Buller's Shearwater
Ardenna bulleri

Conservation status | On some islands, where colonies had been nearly wiped out by feral pigs, shearwaters re-colonized after pigs were eradicated in 1936. Total population estimated at more than 2 million. |
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Family | Shearwaters and Petrels |
Habitat | Open ocean. Tends to concentrate at areas of strong upwelling, or where warm and cool water currents meet, bringing food to the surface. Rarely comes close to shore. Nests on islands with soil suitable for burrows or with crevices among rocky cliffs. |
Photo Gallery
Feeding Behavior
Food is taken at or just below surface of water. Forages by dipping to surface in flight, plunging into water from a few feet above surface, swimming with head submerged, sometimes up-ending with head down and tail up. Rarely dives underwater. May feed at night.
Eggs
One. White. Incubation is by both sexes, roughly 51 days. Young: Both parents feed young, by regurgitation. Period from hatching to departure from nest probably about 100 days.
Young
Both parents feed young, by regurgitation. Period from hatching to departure from nest probably about 100 days.
Diet
Crustaceans, fish, squid. Diet not well known. Near breeding grounds may feed mostly on euphausiid shrimp and other crustaceans. Off California, may eat mostly small fish and squid.
Nesting
Breeds on Poor Knights Islands off North Island, New Zealand. Adults arrive there in September, most eggs laid in late November, young depart in May. Breeds in dense colonies. Adults noisy around colonies at night, may climb up into trees to take flight more easily. Nest: Site is in burrow under tree roots or rocks, or in cave or rock crevice. Both sexes help dig burrow. Nest chamber is lined with leaves, twigs, pebbles. Where birds nest in Maori burial caves, may use human bones as nest material.
Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds
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Migration
Breeding adults move north in May, common in parts of North Pacific in summer, returning to New Zealand waters by September. Seen off Pacific Coast of North America mainly June to November, most common September-October; evidently these are mostly nonbreeders and immatures.

- All Seasons - Common
- All Seasons - Uncommon
- Breeding - Common
- Breeding - Uncommon
- Winter - Common
- Winter - Uncommon
- Migration - Common
- Migration - Uncommon
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Learn moreSongs and Calls
Silent at sea.Learn more about this sound collection.