. Foraging strategy: Flocks range widely in search of large insects
(especially grasshoppers) and other invertebrates (Graul 1975). Prey searching
consists of running or walking along and pausing periodically to look around
(Laun 1957). Prey is captured with a lunge at the end of a short, quick
run. Flock organization is loose, and the movement patterns of flocks and
individuals is highly variable (Knopf and Rupert 1995).
VI. Displays: Often presents distraction displays and feigned wing injury
displays when chicks are young (Laun 1957).
VII. Social Organization: Wintering grounds - gregarious; forming loose
foraging and roosting flocks reported as ranging in size from 4 to 1128
individuals (Hunting and Fitton 1999).
B. Mating system: Mountain plovers exhibit a "rapid multi-clutch" (Graul
1976) breeding system in which, depending upon available food resources,
the female may lay two sets of eggs in relatively rapid succession, the
first being attended to by the male and the second the female. Females
may switch mates between egg sets possibly presenting an advantage to both
males, who might fertilize more than one clutch, and females, in cases
where the original male is not available when the second clutch is ready
for fertilization (Graul 1976). D. Post fledging biology of offspring: Precocial young. Leave the nest
within 3-4 hours post-hatching, and are brooded by the adults for first
few weeks when weather is cool (Laun 1957). Chicks may actively compete
for shade by pecking (Graul 1975). Fledging at 33-34 days (as defined by
flights of 100 meters or more).
E. Post breeding social behavior: No information. VIII. Incubating sex (female/male): Primarily female but exhibits "rapid
multi-clutch" (Graul 1976) breeding system in which, depending upon available
food resources, the female may lay two sets of eggs in relatively rapid
succession, the first being attended to by the male and the second the
female.
IX. Incubation period: Mean of 29 days (28-31 days [Graul 1975]); Synchronous
hatching.
X. Nestling period: Arrive on breeding grounds in Colorado in late March
and early April (Graul 1973, 1975) and Wyoming and Montana in early to
mid-April (Oelklaus 1989, Olson 1985). Egg laying begins in late April
(Leachman and Osmundson 1990 erroneously report early April) and extends
into early June (Bent 1929, Graul 1975).
XI. Development at hatching: Chicks usually dry within 3 hours of hatching,
will pick at various objects during first 24 hours, and may successfully
catch insects by the end of this period (Graul 1975).
XII. Number of broods: Usually a single brood but occasionally (presumably
related to resource availability and weather) a second (Graul 1975, 1976).
XIII. Who tends the young: In single brood situations, the female tends
the young. In double broods, the male attends the first brood and the female
attends the second (Graul 1975).
XIV. Diet:
B. Drinking: Apparently do not drink free water. Timing of Breeding: This category seems redundant.
HABITAT: Variables to be considered when evaluating habitat characteristics.
This section is broken into three subsections; at the nest, vegetation
surrounding the nest, and larger landscape factors . (This section should
be revised to remove obvious bias for riparian and tree nesting species
and species which breed in CA. Also, in most veg. classification systems,
canopy refers to the uppermost vegetative layer which, in some cases, is
not trees. Appears here canopy refers only to trees. I assumed uppermost
layer regardless of form. Also, I vote for considered grass or herbaceous
cover as a distinct layer instead of including it as a component of ground
cover. - kh)
I. Nest Site
B. Height of nest: 0 to -0.02 meters above ground level.
C. Height of plant: n/a
D. Objects/Plants concealing nest: Nests in shallow scrape. Nest often
containing, and eggs maybe partially concealed by, blue grama grass (Bouteloua
gracilis) and/or buffalo grass (Buchloe dactyloides).
E. Percent nest cover: none
F. Average nest tree DBH: n/a B. Average top canopy height: n/a
C. Dominant plant species in canopy: blue grama grass (Bouteloua
gracilis) and/or buffalo grass (Buchloe dactyloides).
D. Average shrub cover: n/a
E. Co-dominant plant species in canopy: n/a
F. Dominant shrub species: n/a
G. Co-dominant shrub species: n/a
H. Average forb cover: See canopy cover above.
I. Dominant forb species:
J. Co-dominant forb species:
K. Ground cover:
2.grass/sedge: Predominantly blue grama grass (Bouteloua gracilis)
and/or buffalo grass (Buchloe dactyloides).
B. Aspect: n/a
C. Tree DBH: n/a
D. Snags: n/a
E. Distance to water: n/a B. Fragmentation: Continuing loss of sparse grasslands in both breeding
and wintering grounds has resulted in substantially fragmented distribution.
In California, loss of native grasslands and natural fire regimes have
forced this species to use presumably sub-optimal agricultural lands (Knopf
and Rupert 1995).
C. Patch size: No data
D. Disturbance (natural or managed): Highly adapted to natural grazing
and fire regimes of the historic great plains and western valleys.
E. Adjacent land use: n/a
F. Climate: Breeding - hot and dry with average annual precipitation
ranging from 30 to 38 cm and mean maximum temperatures of 16°C
(April), 21°C (May), 27.2 °C
(June), and 30 °C (July). Wintering - Cool
and moist with frequent fog and low visibility.
