Midway Population

Approximately 1,000 nesting pairs nest on Sand and Eastern Islands (Harrison, 1990). Wedge-tails breed widely in the tropical and subtropical waters of the Indian and Pacific Oceans.

Vocalization

Loud groans, moans and wails resulted in island residents giving them the name "moaning bird". Vocalizations occur primarily at night in breeding colonies.

Feeding Habits

Wedge-tailed Shearwaters feed during the day singly or in multi-species flocks. Consumes larval forms of goat fish, mackerel scad, and flying squid driven to the surface by schools of predatory fish (e.g., skipjack tuna).

Breeding

Monogamous. Strictly nocturnal over breeding colony. Their courtship ritual begins shortly after arrival in late March. A pair will sit head to head, often near their burrow entrance, vocalizing two-part wailing duets. Returning to the same nest site each year, Wedge-tails nest in shallow burrows, one to two meters in length.

A single, large, white egg is laid in a nesting chamber at the end of burrow. Egg laying occurs throughout the month of June. No relaying will occur if an egg is lost. Incubation period averages 53 days with both parents alternating shifts on the egg, with each shift lasting as long as 12 days.

Chicks hatch during late-July through late August. Parents feed regurgitated squid and stomach oil to chicks. Feeding takes place every 24 hours and is brief visits during the first week. Fledging occurs in approximately 100-115 days. Parent desertion of the chick typically occurs shortly before fledging.