Guide to North American Birds
Conservation status Still numerous as a visitor to North American waters. Declining on some of its nesting islands because of the effects of introduced predators, including rats and coatis.
Family Shearwaters and Petrels
Habitat Open ocean. Mainly found well offshore over relatively shallow waters of continental shelf. Rarely seen from shore, and rarely over deep mid-ocean waters. Nests on islands with soil suitable for nesting burrows.
The largest of the shearwaters to be seen commonly off our Pacific Coast, with rather heavy and slow wingbeats, often gliding and wheeling above the waves, especially in windy conditions. May be solitary or mixed randomly with other seabirds, but not seen in pure flocks of its own species. Nesting only on islands off southern South America, it is a common summer visitor to our coastal waters as far north as southeastern Alaska.

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Feeding Behavior

Forages mostly by plunging into water from flight or diving from surface, and swimming short distance underwater with wings spread; also seizes items while swimming on surface. May follow boats for scraps or offal.


Eggs

One. White. Both sexes probably incubate; incubation period not known. Young: Probably fed by both parents during nocturnal visits; age at first flight not known. Young depart nesting islands in April and May.


Young

Probably fed by both parents during nocturnal visits; age at first flight not known. Young depart nesting islands in April and May.

Diet

Includes fish and squid. Diet not well known; in addition to fish and squid, probably eats various crustaceans.


Nesting

Breeding behavior not well known. Nests in colonies on islands far off coast of Chile. Active at colonies mostly at dusk and at night. Adults gather near colonies in September; by October, some two months before eggs are laid, pairs may be resting together in burrows. Mated pairs may call softly in duet, preen each other's head and neck. Nest: Site is in burrow underground, often more than four feet long. Nest chamber may have sparse lining. Most eggs probably laid in early December.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

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Migration

Migrates north after breeding, commonly seen off North America's west coast from May to November, with peak numbers in September. A few seen at other seasons at our latitudes are nonbreeders or immatures.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon

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Songs and Calls

Silent at sea.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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