Rothschild's Swift vs Sooty Swift

In short

Rothschild's Swift and Sooty Swift are nearly indistinguishable in the field by plumage alone, both being entirely mid-brown. Distribution is the most reliable way to differentiate them, with Rothschild's Swift primarily in northwest Argentina and possibly Bolivia, while Sooty Swift is more widespread in South America.

Identification tips

• Distribution: Rothschild's Swift is found in northwest Argentina and possibly Bolivia, while Sooty Swift is more widespread in South America.
• Plumage: Both are mid-brown; rely on location rather than appearance.

Note: Separation by plumage in the field is considered nearly impossible (Birds of the World).

Plumage

Both species are entirely mid-brown, making them very similar in appearance. There are no distinguishing plumage marks noted between them.

Habitat

Rothschild's Swift is largely confined to northwest Argentina and possibly Bolivia, whereas Sooty Swift has a broader range across South America.