Great Shearwater vs Sooty Shearwater

In short

Great Shearwater and Sooty Shearwater can be distinguished primarily by plumage and structural differences. The Great Shearwater has a distinctive dark cap and a brown belly patch, while the Sooty Shearwater is uniformly dark. Both species are similar in size, but their underwing patterns and overall coloration are key identifiers.

Identification tips

1. Look for the dark cap and brown belly patch of the Great Shearwater. 2. Note the uniform dark coloration of the Sooty Shearwater. 3. Check the underwing: Great Shearwater has a white underwing with brown markings, while Sooty Shearwater's underwing is uniformly dark. 4. Consider the time of year and location, as Great Shearwaters migrate north in April and May, while Sooty Shearwaters have a more widespread distribution.

Size

Both species are similar in size, with no significant differences that are easily observable in the field.

Plumage

The Great Shearwater has a dark cap, white underparts with a brown belly patch, and a white underwing with variable brown markings. In contrast, the Sooty Shearwater is uniformly dark gray-brown, including the underwing, lacking the contrasting patterns seen in the Great Shearwater.

Behaviour

Both species exhibit similar flight patterns typical of shearwaters, with long glides and few wingbeats. Behavior is not a reliable differentiator between these two species.

Habitat

Both species are pelagic and are often found in similar oceanic habitats. They can be seen in large flocks during migration and feeding.

Voice

Vocalizations are not typically used to differentiate these species in the field, as both are generally silent at sea.