Annet is considered to be of outstanding importance as a seabird colony. Twelve species nest here, of which two, European storm–petrel ("Hydrobates pelagicus") and lesser black-backed gull ("Larus fuscus") have nationally important breeding populations. The storm–petrel breeds amongst the boulders of the more stable storm beaches. The largest population of Manx shearwater ("Puffinus puffinus") in the islands breed here and the other annual breeding species are puffin ("Fratercula arctica"), greater black-backed gull ("Larus marinus"), razorbill ("Alca torda"), kittiwake ("Rissa tridactyla"), fulmar ("Fulmarus glacialis"), herring gull ("L. argentatus") and shag ("P. aristotelis"). Common tern ("Sterna hirundo") breed on the island most years as do cormorant ("Phalacrocorax carbo") and very rarely Arctic tern ("S. paradisaea").