Wilson’s storm-petrel  (Oceanites oceanicus)

Wilson's storm-petrel is classified as Least Concern (LC) on the IUCN Red List (1).

One of the most numerous of all sea birds (3), Wilson’s storm-petrel (Oceanites oceanicus) is predominantly sooty-black with a white, U-shaped rump. There is a pale bar on the upperwing, and the dark underwing has a paler patch on the underwing-coverts (3).

The wings of Wilson’s storm-petrel are distinctively short and rounded, and its feet can be seen protruding slightly past its square tail when in flight. When gliding close to the water’s surface, Wilson’s storm-petrel appears to ‘jump’ as it repeatedly dips its long legs in the water. This species has a distinctive bright yellow membrane between its black toes, which is thought to attract prey (2). As in other storm-petrels, the female Wilson’s storm-petrel is larger than the male (4).

Two subspecies of Wilson’s storm-petrel are recognised: Oceanites oceanicus exasperatus and the slightly smaller Oceanites oceanicus oceanicus (3).

Wilson’s storm-petrel is extremely wide ranging, visiting all major oceans except the Arctic (3).

Wilson’s storm-petrel breeds around the cold waters of Antarctica, on rocky islets, cliffs and amongst boulder scree. During the southern winter it heads north, and may be seen around small rocky islands in the Atlantic and Indian Oceans (2) (5).

Wilson’s storm-petrel makes nests in burrows or rock crevices, and tends to breed together in loose colonies. The breeding season is around November to December. Each pair lays a single egg, which hatches after an incubation period of around 43 days (2).

The diet of Wilson’s storm-petrel is mostly based on planktonic crustaceans, especially krill, but may also include fish, squid and other molluscs. This species can detect prey by smell, and is known to search out and follow fishing trawlers (2) (6).

Wilson’s storm-petrel uses a wide range of vocal signals to communicate. It is a strong flier and an excellent swimmer, but cannot sustain itself for more than a few steps when walking on land (2).

Due to its fragility on land, Wilson’s storm-petrel only comes to shore at night, to avoid predators such as gulls and eagles. When threatened, Wilson’s storm-petrel may squeak and eject an oily liquid from the stomach in defence (2) (6).

Wilson’s storm-petrel is among the most numerous of all birds. No global threat to this species is known, but it does face competition from commercial fishing, as well as the problem of pesticide and heavy metal contamination of its food sources (2).

No specific conservation measures are currently in place for Wilson’s storm-petrel (2).

View information on this species at the UNEP World Conservation Monitoring Centre.

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Find out more about Wilson’s storm-petrel and its conservation:

• BirdLife International - Wilson’s storm-petrel:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=3969

More information on the conservation of albatrosses and petrels:

• Agreement on the Conservation of Albatrosses and Petrels:
  http://www.acap.aq/en/