Blue petrel

The blue petrel (Halobaena caerulea) is a small seabird in the shearwater and petrel family, Procellariidae. This small petrel is the only member of the genus Halobaena, but is closely allied to the prions. It is distributed across the Southern Ocean but breeds at a few island sites, all close to the Antarctic Convergence zone.

The blue petrel's plumage is predominantly blue-grey, with a dark "M" extending across the upperwing from wingtip to wingtip. It has a prominent black cap and white cheeks. It is white below apart from dark patches at the side of the neck. The square tail has a white tip. It has a slender black bill. It is 26–32 cm (10–13 in) in length, has a wing span of 62–71 cm (24–28 in) and weighs approximate 200 g (7.1 oz).