Appearance

Common Goldeneyes have one of the simplest sequences of molts and plumages of any duck species. The Definitive molt cycle includes 2 molts per year: a complete Prebasic molt after breeding and a partial Prealternate molt in late fall. In addition, both sexes undergo these molts at about the same time, unlike many duck species. This section was revised and rewritten by Chris Thompson; the authors are indebted to him for his efforts. Color numbers cited below are from Smithe (1975–1981).

Hatchlings

Completely downy. Base color white, clearest on cheeks, throat, breast, and belly; slightly grayish on sides, dorsal spots, wing-patches, and undertail. Pattern color black (N/10YR): purest on hood, nape, winglets, and rump; a bit lighter on yoke (upper back), gray on breast-band; pale brownish gray (silvery) on forehead, blending with dark hood. Upper half of face from a line extending from base of bill below eye to nape dark brown to blackish brown; grayish brown across breast; rest of upperparts including nape same color except for prominent white spots on flanks, wing, scapulars, and sides of rump. Lower half of face, upper throat, and rest of underparts white (Bent 1925, Palmer 1976a, Cramp 1977, Fjeldså 1977, Bellrose 1980, Nelson 1993).

Juvenal Plumage

Development follows that of Buffleheads (Gauthier 1993). Feathers appear first on flanks and scapulars and then on tail at about 20–22 d (Bent 1925). Remiges begin to emerge from sheaths at 23–25 d; belly feathers appear at about 30 d; head, back, and neck feathers appear last. Juvenal plumage is completed by 50–55 d (Palmer 1976b).

Males: similar to Definitive Alternate for female, but head and upper neck gray-brown, lower neck gray, upperparts brown narrowly edged dark gray on mantle and gray-brown on scapulars. Chest sepia, feathers narrowly edged with buff. Flanks gray-brown. Rectrices narrow, notched at tip with bare rachis protruding. Greater-coverts mainly white, some with small black tips; median-coverts vary from being gray-brown with pale gray to whitish tips to being entirely white, forming a wing-patch similar to but duller than that of Definitive females. Other upperwing-coverts gray-brown to dull black. Tertials dull black.

Females: similar to males, but median and lesser upperwing-coverts darker (gray-brown to dark gray); only a few outer coverts in upper row of median-coverts tipped white or pale gray; rarely all tipped white. Greater secondary-coverts usually more extensively tipped black, thereby forming a more distinct black band across base of white secondaries. Both sexes differ from Definitive Basic female in having rectrices and feathers on underparts that are narrower and shorter (Cramp 1977, Carney 1983, 1993).

Basic I Plumage

Extent of Prebasic I molt variable, ranging from a limited partial body molt of head, flanks, and scapulars to a molt of all body plumage and sometimes all rectrices (Cramp 1977); never complete (contra U.S. Fish Wildl. Serv. 1977). Occurs Sep–Nov (Dement’ev and Gladkov 1967).

Both sexes: same as Juvenal plumage except head and neck warmer brown; sides of head often tinged black in males. Chest gray brown, feathers tipped white; flanks gray brown, often mottled pale gray in males (Cramp 1977, Tobish 1986).

Alternate I Plumage

Prealternate I molt may begin as early as Oct, shortly after completion of Prebasic I molt, but usually begins in Nov, rarely as late as Mar (Cramp 1977), typically later in females than in males (Palmer 1976b). Dement’ev and Gladkov (1967) state, probably incorrectly, that this molt does not begin until Apr. Partial to complete body molt, never including rectrices (contra Cramp 1977 and U.S. Fish Wildl. Serv. 1977). May be more limited, on average, than Definitive Prealternate molt (Palmer 1976b).

Males: compared to older males, feathers of crown less elongated, brown bases of head feathers visible; white loral spot may be smaller (Olson in Palmer 1976b); may have some completely black median upperwing-coverts; scapulars and flank feathers longer with broader black edges, tips occasionally mottled gray; feathers of sides of breast sometimes partly and faintly barred gray subterminally (Palmer 1976b, Cramp 1977, Tobish 1986).

Females: typically retain more Juvenal and Basic I plumage than do males (Cramp 1977, Tobish 1986).

Definitive Basic Plumage

Definitive Prebasic molt complete, never partial or incomplete (contra U.S. Fish Wildl. Serv. 1977). In all age classes, flight-feather molt begins and ends earlier in males than in females (Dement’ev and Gladkov 1967). In second-year (SY) birds, molt is more prolonged and variable in timing; males molt from mid-Jun through late Aug; females from early Jul through late Sep, rarely as late as late Nov (Baxter and Rintoul 1916). In older, after-second-year (ASY) birds, males molt from early Jul through late Sep, females from early Aug through early Oct, rarely mid-Nov (Cramp 1977, Bellrose 1980). Females usually begin molt when young are 3–4 wk old (5–6 wk old in early clutches) (Bauer and Glutz von Blotzheim 1969). Flightless for 3–4 wk (Cramp 1977, Bellrose 1980). Early nesters begin molt earlier than late nesters (Bauer and Glutz von Blotzheim 1969, Palmer 1976b). All age-sex classes migrate to staging grounds considerable distances from breeding grounds in order to molt (Dement’ev and Gladkov 1967, Bellrose 1980), i.e., they exhibit molt migration, a common phenomenon in waterfowl.

