Migration

Migrant. Occurs in high numbers in interior North America in spring and fall and on the Atlantic Coast in fall. Widespread elsewhere in North America during migration, but in relatively low numbers. More numerous in fall than spring on the Pacific Coast. Consequently, primary routes are midcontinental (mostly west of Mississippi River) in spring, and both along the Atlantic coast and midcontinental in fall.

In general, peak numbers occur at stopover sites at the same time in spring but earlier in fall than Greater Yellowlegs (cf. Elphick and Tibbitts 1998). Annual and seasonal variation in numbers at stopover sites has been attributed to changes in local habitat conditions (Veit and Petersen 1993, Skagen and Knopf 1994, C. Siddle in litt.). At stopover sites in interior North America, Lesser Yellowlegs were able to detect suitable habitat (wet mud/shallow water) almost immediately after it became available (Rundle and Fredrickson 1981, Skagen and Knopf 1994).

Spring

See Figure 4 . Northward movement Feb–May.

South and Middle America. Most depart Argentina by Mar and become scarce after early Apr (Myers and Myers 1979). Locally common until mid-Apr in Colombia (Hilty and Brown 1986). Peak movement occurs Mar in coastal Suriname (Spaans 1978) and early Apr in interior Venezuela (Thomas 1987). Common to locally abundant migrant Mar–early May in Costa Rica (Stiles and Skutch 1989).

Caribbean. Regular during spring in low numbers in Bermuda, records from 4 Mar to 28 May (Amos 1991). No spring peak in Puerto Rico, but individuals present until early May (Wunderle et al. 1989).

Western. Migrates early Mar–early May in California (Small 1994); mid-Apr–mid-May in Pacific Northwest (Paulson 1993); late Mar–mid-May in Utah (Great Salt Lake; Paton et al. 1992). In British Columbia, arrives Mar on southern coast and mid-Apr in southern interior, peaks throughout province late Apr–early May (Campbell et al. 1990). At one stopover/breeding site in e.-central British Columbia median date of first arrival 22 Apr (range = 17–27 Apr, n = 9 yr), peak migration late Apr–mid-May (C. Siddle in litt.). First individual (presumed breeder) arrived on 7 May at Old Crow, Yukon Territory during a 1-yr study (Irving 1960). First transients and/or local breeders usually arrive in s. Alaska in late Apr, e.g., median first arrival 27 Apr at Anchorage (range = 11 Apr–3 May, n = 10 yr; T. Tobish and R. Scher pers. comm.). First arrivals at sw. and n. Alaskan breeding areas: 7 May Lake Clark NP (P. Tomkovich pers. comm.); 15 May Anaktuvuk Valley (range = 15–23 May, n = 5 yr; Irving 1960); 19 May Kobuk Valley (J. Grinnell in Bent 1927).

Interior. Migration begins in early Mar in s. Texas (Oberholser 1974). Peaks west of Mississippi River from early Apr in Texas and Louisiana to mid-Apr in N. Dakota and Minnesota (Table 1). Peaks east of Mississippi River from mid-Apr in Mississippi and Alabama to early May in Wisconsin and Michigan. Spring passage occurs over a 4–6 wk period at stopover sites just south of breeding grounds in the Canadian Prairie Provinces: s. Manitoba (Winnipeg), median arrival 19 Apr, peak late Apr–mid-May, median departure 12 Jun (n = 12 yr; S. Holohan in litt.); s. Saskatchewan, arrive mid-Apr, peak late Apr–mid-May (Roy 1996); s. Alberta (Calgary), mean arrival 22 Apr, peak early May; mean departure 24 May (n = 11 yr; J. Steeves in litt.). Median first arrival at nw. Canadian breeding areas (Northwest Territories): 3 May (range = 26 Apr–5 May, n = 5 yr) at Great Slave Lake; 25 May (range = 25–26 May, n = 3 yr) at Horton River (J. Obst and J. Sirois unpubl.).