G. Other: SPECIAL FACTORS: Factors influencing occurrence and viability.
I. Brood parasitism: Not applicable.
II. Dietary: Reduced prey levels on wintering grounds may be a secondary
impact of pesticide use.
III. Sensitivity to human-induced disturbance: Wintering - apparent
low sensitivity as surveyors have approached close to foraging flocks without
apparent disturbance. Unknown on breeding grounds, though low disturbance
sensitivity inferred from behavior on wintering grounds.
IV. Pesticide use: Apparent high susceptibility to pesticides and other
contaminants due to proximity to aerial spraying and ground applications
on agricultural lands on both breeding and wintering grounds. Iko, et al
(1997) measured cholinesterase (ChE) levels in Mountain Plovers from fields
in the California central valley, where pesticide exposure events were
known to have occurred within 24-48 hours of sampling (sample), and from
the Carrizo Plain (no pesticide use, control) and found no significant
difference in ChE activity. However, direct impacts from pesticide application
(including physical and physiological effects from concentrating aerosol
contaminants through the complex Charadriid respiratory system, ingesting
contaminated prey, etc.) and indirect effects of reducing the insect prey
base, are suspected as factors in this species range-wide decline.
V. Predators: Prairie falcons (Falco mexicanus) and coyotes (Canus
latrans) are common associates of wintering Mountain Plovers (Hunting
and Fitton 1999) and are likely predators.
I. Exotic species invasion/encroachment: No data
VII. Other/Notes:
POPULATION TREND: Recent analysis of the USFWS Breeding Bird Survey
(BBS) data suggest that Mountain Plover populations have declined at an
annual rate of 3.7% over the last 30 years which represents a cumulative
decline of 63% during the last 25 years (Knopf 1995). Analysis of CBC data
from 1980 - 1997 indicate 85% of nationwide CBC counts reporting Mountain
Plovers were in California and 95% of all birds detected in any year for
all CBC count circles were in California (Hunting and Fitton 1999). The
gregarious nature, clumped distribution, and lack of winter site fidelity
made trend analysis from CBC data impractical.
DEMOGRAPHICS: No data.
MANAGEMENT ISSUES AND OPTIONS: Wintering - Uses nearly barren or very
sparse native grassland, alkali playas, burned or heavily grazed sites,
and plowed or disced agricultural lands for foraging and roosting. While
flock sizes and locations remain relatively constant once migration has
ceased, flock composition may change as individuals move between flocks
(Knopf and Rupert 1995). Therefore, historic sites, which are used regularly
or in successive years, are important in sustaining winter population numbers
and distribution.
Habitat creation is possible with prescribed burning and plowing during
late fall and early winter. Availability of apparently suitable, yet unused,
agricultural habitat suggests factors other than vegetation structure and
composition (prey abundance and availability, availability of micro-habitat
features for cover or roosting) likely affect distribution.
HABITAT AND POPULATION OBJECTIVES: Knopf (1996) estimated the North
American (worldwide) population at between 8,000 and 10,000 individuals.
This estimate was based on the number of birds detected during the 1994
California census conducted by the National Audubon Society and assumptions
relating to detectability and proportion of population wintering in California
.
There are currently no habitat or population objectives for this species.
The principle decline factor for the Mountain Plover is loss of breeding
and wintering habitat. In the early 1900's, large numbers of Mountain Plovers
were reported in California on both grasslands and agricultural lands.
At that time, California supported approximately 8,900,000 ha (22 million
acres) of grasslands with about 20 percent occurring in the central valley
(Moore et al 1990). Currently, grassland habitat has been nearly extirpated
in the San Joaquin valley with less than 60,700 ha (150,000 acres) remaining.
In the intervening period, conversion of grassland habitats to urban and
agricultural uses proportionately exceeded conversion of any other habitat
type (Ewing et al 1988, Moore et al 1990). As a consequence of this loss,
native habitats used by the Mountain Plover have been reduced to less than
4 percent of their original abundance (Knopf and Rupert 1995).
Clearly, grassland habitat conservation and restoration are required
to recover and stabilize Mountain Plover populations. Key locations appear
to be the Imperial Valley south of the Salton Sea, the Carrizo Plain and
native grassland complexes in the southern San Joaquin valley including
the Pixley Preserve.
MONITORING METHODS AND RESEARCH NEEDS: Local Audubon chapters continue
to play a key role in monitoring breeding Mountain Plover populations.
Similarly, Audubon members and the birding community in general have been
active in helping document wintering numbers in California. In California,
this species is not monitored well by large scale, long-term monitoring
programs like the CBC. A crude index of abundance can be derived from census
data collected by the Department of Fish and Game and Audubon (Hunting
and Fitton 1999). However, such an index relies on assumptions about California
distribution and habitat use which are routinely violated. Probably the
most effective means of monitoring the population is sampling of the breeding
ground population in historic high population centers located on public
land where, other than government management activities, habitat impacts
are minimal.
