Wilson's Storm-Petrel vs Townsend's Storm-Petrel

In short

Wilson's Storm-Petrel and Townsend's Storm-Petrel are small, dark seabirds with subtle differences. Wilson's is generally more widespread and often seen 'dancing' on the water surface, while Townsend's is more localized to the Pacific and less frequently observed.

Identification tips

1. Look for the distinctive 'dancing' behavior of Wilson's Storm-Petrel on the water. 2. Note the white rump patch, which is more pronounced in Wilson's. 3. Consider location: Wilson's is more widespread, while Townsend's is more Pacific-centric.

Size

Both species are similar in size, but Wilson's Storm-Petrel may appear slightly bulkier due to its broader wings.

Plumage

Wilson's Storm-Petrel typically has a more uniform dark brown plumage with a distinctive white rump, whereas Townsend's Storm-Petrel can appear slightly grayer with a less contrasting rump patch.

Behaviour

Wilson's Storm-Petrel is known for its unique feeding behavior, often seen pattering on the water surface, while Townsend's Storm-Petrel's behavior is less documented but likely similar.

Habitat

Wilson's Storm-Petrel is a generalist, found in various pelagic zones, while Townsend's Storm-Petrel is more restricted to the Pacific, particularly off southern California.

Voice

Vocalizations are not well-documented for either species in the field, and differences are subtle if present.