Eastern. Movement begins Feb in Florida (Stevenson and Anderson 1994). Peak proceeds northward from mid-Apr in Florida to early May in New England (Table 1). Earliest spring arrivals 12 Mar–28 Mar in Massachusetts (Veit and Petersen 1993); 21 Feb at Cape May, NJ (Sibley 1993). Migration at northern Lake Erie in Ontario occurs Apr–early Jun, peaks May (Bradstreet et al. 1977); at Montreal, Québec, median arrival and departure dates 20 Apr and 25 May, respectively (range 30 Mar–25 Jun; n = 12 yr; Holohan 1983).

Fall

See Figure 4 . Southbound movement late Jun–Oct, sometimes into Nov.

Western. Failed breeders leave s. Alaska in late Jun; successful breeders leave in mid-Jul; juveniles late Jul–early Aug (TLT). First adults arrive in British Columbia late Jun, peak in Jul; juveniles arrive in north of province in late Jul and in south mid- to late Aug, most depart Sep–Oct (Campbell et al. 1990). Low numbers of adults migrate through the Pacific Northwest in Jul, juveniles present in higher numbers from late Jul–early Oct (Paulson 1993). Migration in California is dominated by juveniles and occurs early Jul–early Oct (Garrett and Dunn 1981, Small 1994). Migration occurs early Jul to early Sep or later at Great Salt Lake in Utah (Paton et al. 1992); early Jul–mid-Oct, with peak late Jul–early Sep, in Idaho (Taylor et al. 1992).

Interior. Breeders in n. Manitoba begin flocking in mid-Jul and depart by early Aug, most juveniles leave by mid-Aug, although a few remain into Sep (Jehl and Smith 1970). Timing of migration at stopover sites in the prairie provinces: s. Alberta (Calgary), mean first arrival 28 Jun, peak mid-Jul–mid-Aug, most gone by late Sep (n = 9 yr; J. Steeves in litt.); s. Saskatchewan, first arrival late Jun, peak 15 Jul–10 Aug, most gone by mid-Oct (Roy 1996, Smith 1996); s. Manitoba (Winnipeg), median arrival of first adult 25 Jun, mean juvenile arrival 23 Jul, peak mid-Jul–mid-Aug, most gone by late Sep (n = 12 yr; S. Holohan in litt.). Migration begins west of the Mississippi River by early Jul in N. Dakota and Minnesota, peaks throughout this region late Jul–early Sep (Table 1, S. Skagen unpubl.). Begins east of the Mississippi River by mid-Jul in Wisconsin and Michigan, peaks late Aug–mid-Sep in north and mid-Aug–mid-Oct in south (Table 1). Juveniles peak almost 6 wk later than adults in nw. Indiana: mean adult arrival 8 Jul, mean adult peak 29 Jul, mean juvenile arrival 12 Aug, mean juvenile peak 8 Sep (n = 8 yr; Brock 1990). Most migration complete by late Oct in Oklahoma and Texas (Oring and Davis 1966, Oberholser 1974).

Eastern. Adults peak in early Aug and juveniles late Augearly Sep in the Atlantic provinces of Canada south of the Gulf of St. Lawrence (McNeil and Burton 1973). Timing of passage in e. Canada: Ontario (Kingston), early Jul–early Nov, adults peak in early Aug and juveniles in early Sep (Weir and Cooke 1976); Ontario (Lake Erie), early Jul–mid-Oct, peak mid-Jul–mid-Sep (Bradstreet et al. 1977); Québec (Montreal), median arrival 1 Jul, median departure 20 Oct, extremes 25 Jun–20 Oct (n = 12 yr; Holohan 1983); Nova Scotia (Gulf of St. Lawrence at Magdalen Is.), first adults arrive 13 Jul, peak 5–20 Aug, last adults 27 Aug, first juveniles 11 Aug, peak 20 Aug–10 Sep, last 18 Sep; Nova Scotia (160 km east of mainland coast at Sable I.), first adults 15 Jul, peak 15–25 Aug, last 12 Sep, first juveniles 20 Aug, peak 1–15 Sep, last 18 Sep (McNeil and Burton 1973). Migrants arrive late Jun in New England and mid-Jul in the Carolinas and Florida (Table 1). Adults pass through in Jul (earliest 25 Jun) and juveniles in Aug–Sep (earliest 28 Jul) at Cape May, NJ (Sibley 1993). Peak numbers move southward from mid-Jul–late Aug in New England to mid-Aug–mid-Oct in Florida (Table 1).

