Hawaiian Birds and Newell’s Shearwater

Hawaiians called Newell’s shearwater ‘A’o for the moan-like call this seabird emits when in its burrow. The word shearwater comes from the way it hunts for food by skimming close to the surface of the water, then plunging through the waves to catch the fish or squid it spotted from the air. The shearwater seems to slice through, or shear through the ocean spray as it flies in search of food.

The Newell’s shearwater (‘a‘o) is endemic to the Hawaiian Islands, and highly pelagic year-round. It is a fairly small shearwater at 13 inches in length, and adult males and females are dark, sooty brown above, with white throat, white underparts, with the legs and feet that are mainly pale pink. It has a dark bill, with a hooked bill and sharp blades, enabling it to deal with slippery prey easily. Their flight is fast and usually low over water, powered by rapid wing beats interspersed with glides. They often forage in large flocks of mixed species (with wedge-tailed shearwaters, sooty terns, and boobies) following schools of large, predatory fish which drive smaller prey species to the surface. The Newell’s shearwater feed mainly by plunging into the water and swimming using their partly folded wings for propulsion. They can swim underwater, probably down to 10 meters, and swallow multiple prey.

It is named after Brother Matthias Newell, a missionary who worked in Hawaii from 1886 to 1924. Newell’s shearwater breeds only in the Hawaiian Islands: principally Kaua‘i, but also Hawai‘i, and Moloka‘i. It breeds in at least 20 colonies on mountain slopes, and from April to November it can be seen in the waters around the Hawaiian Islands, particularly around Kauaʻi. Although time on shore represents only a small fraction of this bird’s life, the breeding grounds have contributed to its own downfall. Serious population declines are attributed to degraded island habitat, collisions with power lines, fatal attraction to lights, and depredation by introduced land predators. To avoid predation by pigs, mongooses, and cats, nests are found at higher elevations in burrows on steep slopes where they lay a single egg.

more – Hawaiian Birds and Newell’s Shearwater Breeding
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