NT
Mountain Plover Charadrius montanus



Justification

Justification of Red List Category
This species is classified as Near Threatened due to an ongoing continuous decline resulting from habitat loss and degradation, a consequence of cultivation, urbanisation, over-grazing, and changes in native herbivore populations. Although it has experienced significant past population declines, the rate is currently close to, but does not meet the threshold required to list this species as Vulnerable. Such rates of decline are projected to continue into the future and as such, this species is listed as Near Threatened.

Population justification
Whilst thought to number just 10,000-14,000 mature individuals until relatively recently (2009), estimates have been subject to significant revision and Partners in Flight (2019) now estimate the population to total ~20,000 mature individuals.

Trend justification
This species underwent a large and statistically significant decrease. Recent data from Partners in Flight (2019) suggests a potential annual decline of ~3.11% between 1970-2017, which would equate to a decline of 31% over three generations. However, there is a large margin of error in this estimate and populations are thought to have been stabilising in recent years (T. O'Connell in litt. 2016). The North American Breeding Bird Survey suggests a rate of decline of ~2.5% between 2010-2015, which equates to a decline of ~26% across three generations (Sauer et al. 2017), lower than the 31% suggested over the longer term by Partners in Flight (2019). As a result, the rate of decline is placed in the band 20-29%.

Distribution and population

Charadrius montanus breeds in south Alberta and south-west Saskatchewan, Canada, and Montana, Wyoming (3,400 adults), eastern Colorado (8,600 individuals), Park County in Colorado (2,300 adults), New Mexico, the Oklahoma Panhandle (68-91 individuals), U.S.A. (Knopf 1996, Childers and Dinsmore 2008, McConnell et al. 2009), and potentially >100 individuals in Nebraska (S. Dinsmore in litt. 2016). It has bred in Texas, east Utah (Day 1994) and once in eastern Arizona (Knopf and Rupert 1999), and has apparently been extirpated from former breeding areas in North Dakota, South Dakota, and Kansas (McConnell et al. 2009). All these birds winter from Sacramento, San Joaquin and Imperial valleys, California (Knopf and Rupert 1995, S. D. Earsom and V. B. Estelle in litt. 1999), south to Baja California, Mexico (Wilbur 1987), and irregularly in south Arizona and south Texas in the Blackland Prairie (Knopf 1996, M. Lockwood in litt. 1999). There appears to be some mixing on the wintering grounds, with birds banded in Montana having been documented over-wintering in southern California, southeastern Arizona, and Texas (S. Dinsmore, in litt. 2016). 
Abundant in the 19th century, it declined to an estimated 8,000-9,000 birds in 1995, including a 63% decrease from 1966-1991 (Knopf 1996), but the population is now estimated at 15,000-20,000 individuals (or 18,000-20,000 individuals [Andres et al. 2012]). These figures are likely to reflect an increase in counting accuracy rather than a recent population increase. Breeding was first successful in Nuevo León, Mexico, in 2004 (Gonzales Rojas et al. 2006) following an unsuccessful attempt in 1998 (F. L. Knopf in litt. 1998, 1999, Knopf and Rupert 1999), and in Coahuila in 1999 (Desmond and Ramirez 2002). These and/or northern birds regularly winter at Janos in Chihuahua (P. Manzano in litt. 1998, S. D. Earsom and V. B. Estelle in litt. 1999), with others reported from Sonora to Tamaulipas south to Zacatecas and San Luis Potosí (Howell and Webb 1995a, Gómez de Silva et al. 1996).

Ecology

It nests in heavily grazed, shortgrass prairie, xeric scrub and fallow fields, typically on prairie dog Cynomys spp. colonies (Knowles et al. 1982, Knopf 1996, Knopf and Rupert 1999, Duchardt et al. 2020). It arrives in Canada and northern U.S.A. in late March-April and leaves in early October (Knopf 1996, S. Dinsmore in litt. 2020). Recent work has shown that Montana breeders stop over during fall in Colorado/Kansas en route to wintering areas in the southern U.S.A.; movements north in spring are more direct (Pierce et al. 2017). It is a dietary generalist in winter (Knopf 1998) when it inhabits semi-desert, dry, bare agricultural land and (in Mexico) breeding-type habitats (S. D. Earsom and V. B. Estelle in litt. 1999). In the Imperial Valley (California) wintering flocks show a preference for burnt Bermudagrass fields and grazed alfalfa (Wunder and Knopf 2003). The species apparently fares better during drought years (Dinsmore 2008). It flocks in winter and on migration (S. D. Earsom and V. B. Estelle in litt. 1999).

