Grey-rumped Swift vs Vaux's Swift

Grey-rumped Swift

Chaetura cinereiventris

Tiny14 gForest

The grey-rumped swift is about 10.5 cm (4.1 in) long and weighs about 17 g (0.60 oz). It has a protruding head, a short square tail, and wings that bulge in the middle and somewhat hook at the end. The sexes are alike. Adults of the nominate subspecies have mostly glossy black upperparts with a wide gray rump and uppertail coverts. Their underparts are a lighter gray than the rump, though darker on the undertail coverts. Juveniles are essentially the same as adults with the addition of pale fringes to many of the wing feathers. Subspecies C. c. Voice: The principal vocalizations of the grey-rumped swift's nominate subspecies are "a bright repeated short 'tsip'" and a "series of 3–4 slightly downslurred burry drawn-out notes 'trrreeew-trrreeew-trrreeew'." The other subspecies' vocalizations vary but are similar to them.

ID text from Wikipedia, CC BY-SA 4.0

Recorded by Niels Krabbe · Call · Pichincha: Río Guaycuyacu, Ecuador · CC BY-SA 4.0

Photo: er-birds · CC BY 4.0

Vaux's Swift

Chaetura vauxi

Small17 gForest

This is a small swift, even compared to other Chaetura species, at 10.7 to 11.2 cm (4.2 to 4.4 in) long and weighing 18 g (0.63 oz). The northern populations are slightly larger at 11.5 cm (4.5 in), probably according to the Bergmann's Rule and/or migration requirements. It has a cigar-shaped body, crescentic wings and a short bluntly squared-off tail. The head, upperparts and wings are dusky black, and the underparts, rump and tail coverts are greyish brown. The throat is paler grey, becoming whitish in northern birds.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Adam Jackson · CC0

Photos and recordings are credited to their authors under the licence shown. Full profiles: Grey-rumped Swift and Vaux's Swift.