Distinguishing Characteristics

Medium-sized, very pale tern with very long, deeply forked tail. Total length 33–41 cm, including 14–23 cm of outer rectrices (tail-streamers); usual mass 95–130 g, egg-bearing females briefly heavier. Wing length 215–240 mm; wingspan about 700 mm. Sexes not distinguishable by any known plumage character, but females have slightly shorter bill than males have. Definitive Alternate (adult breeding) plumage mostly immaculate white with black cap, pale gray wings and mantle, outer 2–4 primaries appearing blackish on upper wing, and long white tail streamers; below white, suffused with pale creamy pink early in breeding season. This pinkish flush, apparent on fresh Alternate plumage, is difficult to see in bright sunlight; it becomes worn or bleached during incubation, and it is usually concealed by white feather-tips. In Definitive Basic (adult nonbreeding) plumage, black cap replaced by black mask extending from eye back to nape, with white forehead and pale streaks on hindcrown, underparts white, and tail shorter.

Adults in Alternate plumage best distinguished from other Alternate-plumaged terns as follows. Shorter wing and longer tail than Common and Arctic terns and plumage paler than in these species and paler even than in Forster’s Tern (S. forsteri). Pure white rather than gray on breast (as in Arctic and Common tern) and less black on wing (black usually confined to outer 3 rather than outer 5 primaries as in Common Tern). No black or dark gray on tail streamers as in Arctic and Common tern. In all plumages, recognizable by lack of black trailing primary edge on all white underwing. Wing-beats faster and shallower than those of Common and Arctic terns. Legs and feet orange red in breeding season, becoming brownish black in winter.

In northeastern birds, bill is black in May, becoming progressively redder from base toward tip during Jun and Jul (Cormons 1976), and blacker again in Aug. In Caribbean birds, bill is one-third to one-half red in May, becoming mostly red during Jun–Jul. Thus at any stage in breeding cycle, bill of Caribbean birds is much redder than at corresponding stage in Northeast, and this resemblance to Common Tern has led to widespread misidentification in the past. (For description of chicks, see Appearance, below).

Juveniles have black bill and legs, blackish head with brown gray forehead, gray or buff upperparts with intricate and variable pattern of black or tan chevrons similar to those of Sandwich Tern. Secondaries and inner webs of primaries whitish; tail nearly all white. These characters distinguish juvenile Roseate from Common and Arctic terns of similar ages (Olsen and Larsson 1995).

In Basic I plumage, immaculate white below, with very pale gray wings and mantle, and brownish black outer primaries. Tail white, with shallow fork. Forecrown white, becoming scaly on crown; nape and hindcrown black, which extends farther forward than on Common Tern. Bill black, but may show some dull red at base. Legs blackish. Adult Basic plumage similar. Legs dull red to blackish. Distinguished from similar Common Tern plumage by wing-tip pattern and entirely white outer tail-feathers.

Distinctive sharp, high-pitched, disyllabic Advertising Call— chi-vik or ki-rik— readily recognizable in both northeastern and Caribbean populations, as well as in European and Australian populations. Even when greatly outnumbered, its voice is readily distinguishable from vocalizations of associated species. Also gives loud rasping call (High-Intensity Alarm Call) when harassing an intruder, leading to the onomatopoeic name carrect in the Lesser Antilles. For other field characters, see Olsen and Larsson 1995 .