pardela-escura vs black-vented shearwater

The Sooty Shearwater and Black-vented Shearwater can be distinguished by their plumage and structure. The Sooty Shearwater is uniformly dark, while the Black-vented Shearwater has contrasting dark upperparts and white underparts. Observing the plumage contrast is the most reliable field mark.

Check plumage contrast: Sooty Shearwater is uniformly dark; Black-vented Shearwater shows a clear contrast between dark upperparts and white underparts.

The Sooty Shearwater is uniformly dark brown to sooty gray, lacking any significant contrast between upper and lower parts. In contrast, the Black-vented Shearwater has dark upperparts with a stark contrast to its white underparts, making it appear more two-toned.