Blue-billed white tern

The blue-billed white tern (Gygis candida) is a small seabird found in Pacific and Indian oceans. This species was previously considered as conspecific with the white tern (Gygis alba) and the little white tern (Gygis microrhyncha), but is now recognised as a separate species. It is known as manu-o-kū in Hawaiian. In the Cook Islands, it is known as the kakaia.

Taxonomy

The blue-billed white tern was first formally described by the German ornithologist Johann Friedrich Gmelin in 1789. The species epithet is from Latin candidus (white).

There are two recognized subspecies of the blue-billed white tern -

• Gygis candida candida (Gmelin, 1789) - Indian Ocean - (Seychelles, Mascarene Islands, Chagos Archipelago and Maldives) and tropical Pacific Ocean (Lord Howe Island, Norfolk Island, Kermadec Islands, Hawaii, Clipperton Island, Cocos Island and Malpelo Island)
• Gygis candida leucopes ( and , 1976) - Henderson Island, Pitcairn Island

Description

A medium-sized all-white tern.The eyes are narrow and are dark in colour. The bill is black in color with blue in the base, hence its name. The shape of the bill is thick and "daggerlike" with a sharp-pointed tip. Legs are slaty-blue in color, with yellow or white webs.

The immature is similar to the adult, except the body and wings are fringed with brown and the base of bill is black in colour.

Distribution and habitat

Threats and predation

Giant tortoises have been observed to hunt chicks of this bird on Fregate Island in the Seychelles.

References