Lesser Yellowlegs
Tringa flavipes
The Lesser Yellowlegs is a slender, medium-sized shorebird known for its long, bright yellow legs and thin, straight bill. It breeds across the boreal forest regions of North America and migrates long distances to wintering grounds in Central and South America. In Western Europe, it is a regular but rare vagrant, typically found in shallow wetlands or mudflats. Its plumage is mottled gray-brown above and white below, featuring a distinctive square white rump in flight.
Details
Identification
Long yellow legs, straight black bill (about head length), white rump, fine mottling on the upperparts.
Social behavior
Often found in loose groups with other shorebirds outside the breeding season; territorial during nesting.
Diet
Insects (especially flies and beetles), small crustaceans, mollusks, and occasionally small fish.
Hunting strategy
Active foraging in shallow water or on mudflats; picks prey from the surface or probes shallowly into the substrate.
Overwintering
Migration to tropical and subtropical regions of the Americas.
Ecology
Ecological role
Consumer of invertebrates; serves as prey for raptors and predatory mammals.
Natural predators
Peregrine Falcon, Merlin, weasels, foxes (especially for eggs and chicks).
Competitor species
Other shorebirds such as the Greater Yellowlegs (Tringa melanoleuca) or Wood Sandpiper.
Ecosystem service
Regulation of insect populations in wetland ecosystems.
Threats
Habitat loss due to wetland drainage, climate change, and hunting along migration routes.
Scientific profile
Morphology & ID
Breeding plumage
Upperparts grey-brown with prominent black and white spotting; underparts white with fine dark streaking on neck and breast; flanks often lightly barred.
Non-breeding plumage
Upperparts more uniform grey-brown with less contrast; underparts whiter, with breast streaking significantly reduced.
Juvenile plumage
Similar to non-breeding plumage, but upperparts show fine, pale (buff) spotting on feather fringes; legs often a paler yellow.
Sexual dimorphism
Minimal; sexes are difficult to distinguish in the field (monomorphic), with females being slightly larger on average.
Distinguishing features
Long, bright yellow legs; straight, needle-thin black bill (length approx. 1.5x head length); white rump visible in flight without a wedge-shaped pattern.
Confusion species
Greater Yellowlegs (Tringa melanoleuca) - larger with a stouter, slightly upturned bill; Wood Sandpiper (Tringa glareola) - shorter, greenish-yellow legs and a prominent supercilium.
Bill
Medium length, very thin, straight, and entirely black in color.
Vocalization
Song
A rhythmic, repeated whistling, often described as 'pill-e-wee' or 'tu-wee', delivered during song flight.
Call
A short, usually disyllabic 'tew-tew' or 'tju-tju', softer and less shrill than the call of the Greater Yellowlegs.
Distribution & migration
Breeding range
Boreal zone of North America, from Alaska through central Canada to Quebec and Newfoundland.
Wintering range
Southern USA, Caribbean, Central America down to southern South America (Tierra del Fuego).
Migration details
Long-distance migrant; primarily uses the Central and Mississippi Flyways in North America; regular vagrant in Europe (especially Great Britain).
Habitat
Breeding habitat
Open boreal coniferous forests, muskeg bogs, forest tundra, and damp clearings, often near water bodies.
Foraging habitat
Mudflats, shallow freshwater ponds, lake shores, salt marshes, and flooded agricultural fields.
Breeding biology
Nest construction
A simple, shallow scrape on the ground, sparsely lined with moss, lichen, or dry leaves, usually well hidden.
Eggs
Creamy, buff, or olive-green with bold dark brown and grey spots.
Parental care
Both parents incubate; the female often leaves the young shortly after hatching, while the male tends to them until they fledge.
Diet & behaviour
Diet breeding
Primarily insects and their larvae (dragonflies, beetles, flies) found in wetland habitats.
Diet winter
Small crustaceans, aquatic insects, snails, and occasionally very small fish.
Feeding technique
Active walking in shallow water; picking from the surface or probing in soft mud.
Foraging strategy
Visual searching combined with rapid pecking movements; sometimes lateral sweeping of the bill in water.
Sociality
Territorial during the breeding season; gregarious in flocks during migration and in wintering areas, often with other Tringa species.
Flock behaviour
Often forms dense flocks when roosting; exhibits coordinated flight behavior when disturbed.
Protection & threats
Main threats
Loss of stopover sites due to wetland drainage; climate change (alteration of boreal breeding grounds); hunting pressure in parts of the Caribbean.
Population trend
Decreasing; long-term data (e.g., North American Breeding Bird Survey) show significant population declines.
Conservation measures
Protection and restoration of wetlands along migration routes; population monitoring; international agreements to limit hunting.