Caribbean. Common fall transient in Bermuda, adults begin to arrive in early Jul, peak in late Jul–Aug; juveniles arrive after the second week of Aug (Amos 1991). In Barbados, migration occurs mid-Jul–late Sep with peak passage mid-Aug–mid-Sep (Hutt 1991). Common in Puerto Rico by late Jul (Wunderle et al. 1989).

South and Middle America. Migrants reach Mexico and Central America in Jul (Howell and Webb 1995). Most common late Aug–Nov in Panama (Ridgley and Gwynne 1989); Aug–mid-Oct in Costa Rica (Stiles and Skutch 1989); Aug–Nov in Venezuela (Meyer de Schauensee and Phelps 1978). Reach Suriname in Jul (Spaans 1978) and Paraguay in late Aug. Arrive in Argentina in mid-Aug, peak mid-Sep (Myers and Myers 1979).

Routes

Recoveries of banded birds have provided some information on links between midcontinental and eastern fall stopover areas in North America and migration and/or wintering areas in the West Indies, Mexico, and South America. The following records indicate banding location, recovery location, and number of birds recovered: Ontario–Brazil (3), Ontario–Suriname (2), Ontario–West Indies (2), New Jersey–West Indies (1), Wisconsin–West Indies (1); Kansas–Mexico (1), Kansas–Suriname (1), Massachusetts–West Indies (2), Massachusetts–Brazil (1) (BBL). Few data from other seasons: individual banded in May in the Northwest Territories recovered over a year later in the West Indies and bird banded fall 1960 in Trinidad recovered spring 1965 in S. Dakota (ffrench 1991).

Migration routes unknown for individuals from specific breeding populations, but general movement patterns can be inferred from count data and timing. In South America, northbound migrants probably travel along the Atlantic coast and through the interior river valleys of the Western Amazonia Flyway (Antas 1983). Spring abundance patterns indicate that the primary northbound route to the U.S. is from the north coast of South America, across the Gulf of Mexico, to the Gulf states and southern interior plains. This based on absence of peaks in Central America and the West Indies (e.g., Ridgely and Gwynne 1989, Wunderle et al. 1989) and relatively high numbers recorded in the interior plains of the U.S. (Bent 1927, B. Harrington, S. Skagen unpubl.). A recent summary of available data from the North American stopover sites located between 90°W and 120°W longitude revealed that, although Lesser Yellowlegs were widespread in this region in both seasons, most occurred between 90°W and 100°W in the U.S., and between 100°W and 115°W in Canada (S. Skagen unpubl.). Along the Atlantic Coast, Lesser Yellowlegs are uncommon to locally abundant spring migrants as far north as New York (Bull 1985, B. Harrington unpubl.) becoming scarce in New England, Québec, and the Maritime Provinces (Godfrey 1986, Gauthier and Aubry 1996). Majority probably arrive at breeding areas in e. and central Canada via midcontinental route, fewer by Atlantic coast route. Low spring numbers in California, the Pacific Northwest, and British Columbia (Campbell et al. 1990, Paulson 1993, Small 1994) suggest that birds also use midcontinental route to reach western breeding range.

Fall migrants use 2 main migratory routes: many breeders from e. and central Canada fly southeast to staging areas in the Atlantic Provinces of Canada (south of the Gulf of St. Lawrence) and in New England many (similar numbers as in spring) return south along the midcontinental route (Bent 1927, McNeil and Cadieux 1972, B. Harrington, S. Skagen unpubl.). In Canada, Lesser Yellowlegs are particularly abundant in fall along the shores of the St. Lawrence River, on the Magdalen Is., and in the upper reaches of the Bay of Fundy (Hicklin 1987, Gauthier and Aubry 1996). Most migrants moving south from staging areas in e. Canada and New England appear to make a series of short hops along the Atlantic Coast; individuals that are in exceptional condition may make long transoceanic flights to ne. South America and the Lesser Antilles (McNeil and Cadieux 1972). One individual took ≤5 d to travel between Massachusetts and Martinique I. (BBL), a distance of about 3,000 km.

