Midway Atoll National Wildlife Refuge
Pacific Region
 

Birds of Midway Atoll

Tristram's Storm-petrel / Oceanodroma tristrami

Photo of Tristram's storm-petrel

Description

Medium-sized storm-petrel; length 176–201 mm, wingspan 438–472 mm, mass 34–50 g; tail only slightly notched (may appear almost squared), unlike most other Hydrobatinae, which are more deeply notched. Plumage overall blackish brown with sharply defined narrow white band across “rump” (white lower rump; upper tail-coverts, which have small black tips; and bases of outer rectrices), extending slightly onto lateral under tail-coverts (often visible at rest below wings); slightly paler brownish-gray wing-bar across upper wing-coverts typically not extending to leading edge of wing (wing-bar becomes more prominent with wear).

 

Tristram’s Storm-petrel
Photo credit: Ian Jones/USFWS

 

Midway Population

Tristram’s storm-petrels were extirpated by rats on Midway Atoll. Small numbers of Tristram’s storm-petrels have been seen since the removal of rats in 1997. Due to the difficulty in locating and viewing eggs or chicks in burrows, no successful nests have been confirmed.

Feeding Habits

Feeds by dipping prey from the ocean’s surface on the wing, often pattering the water with its feet. Diet includes fish, squid, coelenterates, crustaceans, and insects.

Breeding

Winter breeders and are nocturnal at nesting colonies. Nests are placed in recesses in rocks, under piles of mined guano, or burrows that they excavate under vegetation. Eggs are
laid between December through February and nestlings fledge by June. Little information on parental care of egg or young.
Last updated: February 3, 2011