Black-winged Petrel vs Blue Petrel

In short

The Black-winged Petrel and Blue Petrel can be distinguished primarily by their wing patterns and tail shapes. The Black-winged Petrel has a distinctive black edge to its wings, while the Blue Petrel features a more uniform blue-gray upperwing with a unique white tail tip. Both species are similar in size, but their plumage and behavior offer clues for identification.

Identification tips

1. Look for the black edge on the wings of the Black-winged Petrel. 2. Note the white tail tip and uniform blue-gray upperwing of the Blue Petrel. 3. Consider the geographic location: Black-winged Petrels are more common in the Pacific, while Blue Petrels are found in sub-Antarctic regions. 4. Observe the flight pattern, though it is similar for both species.

Size

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

Plumage

The Black-winged Petrel has a gray upperwing with a prominent black edge, contrasting with its white underparts. The Blue Petrel is characterized by a blue-gray upperwing and a white tail tip, with a more uniform appearance. The Blue Petrel's underparts are also white, but it has a distinctive dark 'M' pattern across the upperwing.

Behaviour

Both species exhibit typical petrel flight patterns, gliding low over the water with occasional flapping. There are no significant behavioral differences noted in the field.

Habitat

Both species are pelagic, spending most of their time at sea. The Black-winged Petrel is often found in the Pacific Ocean, while the Blue Petrel is more associated with sub-Antarctic waters.

Voice

Vocalizations are not a reliable field mark for these species as they are mostly silent at sea. However, they may call at breeding colonies, which are typically inaccessible.