Appearance

Molts and plumages poorly studied. Sexes similar in all plumages.

Hatchlings

White down covers head, neck, wings, and remainder of body through first week (McVaugh 1975). Down hair-like and longest on crown (D. Wetherbee in Palmer 1962).

Juvenal Plumage

All feather tracts begin producing white pin-feathers by day 8. At 2 wk, Juvenal feathers emerging at following sites: primaries, secondaries, greater wing-coverts, scapulars, back and abdominal tracts, rectrices. Down still covers head and body, but by day 18 down remains only on forehead, crown, and neck. White Juvenal feathers present on body, wings, and tail and emerging on head and neck by 3 wk. After 3 wk, very little down remains; bird covered in white Juvenal feathers. Fully feathered at 5 wk (McVaugh 1975).

Juvenal plumage entirely white, plumes lacking (see Breeding: young birds, above).

Basic I Plumage

Prebasic I molt partial; includes body feathers but not remiges or rectrices; molt gradual, takes place from shortly after attaining flight to 5 mo of age (Palmer 1962). Basic I plumage entirely white.

Alternate I Plumage

Prealternate I molt partial; does not include Juvenal remiges or rectrices; molt occurs during first winter. Includes acquisition of rudimentary plumes on head, neck, and upperparts; plumes similar to but not as fully developed as Definitive Alternate plumage (Palmer 1962).

Definitive Basic Plumage

Definitive Prebasic molt complete; molt begins during latter part of breeding season and completes by late summer.

Definitive Basic plumage similar to Definitive Alternate plumage except plumes much shorter, with those of the back nearly straight (Palmer 1962).

Definitive Alternate Plumage

Definitive Prealternate molt partial; some body feathers (most notably plumes replaced) but does not include remiges or rectrices. Molt may be complete by Jan (Palmer 1962).

Following plumage description based on Palmer 1962 and examination of specimens. Definitive Alternate plumage entirely white with plumes (or aigrettes) arising from head, lower neck, and scapulars. Crown through back of upper neck with many medium-length filamentous plumes (elongated feathers with long, wispy, noninterlocking barbs). Plumes form a bushy crest on head and are longest, and slightly decurved, on hindcrown and upper nape. Lower neck with many medium-length straight plumes which are about same length or slightly longer than longest head plumes. Scapulars with many (up to 50 or more) long plumes with recurved ends which cover entire posterior upperparts and extend to end of tail or several centimeters beyond tail. Portions of plumage (particularly plumes) may become pale ivory in color. Plumes generally persist through late breeding season.

Hatchlings

At hatching, body skin generally grayish, with pinkish and greenish tints and dark blue area around eyes. Bill pale pinkish gray, becoming darker distally, with black tip, and either yellowish base or dark gray “saddle” at base of upper mandible. By 1 wk, bill black, legs gray but more pinkish or greenish above and toes gray but more greenish to reddish pink above. Mouth lining pale pink, iris pale gray to buffy gray, eye-ring gray; legs always darker than toes; bill gradually darkens to black in some, while becoming yellowish with darker tip in others (which also have yellowish eye-ring and lores). By 34 d, toes yellow-green and iris off-white (McVaugh 1975). For additional details on development of bare part colors from hatchings through the first month, see McVaugh 1975 .

Juveniles

By fledging, bill black, legs dark, becoming paler greenish yellow posteriorly, and feet dull yellowish.

Immatures

By end of Prebasic I molt (5 mo), legs and feet have clear-cut black and yellow pattern.

Adults

Bill jet black, except basal portion of upper mandible (confluent with bare skin of lores) and basal portion of lower mandible (only on lower portion) yellow. Bare skin connecting eyes to bill (lores), and narrow eye-ring bright yellow, becom-ing reddish, pinkish, or orangish for short period during early part of breeding season. Iris yellowish. Legs jet black, feet (and sometimes lowermost tarsus) golden yellow, sometimes with black area on some toes, and often with yellow area along posterior tarsus. During breeding season, legs become solidly black and feet may become more reddish or orangish (Palmer 1962, Massiah 1997).