Band-rumped Storm Petrel, Oceanodroma castro

The Band-rumped Storm Petrel, (Oceanodroma castro), also known as the Madeiran Storm Petrel or Harcourt’s Storm Petrel, is a species of storm petrel in the family Hydrobatidae. It is found in the warmer parts of the Atlantic and Pacific Oceans. In the Atlantic, these include the Azores and Madeira; in the Pacific, the Galapagos Islands.

This bird is about 7.5 to 8.25 inches long with a 17- to 18-inch wingspan, and weighs about 1.5 to 1.75 ounces. It is mainly black with an extensive white rump. It has a forked tail and long wings. It is similar in appearance to Leach’s Storm Petrel.

The Band-rumped Storm Petrel nests in colonies close to the sea in rock crevices and lays a single white egg. The rest of the year it remains at sea. It is strictly nocturnal at the breeding site to avoid predation by gulls and skuas. On clear moonlit nights it will remain hidden as well to avoid being noticed. It’s walking ability is limited to short shuffles to the burrow.

Recent discoveries have been made of possible ‘cold season’ and ‘warm season’ populations of this bird, seen at the same nesting sites at different times of the year. There have been differences in the vocalizations and molts as well. However, it could be possible that two distinct subspecies are being witnessed.

This storm petrel feeds by picking up prey items from the water’s surface. Occasionally it will make a shallow dive up to 50 inches below the surface. A recorded depth of 66 inches seems highly unlikely and is probably the result of faulty equipment.

Image Credit: Forest & Kim Starr / Wikipedia (CC Attribution 3.0)