Beskrivelse: Adult. Compared to Bridled Tern, the Sooty has broader and more blackish trailing edge to secondaries, and darker primaries. Note the moulting in the inner primaries. The Sooty Tern has a 10-months (not 12-months) breeding-cyclus - at least in the Seychelles. I don´t know if the shorter breeding-cyclus affects the birds moulting-cyclus as well.