Appearance
The tern is about 30 cm long with a wing length of 21–23 cm. Their beaks and legs are black, but the tips of their bills are yellow. They have long forked tails. The black-naped tern has a white face and breast with a grayish-white back and wings. The first couple of their primary feathers are gray.There are two listed subspecies:
⤷ "S. s. mathewsi" – islands of the western Indian Ocean
⤷ "S. s. sumatrana" – islands of the eastern Indian Ocean through to the western Pacific & Australasia
References:
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