Distinguishing Characteristics

Large, bulky Calidris sandpiper (total length about 23–25 cm, mass about 135 g) often found foraging and roosting in large flocks at localized, traditionally used marine sites in nonbreeding seasons. Characteristic calidridine profile (proportionately small head, small eyes, short neck, short tibia, stout tarsus, bill tapering steadily from a relatively thick base to a relatively fine tip, bill length not much longer than head length, and typically probing in a hunched posture). During nonbreeding season, found principally in intertidal, marine habitats, especially near coastal inlets, estuaries, and bays, or along restinga formations (an intertidal shelf of densely-packed dirt blown by strong, offshore winds) in austral South American wintering areas.

Alternate plumage distinctive; rufa ’s breast and belly are characteristically a salmon-red to brick-red color (often slightly faded) with a light-colored lower belly and under tail-covert region. C. c. rogersi very similar, but with more coloration on lower belly and under tail-covert region. C. c. islandica more richly colored, with redder hues than on rogersi or rufa, and with slightly shorter bills, on average. Back-feathers, axillaries, and tertials of all 3 races are generally dark, with light terminal edges (when fresh) and subterminal rust-colored spots, giving an overall russet appearance in the most brightly colored birds (usually males). Females have less distinct eye-lines and light-colored feathers (sometimes with dark, subterminal mark-ings) interspersed among dark salmon-red ventral feathering.

Basic plumage undistinguished; similar between sexes and among subspecies. Plain gray above, with light fringes (when plumage is fresh) on scapulars and median wing-coverts, white tips to greater wing-coverts giving the appearance of a white line running the length of the wing (as is true for virtually all Calidris) when in flight. Rump and lower back-feathers dull white, with dark subterminal chevrons. Underparts dirty white, with faint, dark vertical streaking on upper breast that may extend laterally to the flanks.

In Basic plumage, most easily confused with Basic-plumaged dowitchers (Limnodromus spp.; dorsal plumage slightly darker gray, much longer bill), or Basic-plumaged Dunlins (Calidris alpina; smaller size, bill slightly down-curved at tip, darker gray dorsum). Bill black, legs typically dark gray to black, but sometimes greenish in juvenile and some older birds in Basic plumage.