Mountain Plover (Charadrius montanus)

Prepared by:  Kevin Hunting, California Department of Fish and Game

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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, Launís 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.

A, B, C, D. Migration: Migration, departure and arrival dates unclear. Generally arrive on Colorado breeding grounds in late March and early April (Graul and Webster 1976) and Montana and Wyoming breeding grounds a few weeks later. They apparently depart for wintering grounds from early August to late October and arrive in California in September through November (Leachman and Osmundson 1990).

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.

III. Migration stop-over needs/characteristics: Unknown

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).

A. Typical breeding densities: Reported population densities in Colorado (Pawnee National Grassland) range between 2.0 and 4.7 birds/ km2 and in Montana (Charles M. Russell National Wildlife Refuge) between 5.8 and 6.8 birds/ km2 (Knopf 1996).

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).

C. Delayed breeding: No information

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.

XII. Clutch size: Graul (1975, 1976) reported typically three eggs per clutch, occasionally 1, 2 or 4 eggs with the reduced number of eggs per clutch, relative to other shorebirds (4), may be an adaptation to raise young in years of limiting food supply.

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:

A. Major food items: In one study in Colorado, 99.7% of dry matter consumed were arthropods of which 60% were Tenebrionid beetles (Baldwin 1971). Bent (1929) states primary food sources are grasshoppers but that crickets, beetles, and flies are also consumed. Olson (1985), in a study of prey and habitat selection in relation to Black-tailed prairie dog (Cynomys ludovicianus) towns, found that major food items (grasshoppers, beetles, crickets, etc.) occurred in greater numbers on prairie dog towns and in areas subjected to moderate, as opposed to heavy, grazing.

B. Drinking: Apparently do not drink free water.

Site Fidelity: No information for breeding grounds. Knopf and Rupert (1995) found low site tenacity by individual birds. Selected wintering locations have been used in successive years, especially in the Imperial and central and southern California coastal valleys (Edson and Hunting 1999, Hunting and Fitton 1999).

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

A. Substrate (species): Barren or very sparse (<10%) cover (Graul 1973, 1975).

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

II. Vegetation surrounding the nest: measurements from 0.04 ha (0.1 acre) plots. A. Canopy cover (averaged densiometer readings): No densiometer data available. In Montana, breeding colonies (n=35) were located in areas supporting about 30% grass, 40% forb, and 65% total vegetative cover (Knowles, et al, 1982). In general, at least 30% bare ground is found at nest sites (Graul 1975, Miller and Knopf 1994).

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:

1.logs: No data

2.grass/sedge: Predominantly blue grama grass (Bouteloua gracilis) and/or buffalo grass (Buchloe dactyloides).
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.

A. Slope: Nests usually located on flat ground with less than 5% slope (Graul 1975)

B. Aspect: n/a

C. Tree DBH: n/a

D. Snags: n/a

E. Distance to water: n/a

III. Landscape factors A. Elevation: Breeding - Western Great Plains and Colorado plateau from 1220 to 2140 meters (approx. 4,000 to 7,200 feet) above MSL. Wintering - variable but generally in valley bottoms below 300 meters (1,000 feet).

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:

IV. Notes

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:
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.

Bent, A.C. 1929. Life Histories of North American Shorebirds, Part Two. Dover Publications, Inc., New York, New York.
Coues, E. 1874. Birds of the Northwest. Govt. Printing Office, Washington D.C.

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.
Grinnell, J., and A.H. Miller. 1944. The distribution of the birds of California. Pacific Coast Avifauna 27:138-139.

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. Masterís 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.
Miller, B.J. and F.L. Knopf. 1993. Growth and survival of Mountain Plovers. J. Field Ornithol. 64: 500-506.

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.
 

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