The
Cook's Petrel is one of the smallest Petrel species in the world. They
likely used to breed across many parts of New Zealand, but now have an
extremely small breeding range, nesting on just three islands near New
Zealand. However, they disperse widely across the Pacific basin
outside of the breeding season, and are regular visitors well offshore of
the West Coast of North America. The accidental introduction of rats and
cats to nesting islands decimated breeding populations in the 20th century,
leading the bird to be considered endangered. However, active efforts
to eliminate predators on their breeding grounds has led to increased
breeding success, and numbers of Cook's Petrels are now increasing again.
Habitat: Found on a few forested islands near New
Zealand when breeding. Outside of the breeding season, they are
pelagic, and are typically found well offshore, only very rarely being seen
close to shore.
Diet: Feeds mostly on small fish, squid, and
crustaceans.
Behavior: Forages by flying low over the water's
surface, dipping down to grab prey items when spotted. They will also
sometimes grab food items with their bill while swimming on the ocean's
surface.
Nesting: The nest of a Cook's Petrel is a burrow
with a nesting chamber, typically built on steep forested slopes on their
nesting islands near New Zealand. The female lays a single egg, and
both parents help to incubate it. Upon hatching, both parents help
feed the nestling.
Song: Usually silent away from breeding colonies.
Has a series of high-pitched calls made on breeding grounds.
Migration: Breeds in a very limited range, on
three islands near New Zealand. Outside of the breeding season,
they disperse widely across the Pacific, ranging as far north as the
Aleutian Islands, with most birds found well offshore in the eastern
side of the Pacific, from North America to South America.
Similar Species:
In range, most likely to be confused with the Mottled Petrel or Stejneger's
Petrel
Conservation Status: Until recently, the IUCN
listed this bird as "Endangered", as populations were in a very sharp
decline. The primary reason was that introduced predators such as rats and
cats had infested their nesting islands, and greatly decreased nesting
success. However, with the successful eradication of rats and cats
from their main breeding island, the
IUCN has recently
upgraded the Cook's Petrel status to "Vulnerable".