WatchList Species Account for Hawaiian Petrel (Pterodroma sandwichensis)

Qualifies for the list as a Red List Species

Photo: USFWS

The Hawaiian Petrel, which nests only in the Hawaiian Islands, was once lumped with the Galapagos Petrel and known as the Dark-rumped Petrel. Once common as a breeding species at several sites on all the main islands in the archipelago, it was recorded few times from 1910 to the 1940s, and some orthnithogists thought it was near extinction. This decrease was brought about by habitat modification, introduction of predators, and diseases transmitted by mosquitoes. In addition, some of the colonies were wiped out by Polynesians who took the nestlings for food, particularly at colonies at lower elevations; many of the colonies were exterminated before the arrival of the Europeans. As a result, its remaining colonies are restricted to remote, high elevation sites, not, apparently, its preferred habitat. On Maui these dry communities, classified as subhumid and subalpine, generally have a vegetative cover of less than 10%, though on Kauai it nests on steep fern-covered slopes.

The largest colony, only 450-650 pairs, is in Haleakala National Park on Maui, though there may be as many as 1,600 pairs in the colonies on Kauai. Small numbers breed on Maua Loa and Mauna Kea on the island of Hawaii. The total population is estimated at 30,000 individuals, though in 1981 it was put at some 70,000. Returning to the same burrow year after year, it goes to its burrow only at night and it can sometimes be seen nearshore at dusk and dawn, especially near Kauai. Recent surveys estimate the population at 20,000 individuals. Long-lived, it lays only a single egg each year, making it vulnerable to population declines. During nonbreeding the bird may range thousands of kilometers from its nesting colonies. It feeds primarily on squid, but also takes fish, crustaceans and plankton found at the surface.

The most serious threat to the bird is the taking of eggs and young by predators, notably feral cats and introduced mongooses, against which the adults are defenseless. National Park Service and Hawaii Division of Forestry and Wildlife biologists run a predator control program at Haleakala Crater on Maui, where up to 60% of breeding failures were caused by these animals. A long-term banding program is underway to provide demographic data on the nesting population there. Predator control efforts on Hawaii are limited due to the remote location of the birds.

At current rates of predation, the southeastern Mauna Loa population may disappear in the near future and, in fact, the species could become extinct in only a few decades if predation is not brought under control. Occasional mortality occurs from collisions with powerlines and fences near colonies and there is a program to shield streetlights during the breeding season of both petrels and shearwaters to prevent this. In addition, volunteers help to recover grounded fledglings for release on the ocean. The future of this species really depends on the success or failure of efforts on the part of the National Park Service to protect it.