Cook’s Petrel (Pterodroma cookii)

Identification & Behavior: ~26 cm (10.2 in). The Cook’s Petrel has bluish-gray upperparts with a black “M” pattern on the back. The area around the base of the bill, bellow de eye, throat, breast, and rest of the underparts are white. It has a poorly defined dusky mask across the eye bordered above by a white and reduced eyebrow. It has white outer tail feathers and a black terminal band. The underwing is white narrowly bordered with black. It has a black diagonal stripe from the carpal area, which is often not well-defined. It is very similar to the Stejneger’s or Masafuera Petrel but is distinguished by having a cap concolor with the back (blackish in Stejneger’s) and the lack of broad and somewhat darker semi-collar, which is present in the Stejneger’s Petrel. Also, see the much larger Juan Fernandez Petrel.

Status: The Cook’s Petrel is a rare non-breeding visitor during the winter months of June through October. Due to similarities, extreme caution needs to be used when identifying Pterodroma petrels. The Cook’s Petrel also occurs in Ch.

Name in Spanish: Petrel de Cook.

Sub-species: Cook’s Petrel (Pterodroma cookii), (G. R. Gray), 1843.

Meaning of Name: Pterodroma: Gr pteron= wing and dromos= -racer, runner. cookii: In honor of Capt. James Cook (1728-1779) Royal Navy, hydrographer, explorer and circumnavigator.

See more of the Family Procellariidae