Cormorano delle Kerguelen

Identificazione

The Kerguelen shag is 65 cm (25.5 in) long with a wingspan of 110 cm (43.5 in), making it the smallest blue-eyed shag. The adult's upperparts, tail, and thighs are metallic greenish black; the underbody to the throat is white; and the wing linings are brown. Some individuals have white patches on the back and wings. The head and the back of the neck are deep blue or purple, except that a black cap reaches below the eye to the chin and ear coverts. The face and throat pouch are dark brown, ornamented with yellow-orange tubercles. The bill is horn-colored or brown; the eyes are hazel. The legs and feet vary from dark brown to dark-blotched bright pink. Breeding adults have a little black erectile crest on the forehead, yellow or orange caruncles (large warts) above the base of the bill, and a bright blue ring around the eye. After the breeding season, the plumage fades, the eye-ring becomes lead-blue, and the caruncles become smaller and duller-colored.<p>Juveniles are dark brown with varying amounts of white underneath and brown iris, bill, and feet. They have no caruncles, and their eye-rings are lead-blue. They acquire adult plumage gradually.<p>Unlike many cormorants, this species does not spread its wings when it is perched.

Tassonomia

This species has been placed in genera Halieus, Hypoleucos, Notocarbo, and Leucocarbo. Others place it in the genus Phalacrocorax. It has been considered conspecific with some other blue-eyed shags under the name imperial shag. Here it is considered a separate species following the Handbook of the Birds of the World and other authorities<p>It has been suggested that Heard shags may visit the Kerguelens and that Kerguelen shags with white wing or back patches are the result of hybridization.

Nome scientifico

Leucocarbo verrucosus

Autorità

(Cabanis, 1875)

Ordine

Suliformi

Famiglia

Phalacrocoracidae

Genere

Leucocarbo

Areale e habitat

This species nests on the coast of Grande Terre (the main island of the archipelago), on offshore islands, and on islands in the Golfe du Morbihan. It forages at sea throughout the archipelago, usually within 6 km (3.7 mi) of shore and especially in bays and inlets, though immatures have been seen rarely as far as 80 km (50 mi). Reports from Heard Island and western Australia may be of ship-assisted birds.<p>In the austral summer it feeds among kelp, sometimes at the bottom.

Migrazione

Complete migrants

Conservazione

Tendenza della popolazione

unknown