Cook's Petrel vs Stejneger's Petrel

Cook's Petrel and Stejneger's Petrel can be challenging to distinguish at sea due to their similar size and flight patterns. However, Stejneger's Petrel is notable for its distinct blackish hood and a well-marked 'M' pattern on the upper side, contrasting with the blue-grey back. Cook's Petrel lacks this hood and has a more uniform grey upper side.

Look for the blackish hood and 'M' pattern on Stejneger's Petrel. Note the more uniform grey of Cook's Petrel. Consider geographic location and migration patterns, especially if observed outside the breeding season.

Both species are similar in size, typical of small petrels.

Stejneger's Petrel has a blackish hood and a distinct 'M' pattern on its upper side, with a blue-grey back. Cook's Petrel lacks the hood and has a more uniform grey upper side.

Both species exhibit typical petrel flight patterns, gliding low over the water with occasional flapping.

Stejneger's Petrel breeds on a small island and migrates to the temperate North Pacific, often near Japan. Cook's Petrel is found in the South Pacific, particularly around New Zealand.