Current research efforts focus on distribution and abundance on breeding
and wintering grounds, effects of pesticides and other contaminants on
wintering birds, and effects of resource extraction activities on breeding
populations. Future research should be designed to 1) determine factors
effecting habitat selection and distribution on the wintering grounds,
2) determine habitat requirements and routes used during migration, and
3) determine population demographic characteristics.
SCIENTIFIC REFERENCES:
Bent, A.C. 1929. Life Histories of North American Shorebirds, Part Two.
Dover Publications, Inc., New York, New York.
Edson, L., and Hunting K. 1999. Current status of the Mountain Plover
in the Central Valley. Cen. Valley Bird Club Bull., Vol. 2, No. 2, pp.
17-25
Ewing, R.A., N. Tosta, R. Tuazon, L. Huntsinger, R. Marose, K., Nielson,
R. Motroni, and S. Turan. 1988. California's forest and rangelands: growing
conflict over changing uses. California Department of Forestry and Fire
Protection. 348 pp with appendices.
Garrett, K. and J. Dunn. 1981. Birds of Southern California: Status
and Distribution. Los Angeles Audubon Society, Los Angeles, California.
Graul, W.D. 1973. Adaptive aspects of the mountain plover social system.
Living Bird:69-94.
Graul, W.D. 1975. Breeding biology of the Mountain Plover. Wilson Bull.
87:6-31.
Graul, W.D. and L.E. Webster. 1976. Breeding status of the mountain
plover. Condor 78:265-267.
Graul, W.D. 1976. Food fluctuations and multiple clutches in the mountain
plover. Auk 93:166-167.
Hunting, K.W., and S. Fitton. 1999 (in litt.). Winter distribution and
habitat use by the Mountain Plover (Charadrius montanus) in California.
Trans. West. Sect. Wildl. Soc. 34.
Iko, William M., A. Archuleta, F. Knopf, and L.R. DeWeese. 1997. Organophosphate
and carbamate exposure and possible cholinesterase (ChE) inhibition in
wintering mountain plovers (Charadrius montanus). In Craig
G., and Mumma, J.W. (Coords.), Mountain Plover Workshop, A Synopsis of
Presentations. Colorado Division of Wildlife, Ft. Collins, CO.
Jurek, R. M. 1973. California shorebird study. Proj. Final Rep., Accelerated
Research Program for Shore and Upland Migratory Game Birds. and Federal
Aid, Proj. W-54-R. Calif. Dep. Fish and Game, Sacramento. 233 pp. + append.
Knopf F.L. and J.R Rupert. 1995. Habits and habitats of Mountain Plovers
in California. Condor 97:743-751.
Knopf, F.L. 1996. Mountain Plover (Charadrius montanus). In
A.
Poole and F. Gill (eds.), The Birds of North America, No. 21. The Academy
of Natural Sciences, Philadelphia, Pennsylvania, and The American Ornithologists'
Union, Washington, D.C.
Knowles, C.J., C.J. Soner, and S.P. Gieb. 1982. Selective use of black-tailed
prairie dog towns by mountain plovers. Condor 84:71-74.
Laun H.C. 1957. A life History study of the mountain plover Eupoda
montana (Townsed) on the Laramie Plains, Albany County, Wyoming. Master’s
Thesis. Univ. of Wyoming. 67pp.
Leachman, B., and B. Osmundson. 1990. Status of the Mountain Plover:
A literature review. U. S. Fish and Wildlife Service, Golden, CO. 83 pp.
Moore, S., J. Winckel, S. Detwiler, S. Klasing, P. Gaul, N. Kanim, B.
Kesser, A. DeBevec, K. Beardsley, and L. Puckett. 1990. Fish and wildlife
resources and agricultural drainage in the San Joaquin Valley, California.
Volume 1. San Joaquin Valley Drainage Program, Sacramento, California.
364+ pp.
Oelklaus, W.F. 1989. Mountain plover status on their current breeding
range-special emphasis on the birds on and near the Antelope Coal Mine
in the souther Powder River Basin, Converse County, Wyoming. Antelope Coal
Company, Nerco Coal Corporation, P.O. Drawer 1450, Douglas.
Olson, S.L. 1985. Mountain plover food items on and adjacent to a prairie
dog town. Prairie Nat. 19:233-238.
3.water: No data
4.leaf litter: No data
5.rock: No data
6.bare ground: See canopy cover above
7.other: Nests usually located near a rock, manure pile, or other conspicuous
object.
Baldwin, P.H. 1971. Diet of the Mountain Plover at the Pawnee National
Grassland, 1970-71. Tech. Rept. 134. Grassland Biome, U.S. International
Biological Program.
Coues, E. 1874. Birds of the Northwest. Govt. Printing Office, Washington
D.C.
Grinnell, J., and A.H. Miller. 1944. The distribution of the birds
of California. Pacific Coast Avifauna 27:138-139.
Miller, B.J. and F.L. Knopf. 1993. Growth and survival of Mountain
Plovers. J. Field Ornithol. 64: 500-506.