Both sexes: similar to Definitive Alternate female, but head and upper neck dark brown with some black tinge at sides in males, dull brown in females; lower neck gray-brown; mantle, inner scapulars, and flanks dark brown with narrow ash-brown or off-white feather edges. Tertials shiny black.

Males: rectrices black with dark gray cast. Primaries and their coverts black; outermost 2 primaries with narrower web than Juvenal primaries (Palmer 1976b); outermost 4 secondaries black with white tips increasing in size from P1 to P4 and more extensively white on inner than outer web; 7–9 more proximal secondaries entirely white; others may be partially white. Exposed portions of marginal, median, and lesser secondary-coverts completely white; greater secondary-coverts black basally with entire exposed portion of feathers white (Carney 1983, 1993). Thus, most of inner wing is covered with a large white patch. Axillaries and underwing-coverts dark gray, tipped white (Palmer 1976b, Cramp 1977).

Females: tail and wings as in males except marginal and lesser secondary-coverts extensively gray; median secondary-coverts black with white tips; greater secondary-coverts black basally with entire exposed portion of feathers white except for their tips which are black and form a black band across base of white secondaries. Also, females have fewer (5–8) entirely white inner secondaries on average than do males (Palmer 1976b, Cramp 1977, Carney 1983, 1993, Univ. Washington Burke Mus.).

Definitive Alternate Plumage

Partial to complete body molt; probably more extensive and earlier on average than First Prealternate molt; typically begins very shortly after completion of Definitive Prebasic molt; completed in males by late Oct, in females by early Dec (Cramp 1977, Tobish 1986). SY birds undergoing this molt for the first time may not begin molt until Nov, and may not complete it until Feb (Dement’ev and Gladkov 1967).

Males: head and upper neck black, glossed green; large oval (sometimes round) white loral spot between eye and upper mandible; lower neck, upper mantle, sides of breast, and underparts white; thighs mottled brown. Outer webs of elongated feathers on lower flanks broadly edged black. Lower mantle, inner scapulars, back, rump, and uppertail-coverts black. Outer scapulars white centrally, the shorter ones with black outer webs, the longer ones edged black on both webs. Wings and tail of males same as in Definitive Basic plumage (described above); may be sexed accordingly (Palmer 1976b, Cramp 1977).

Females: head and upper neck dark chestnut; lower neck white, mottled gray on lower nape. Upperparts brown-black, broadly edged blue-gray on mantle and inner scapulars; white tips on outer scapulars; rump pale gray. Chest and sides of breast dark gray; flanks gray-brown, feathers tipped white. Thighs and lower vent dark gray mixed with white. Rest of underparts white. Wings and tail of females same as in Definitive Basic plumage (described above); may be sexed accordingly (Palmer 1976b, Cramp 1977).

Bill

At hatching, mandibles dark gray with faint bluish tint; nail dark reddish gray, a bit paler at tip; egg teeth chalky white or yellowish white, lower one opaque (Nelson 1992). Young males: dark olive-brown with yellow-ochre band behind nail similar to adult females, darkening during first winter. Adult males: blue-black. Young females: same as young males but yellow-ochre band brightens to yellow in winter (Cramp 1977). Adult females: can be quite variable in color; typically, distal third of bill, excluding nail, yellow-orange from about Feb to May, becoming duskier in summer at onset of egg-laying (Palmer 1976b). Olson (in Palmer 1976b) stated that most SY males in their first breeding season had “areas of white or gray on the roof of the mouth,” whereas the mouth lining of most older males was entirely black. Roof of mouth largely white or pink in all age classes of females (Palmer 1976b).

Two wintering (Nov) adult females were seen in the U.K. with unusually pigmented bills. One was completely “yellow-orange” except for a “dusky gray area above and behind the nostril” (Allen 1992); the other was “wholly pinkish yellow” (Harrop 1983).

Iris

Gray-brown at hatching with central brown ring of varying width around pupil, usually wider in females, changing successively to purple-blue, blue, and green-blue beginning at 3–20 d and ending by 6–8 wk of age. By 5 mo, a clear pale green-yellow with little or no brown corona around pupil (Palmer 1976b); eyelid rims dark brownish gray (Nelson 1992). Adult males: bright yellow. Adult females: pale yellow to white (Cramp 1977).

Legs And Feet

At hatching, tarsi and toes light olive, greenish gray, or bluish gray; paler and yellower on inner sides of toes, inner web of toe 2, and lobe of hallux (toe 1); pattern and webs olive, grayish olive, or olive-gray (Nelson 1992). Young males: dull yellow-brown to yellow-ochre, webs dark olive-gray. Adult males: yellow-orange with olive-black webs. Young females: same as young males. Adult females: yellow-ochre to pale orange, except webs dull black (Cramp 1977).