Tuatara: Volume 21, Issues 1 and 2 (New Zealand Albatrosses and Petrels: an Identification Guide)
34. Cook's Petrel — (Pterodroma cooki) — Plate 15
34. Cook's Petrel
Field Characters: 66/28. A small gadfly petrel with pale grey upperparts and black open ‘M’ marking across the dark grey wings. Forehead and lores white, mottled with grey; black stripe under eye. Underparts all white except for a faint broken leading margin to the underwing.
Bill black, slender and rather long; feet pale mauve with black outer toes.
Differs from the other Cookilarias by its uniformly pale head and back and lack of prominent underwing pattern. Cannot be distinguished from Pycroft's Petrel (35) at sea.
The high speed, dashing flight is distinctive, with swooping, high banking and soaring low to the sea characteristic. Does not rise high above the ocean in sustained glides into the wind as some other members of this group. Does not follow ships.
Breeds at Little and Great Barrier Islands in the Hauraki Gulf and at Codfish Island, Foveaux Strait. Migrates to North Pacific for the southern winter.