Sterne caugek— Quebec wildlife

The Sandwich tern (Thalasseus sandvicensis) is a tern in the family Laridae. It is very closely related to the lesser crested tern (T. bengalensis), Chinese crested tern (T. bernsteini), Cabot's tern (T. acuflavidus), and elegant tern (T. elegans) and has been known to interbreed with both elegant and lesser crested terns. It breeds in the Palearctic from Europe to the Caspian Sea, and winters in the Mediterranean and on the coasts of Africa, India, and Sri Lanka. The Sandwich tern is a medium-large tern with pale silvery-grey upperparts, white underparts, a yellow-tipped black bill, and a shaggy black crest which becomes less extensive in winter with a white crown. Young birds bear grey and blackish scalloped plumage on their backs and wings. It is a vocal bird. It nests in a ground scrape and lays one to three eggs. Like all Thalasseus terns, the Sandwich tern feeds by plunge-diving for fish, usually in marine environments, and the offering of fish by the male to the female is part of the courtship display.

Description

This is a medium-large tern, 36–41 cm (14–16 in) long with an 95–105 cm (37–41 in) wingspan, which is unlikely to be confused within most of its range. The weight ranges from 200–300 g; males average slightly heavier than females, but with much overlap. The thin, sharp bill is black with a yellow tip. Its short legs are black. Its upper wings are pale grey and its underparts white, and this tern looks very pale in flight, although the primary flight feathers darken during the summer. In autumn and winter, the adult's forehead becomes extensively white after the post-breeding moult in late summer (July-August); the black forehead is regained in the spring moult in February to March. Juvenile Sandwich terns have dark tips to their tails, an all-blackish bill (lacking the yellow tip, but sometimes yellowish at the base) and a scaly appearance on their back and wings, like juvenile roseate terns but with less black on the crown. Cabot's tern is the most similar species to Sandwich tern, sharing the black bill with a yellow tip, but differs structurally, with the bill being obviously stouter, and also differs in moult timing, losing its black forehead earlier in the summer. The primary feathers also differ, with Sandwich tern having a broad white margin on the inner web, grey on Cabot's; this white fringe wears off through the summer, giving Sandwich tern primaries a distinctive 'hook tip' in late summer, while Cabot's primaries remain symmetrical as the grey web is more resistant to wear. Its juveniles also generally lack the scaly pattern of Sandwich tern, being a plainer grey (though this can be confused with first-winter plumage of Sandwich tern). The lesser crested tern and elegant tern differ in having all-orange bills; lesser crested also differs in having a grey rump and marginally stouter bill, and elegant in having a slightly longer, more slender bill.