Migration

Nature Of Migration In The Species

Coastal populations of Snowy Plovers consist of migrants and year-round residents but most inland breeders are migratory. Distances of migratory movements are relatively short. The direction of movement to winter areas may be either northward or southward for Pacific coast breeders, but is northeast/southwest for birds breeding in the interior of western North America. Birds from the western Great Basin winter on the California and Baja California coasts where they comingle with breeders from the Pacific coast. Those breeding in the Great Plains winter on Gulf of Mexico coast.

Timing And Routes Of Migration

See Figure 6. Pacific Coast. Populations consist of both migrants and year-round residents (Warriner et al. 1986). Birds nesting on the Oregon coast have wintered in California as far south as San Diego County (JCW). From central California coast, some birds travel north or south to wintering areas extending from Bandon, OR, to San Carlos, Baja Sur, Mexico (JSW and JCW). Spring migrants arrive in s. Washington in early March (Widrig 1980). At Monterey Bay, CA, females return earlier than males; from 1985-2005, the median dates local breeders were first detected returning after a winter absence was 25 March (n= 249) for females and 4 April (n= 540) for males. While a few individuals of both sexes returned as early as the first week of January, the central 50% (inter-quartile range) of returning females were first seen between 10 March and 9 April and males between 20 March and 16 April (LES). Individuals nesting at >1 coastal location during a single breeding season (Stenzel et al. 1994) may arrive for secondary nesting attempts any time from late Apr through 2 Jul and depart as early as late Apr (JSW and JCW). Most migrant breeders vacate Monterey Bay nesting areas from late Jun to late Oct (JSW and JCW) and winterers from other breeding areas return between 1 Jul-10 Nov ([median 29 Jul, inter-quartile range 19 Jul-20 Aug, n= 56] LES).

Inland, West of Rocky Mtns. Although present year-round in the San Joaquin Valley (SJV), CA, and deserts of s. California, some marked juveniles and adults from SJV migrate to the California coast for winter (Page et al. 1995, JSW and JCW). Birds nesting in the w. Great Basin (OR and CA) migrate to coastal California and west coast of Baja California, but most from e. Great Basin (UT) apparently do not winter along the California coast; they have been located on the west coast of Baja Sur and in Gulf of California (Page et al. 1995). Arrival at w. Great Basin breeding areas begins by late February at Owens Lake (Ruhlen et al. 2006, W. Deane in litt.) and as early as last week of Mar (Alcorn 1988) at more northerly lakes; most birds arrive in Apr and the latest probably not until Jun; males appear to arrive earlier than females (Page et al. 1979). Earliest migrants reach e. Great Basin in mid-Mar. Most arrive in Apr but some not until early Jun; males arrive about 1 wk before females (Paton 1995). Fall migration from Great Basin begins by early Jul. Most birds have departed by beginning of Sep (Paton 1995, M. Stern pers. comm.), although stragglers have been recorded as late as mid-Oct at Great Salt Lake, UT (Paton 1995), and early Nov at Mono Lake, CA, and Fallon, NV (Alcorn 1988, Shuford et al. 1995).

Great Plains. Birds nesting here are migratory with small numbers wintering in nw. Texas, Arizona, and se. New Mexico (Shuford et al. 1995, Elliott-Smith et. al. 2004). Many breeders from the Great Plains probably winter on the Gulf Coast, particularly in Texas and Mexico; R. Boyd (pers. comm.) located 2 marked breeders from Kansas in winter along the Texas coast, and the number of wintering birds on the Texas coast is larger than number of breeders (see Demography and Populations: population status: numbers). Comparison of plover numbers on a winter survey (1,191 in 1997, Mabee et al. 2001) and breeding season survey (182 in 2006, Zdravkovic et al. 2006) suggest the Laguna Madre de Tamaulipas region of Mexico is probably the winter destination of many plovers from the Great Plains.

Birds typically begin arriving in Colorado about mid-Apr (Andrews and Righter 1992), in Kansas and Oklahoma from fourth week of Mar to first week of Apr (Boyd 1972, Hill 1985, Thompson and Ely 1989), and in Texas and New Mexico by mid-Mar (Oberholser 1974, Hubbard 1985, 1987, Conway et al. 2005). Most probably reach Great Plains breeding sites in Apr; migration extends into May (Boyd 1972, Thompson and Ely 1989, Hill 1992). Fall departure begins by mid-Jul and probably extends into Oct, with stragglers occurring until early Nov (Sutton 1967, Boyd 1972, Oberholser 1974, Thompson and Ely 1989, Andrews and Righter 1992, Shuford et al. 1995).

Gulf Coast. In Florida, population appears to be partly migratory and partly resident with some breeders appearing to migrate from the state and others moving to other Florida coastal locations for winter. Surveys in 2002 indicate a breeding population of about 1.5 the number of individuals found in winter (Himes at al. 2006). In Texas the winter distribution overlaps with the breeding distribution and also includes upper part of Texas coast.

Atlantic. Birds are year-round residents in Caribbean and Bahamas (Gorman and Haig 2002).

Migratory Behavior

No information on size of migratory groups, altitude, or speed of migration.

Control And Physiology

No information.

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