The Antarctic tern (Sterna vittata) is a small seabird that is distributed throughout the southern hemisphere. In breeding plumage, the Antarctic tern has a black forehead, extending to the crown and back of the neck. The upperparts of the body are pale grey, contrasting with the white rump and white forked tail, and the underparts are generally grey-white, with white undertail coverts. The eyes are brownish-black and the bill and legs are bright red (2) (3).
The non-breeding adult Antarctic tern appears similar, but the forehead is white and the crown is streaked with white. The underparts are whiter outside of the breeding season, and the bill and legs vary from reddish-black to dull red (2) (3).
The juvenile Antarctic tern typically has a white forecrown, streaked with black, and a dark brownish-grey to blackish-grey hindcrown. The upperparts are typically grey with heavy black and buff bars, and white on the underparts with fine black barring. The feathers of young juvenile Antarctic terns usually have scaly dark tips, but these wear quickly and are not present in older juveniles. Year-old juveniles have a white forehead, similar to the breeding adult, as well as white underparts and a dull reddish-black bill (2).
Six subspecies of the Antarctic tern are recognised, which vary in their distribution, size and plumage tone. Sterna vittata gaini is the largest, and also palest, of the subspecies, followed by Sterna vittata tristanensis. Sterna vittata georgiae is the smallest of the six subspecies, but has the longest wings, while Sterna vittata vittata, Sterna vittata bethunei and Sterna vittata macquariensis are all intermediate in size. The nominate subspecies, Sterna vittata vittata, has the darkest plumage (2).
- Sterne couronnée.
- Length: 35 - 40 cm (2)
- Wingspan: 74 - 79 cm (2)
- Average summer weight: 167 - 170 g (2)
- Average winter weight: 197 - 205 g (2)