Greater Yellowlegs by Barry Van Dusen
An artist who has created many of our covers, Barry Van Dusen lives in Princeton, Massachusetts, and is well known in the birding world. Barry has illustrated several nature books and pocket guides, and his articles and paintings have been featured in Birding, Bird Watcher's Digest, and Yankee Magazine as well as Bird Observer. Barry's interest in nature subjects began in 1982 with an association with the Massachusetts Audubon Society. He has been influenced by the work of European wildlife artists and has adopted their methodology of direct field sketching. Barry teaches workshops at various locations in Massachusetts. For more information, visit Barry's website at http://www.barryvandusen.com.
The Greater Yellowlegs (Tringa melanoleuca) is one of North America's most widespread and easily identified shorebirds. This middle- to large-sized shorebird has long, lemon-yellow legs, distinguishing it from all other shorebirds except for the Lesser Yellowlegs, which is smaller and weighs about half of what the Greater weighs. Greater Yellowlegs has a long, heavy, and slightly upturned bill; Lesser Yellowlegs has a proportionately smaller bill that is shorter, straighter, and more delicate.
In breeding plumage, adult Greater Yellowlegs are gray to brown with whitish spots above, and the head and neck are gray with white flecks. They have white bellies with black barring on the flanks. The nonbreeding plumage is a paler version of the breeding plumage, with the dark flank markings mostly gone. Juveniles are similar in plumage to the nonbreeding adults, but have pale throats and streaking on the breast. The Greater Yellowlegs is monomorphic with no recognized subspecies. It is closely related to the Old World greenshanks, but further study is needed to sort out the relationships.
The breeding range of Greater Yellowlegs stretches from southern Alaska to central British Columbia and in a swath across central Canada south of Hudson Bay to Newfoundland. They winter along both coasts of the United States, the Caribbean Islands, and from Arizona and Texas south through Mexico, Central America, and locally throughout South America. In Massachusetts, the Greater Yellowlegs is a common coastal migrant on salt marshes and mud flats and is sometimes common inland in suitable habitat. It is a rare but regular visitor during winter, primarily on Cape Cod. Yellowlegs arrive from late April to early May and depart beginning in mid-July; fall migration numbers peak from late August until the end of September. They spend their winters in coastal marshes, mud flats, swampy wetlands, and lagoons. Greater Yellowlegs tend to be a solitary species, although in migration they may be found in small flocks. However, when feeding they tend to stay at least 30 feet apart from conspecifics.
The Greater Yellowlegs' most frequent vocalization is a three-note call, often described as whew whew whew or teu teu teu; it is strident, loud, and clear and is often given during flight. When alarmed, they give a series of kek calls while standing. On the breeding territory (and sometimes in migration), the male gives a yodeling flight song during the courtship display, in which the bird flaps its wings as it rises, coasts to a high point, then falls with closed wings some distance before resuming regular flight. On the ground, the courting male runs around the female and raises quivering wings.
Greater Yellowlegs are boreal breeders, nesting in muskeg and other waterlogged ground covered with lichens, mosses, and sedges, as well as in open woodlands and meadows where there are small ponds and sloughs. They also breed on tundra. Lined with sedges, grasses, or leaves, the nest is a well-hidden, shallow scrape in peat, moss, grass, or other substrate, often close to a short boreal tree.
The nesting biology of Greater Yellowlegs is poorly known. The usual clutch of 3–4 dark-spotted gray or olive eggs is incubated for about three weeks until hatching. Adult birds often sit tight on the nest when approached, or they may leave the nest and give a broken-wing distraction display. While nesting, one adult sits on the eggs or stays with the chicks while the other bird perches on a tree in order to spot predators at considerable distance. Predators are harassed or mobbed. Chicks are precocial, capable of leaving the nest and feeding themselves the day they hatch. Both parents remain with the chicks for about a month until they begin to fly. One or both parents continue to accompany the chicks for an additional two weeks until they become capable of sustained flight.
Greater Yellowlegs usually forage in shallow water or on mud flats. Their prey consists of small marine and terrestrial invertebrates, including shrimp, beetles, insect larvae, and small fish and amphibians. In daytime they are primarily visual foragers, stabbing at prey with the bill, but at night and sometimes during the day they use a sweeping motion, which suggests that they are foraging tactilely. They may chase fish and sometimes pursue small fish with the bill open and the lower mandible below the water surface. Occasionally, a small flock will pursue schools of minnows in unison, moving and turning together.
In the late nineteenth and early twentieth centuries, Greater Yellowlegs populations decreased due to market and game hunting activities. There is little information about subsequent trends, but populations seem to have increased and are currently stable. There is little information about predators of Greater Yellowlegs. The vagaries of weather, especially freezing on the breeding grounds, are known to be detrimental. However, Greater Yellowlegs have a broad breeding range that includes a wide variety of habitats. In migration, they do not depend on just a few staging areas, and in winter they use wetlands dispersed throughout Central and South America—all factors that suggest that the Greater Yellowlegs will continue to be one of our more common and conspicuous shorebirds.