Threats

Hunting probably explains the long-term decline. More recently, cultivation and urbanisation have reduced nesting habitat, and intensive grazing has resulted in desertification and a reduced prey base (S. D. Earsom and V. B. Estelle in litt. 1999). Large declines in grazing species, especially bison and prairie dogs, have resulted in unsuitable habitat succession (Piersma 1996, Knopf and Rupert 1999). Prairie dogs, which this species is particularly associated with, can be greatly affected by sylvatic plague (Dinsmore and Smith 2010), yet treatment of these species against this can have further detrimental effects on nesting success of the plover (Dinsmore 2013). Furthermore, within- and between-year dispersal distances are generally short (<5 km), suggesting that local scale conservation of prairie dogs may be important (Skrade and Dinsmore 2010). Over 70% of nests on cultivated land are destroyed by farm machinery (Shackford et al. 1999), although Dreitz and Knopf (2007) suggest that nest success is comparable between cultivated land and grasslands - instead the cause of nest failure is different between the two habitat types. Mining activities within its range can have detrimental effects on this species (Andres and Stone 2010).

Conservation actions

Conservation Actions Underway
CMS Appendix II. A Conservation Action Plan for this species was published in 2010 (Andres and Stone 2010). Pawnee National Grassland, Colorado, and Charles M. Russell National Wildlife Refuge, Montana, are important reserves (Shackford et al. 1999). It has been proposed for listing under the Federal Endangered Species Act (F. L. Knopf in litt. 1998, 1999). Black-tailed prairie dog Cynomys ludovicianus has also been proposed, partly because it helps to maintain suitable habitat (F. L. Knopf in litt. 1998, 1999, Duchardt et al. 2020). The release of Black-footed Ferret in Mexico is helping with prairie dog colony protection (B. Leachman in litt. 2003).

Conservation Actions Proposed
Set up a functional Working Group for this species (Andres and Stone 2010). Define Mexican breeding and winter distribution (S. D. Earsom and V. B. Estelle in litt. 1999). Monitor U.S.A. and Canadas populations. Investigate its demography across its range (S. Dinsmore in litt. 2016). Conduct research to investigate how this species may be impacted by energy development projects (Andres and Stone 2010). Improve population estimates by documenting the number of birds nesting away from prairie dog colonies. Research movements of birds (S. D. Earsom and V. B. Estelle in litt. 1999). Protect prairie dog colonies, especially at Janos (S. D. Earsom and V. B. Estelle in litt. 1999, S. Dinsmore in litt. 2016). Restore prairie ecosystems (include protection/reintroduction of grazers). Protect remaining breeding and wintering habitats and prevent further conversion of grasslands. Ensure suitable grassland habitat for breeding mountain plovers by preserving large prairie dogs towns, conducting prescribed burns and implementing heavy grazing when required (Schaffer et al. 2019). Stop agricultural disturbance at nest sites. Train and raise awareness amongst farmers to encourage the protection of this species and its habitat (Andres and Stone 2010). Monitor the extent and health of habitat throughout its range (Childers and Dinsmore 2008). Potentially, future conservation actions for this species may be best targeted at improving chick and adult survival as these factors have been suggested to have a great impact on population growth than nesting success (see Dinsmore et al. 2010). Work to find ways to enforce Mexican wildlife laws to reduce and prevent the direct take of this species (Andres and Stone 2010).

Identification

21-23.5 cm. Pale brown plover. Upperparts brownish grey, underparts whitish washed buff on breast sides and flanks, white forehead and supercilium contrasting with black frontal bar and lores, black bill and long, pale brown-yellow legs. Non-breeding adults lack black on head, have rufous fringes to fresh wing feathers, more extensive and buffy breast markings. Juvenile similar but supercilium buff and broader, more buffy fringes and marked underparts. In flight, looks long-winged and shows white wing-bar, underwing-coverts and in tail. Similar spp. American Golden Plover Pluvialis dominica is larger, darker and greyer, with darker legs and more patterned upperparts, in flight distinguished by white underwing and in tail. Voice Various drawn-out whistles and a sharp kip note.

Acknowledgements

Text account compilers
Everest, J.

Contributors
Benstead, P., Bird, J., Butchart, S., Butcher, G., Dinsmore, S.J., Dreitz, V., Earsom, S.D., Estelle, V.B., Harding, M., Knopf, F.L., Leachman, B., Lockwood, M., Mahood, S., Manzano, P., O'Connell, T., Pilgrim, J., Westrip, J.R.S. & Wunder, M.


Recommended citation
BirdLife International (2022) Species factsheet: Charadrius montanus. Downloaded from http://www.birdlife.org on 22/01/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/01/2022.