Appearance

Hatchlings

Completely downy. Ground color of natal down buff or grayish. Underparts unpatterned but more intensely colored on upper chest. Upperparts marked with dark brown or blackish pattern: includes crown patch divided by median light streak, dark line from eye to nape, 2 stripes extending back from near crown, light-centered diamond patch on lower back, and a stripe on each side from flanks to tail (Jehl 1968). Pattern appears to be characteristic of the genus. Numerous dark-tipped down scattered throughout upperparts make markings less distinct than in Bristle-thighed Curlew hatchling (Allen and Kyllingstad 1949).

Juvenal Plumage

Prejuvenal molt complete. No data on timing or sequence. Plumage similar to Definitive Basic (see below), except head and neck darker, median crown stripe often less distinct; wing-coverts, scapulars and tertials with prominent large, pale buff lateral spots and notches; slightly finer streaking on foreneck, breast, and underwing; breast more buff; dark bars on axillaries frequently broken, forming rows of dots (Cramp and Simmons 1983, Hayman et al. 1986).

Basic I Plumage

Prebasic I molt partial. Occurs at wintering area starting Oct–Dec and complete Jan–Apr. Juvenal flight feathers, some tertials, many lesser and most greater upperwing-coverts, and some tail feathers usually retained; thus most yearlings can be identified by heavily worn primaries (Cramp and Simmons 1983). Basic I plumage like Definitive Basic (see below).

Alternate I Plumage

No data.

Basic Ii Plumage

Prebasic II molt complete. Yearlings remain on winter range and begin molt mid-May to mid-Jul (earlier than adults), starting with primaries; complete by late Dec (Johnson 1977, Cramp and Simmons 1983). In Old World, a few start molt of primaries Jan–Mar, then suspend molt in Apr–Jun (Cramp and Simmons 1983). Plumage same as Definitive Basic.

Definitive Alternate Plumage

Definitive Prealternate molt apparently limited or nonexistent (Cramp and Simmons 1983). In Mauritania, about 70% of Whimbrels showed light to moderate body molt in late Mar, 0% showed any molt in Feb or late Apr (n = 24; Zwarts et al. 1990b). Plumage same as Definitive Basic.

Definitive Basic Plumage

Definitive Prebasic molt complete. Occurs primarily Aug–Sep through Nov–Jan (Prater et al. 1977). Birds may begin head and neck or primary molt before migration; completed on wintering areas (Cramp and Simmons 1983). In James Bay, Ontario, birds migrating south were in partial molt of body feathers; molt of wing and tail not observed (Morrison 1984).

Plumage of N. p. hudsonicus described (follows Ridgway 1919). Specific color nomenclature is capitalized; numbers refer to colors described by Smithe (1975). Crown and forehead Fuscous (21) with pale Buff (124) median stripe; prominent eyebrow stripe pale Buff. Median and eyebrow stripes narrowly streaked with Fuscous to Dark Grayish Brown (20). Contrasting Fuscous to Dark Grayish Brown eye stripe. Chin and upper throat dull white to Buff white. Remainder of head and neck through breast pale Buff, streaked with Fuscous to Dark Grayish Brown. Back, scapulars, tertials, rump, and uppertail-coverts Dark Grayish Brown, paler toward edges, fringed and spotted along edges with pale Buff. Secondaries and their upperwing-coverts paler Dark Grayish Brown with more distinct shaft streaks of Dusky Brown (19) and distinct pale Buff margins. Buff markings form rounded notches laterally on longer upperwing-coverts, and deep notches or bars on uppertail-coverts. Rectrices Drab-Gray (119D), barred with Dusky Brown and tipped pale Buff. Primary-coverts Dusky Brown; outer webs of primary remiges Dusky Brown, with 4 innermost spotted pale Buff. Inner webs of primaries Dark Grayish Brown, deeply serrated Pale Pinkish Buff (121D). Belly and median undertail-coverts Buff white, mostly unmarked. Flanks, axillars, and underwing-coverts Pale Pinkish Buff, barred or irregularly marked with Dark Grayish Brown.

Bill

At hatching, dark gray-brown with white egg tooth. In juvenile and adult, bill Dusky Brown, paler at base; base of lower mandible Flesh Color (5). Bill long and slender, decurved over distal two-thirds; decurvature begins 40–60% from base (Mallory 1981).

Iris

Dark brown at all ages.

Legs And Feet

Blue-gray at hatching; in juvenile and adult, dull blue-gray to lead-gray, sometimes tinged olive or greenish (Cramp and Simmons 1983).