Fall migration routes in western North America poorly known. Uncommon to locally abundant fall migrant throughout most of Alaska and British Columbia (Gabrielson and Lincoln 1959, Campbell et al. 1990); common fall migrant in the Pacific Northwest (Paulson 1993). Some Alaska migrants may travel along coast to British Columbia, as suggested by concentrations (hundreds) seen on Middleton I. in the Gulf of Alaska in late Jul (S. Hatch pers. comm.). More common in southern than northern California (Garrett and Dunn 1981).

In Suriname, first wave of fall migrants continues eastward along coast whereas second wave appears to winter locally (Spaans 1978). Migrants on their way to Paraguay and Argentina probably traverse Brazil by following interior rivers in the Central Brazil and the Central Amazonia/Pantanal Flyways (Antas 1983).

Some important North American stopover sites include Newburyport Harbor, MA (fall); San Bernard National Wildlife Refuge (NWR), TX (spring); Brazoria NWR, TX (spring and fall); wetlands between Duson and Crowley, LA (spring); wetlands between Jennings and Welsh, LA (spring); Catahoula Lake, LA (fall); Belle Glade/Duda Farm, FL (fall); Cheyenne Bottoms Wildlife Management Area, KS (spring and fall) Great Salt Lake, UT (spring); Quill Lakes, Saskatchewan (fall); Sounding Lakes, Alberta (fall); Chautauqua NWR, IL (fall); Union Slough NWR, IA (fall); North Dakota State University, ND (fall); and wetlands in Wells County, ND (fall; Sykes and Hunter 1978, Veit and Petersen 1993, Morrison et al. 1994b, Harrington and Perry 1995, Morrison et al. 1995, S. Skagen unpubl.). Undoubtedly, several more sites important to this species during migration have yet to be identified.

Failed breeders are first to leave breeding areas, followed a few weeks later by successful breeders (females leave before males), and finally, by juveniles 1–2 wk after their parents (TLT). This pattern is reflected at fall staging areas where females tend to arrive before males (McNeil and Burton 1973) and adults before juveniles (e.g., Weir and Cooke 1976, Brock 1990, Hutt 1991). Generally travel in flocks of 3–25, often intermixed with Greater Yellowlegs, Short-billed Dowitchers (Limnodromus griseus), Stilt Sandpipers, and Pectoral Sandpipers (Calidris melanotos). Flock sizes may increase to ≥50 birds (exceptionally to ≥200) during inclement weather (Hutt 1991). Several reports from New England and South America of migrants flying at night or in evening (e.g., Wetmore 1927, Stone 1937); in Barbados, most migrants pass through from dawn to noon (Hutt 1991). One Oct record of an offshore (113 km east of New Jersey) nocturnal flight in which small, tight flocks (10–15 birds) of Lesser Yellowlegs flew low over the water along with thousands of Blackpoll Warblers (Dendroica striata) and smaller numbers of herons, Greater Yellowlegs, and Long-billed Dowitchers (Limnodromus scolopaceus; Brady 1990–1991). Flocks (n = 55) of Lesser Yellowlegs flew a mean of 29 m ± 30 SD above ground level as they migrated through the upper Tanana River Valley, AK, in spring (Cooper and Ritchie 1995).

Migrants heavier in fall than spring. Most fall adults collected at a Gulf of St. Lawrence staging area had fat levels that corresponded to flight range capability of 2,100 km (McNeil and Cadieux 1972). A few individuals were heavier and had the ability to fly about 3,400 km. The authors concluded that the former group would need to stop at intermediate staging areas along the Atlantic Coast on their journey south whereas the latter birds, if they arrested molt, could follow a transoceanic route starting in e. Canada or New England and ending in the Lesser Antilles or ne. coast of South Amer-ica. Spring birds in Venezuela had fat levels that translated into a 1,400 km flight range (max. 2,200 km), which led McNeil and Cadieux (1972) to suggest that northbound migrants fly across the Gulf of Mexico and make landfall in the s. U.S.