Northern Rough-winged Swallow
Stelgidopteryx serripennis
Adults are 13–15 cm (5.1–5.9 in) in length, brown above with white underparts, a small bill, and a forked tail. Their throat is white with a brownish-grey wash, and below the throat are white underparts. The adults have a wingspan of 27–30 cm (11–12 in) and a weight of 10–18 g (0.35–0.63 oz). The males' undertail coverts are longer and broader than those of the females. The males also have hooked barbs on the outer web of their outer primary wings. The barbs on the females are shorter and straighter than those of the males. Voice: The call of this swallow is described as a short, harsh zeep. It has also been described as a rough, low bzzt. It is often doubled. This call is similar to the call of the bank swallow.
ID text from Wikipedia, CC BY-SA 4.0
Southern Rough-winged Swallow
Stelgidopteryx ruficollis
The southern rough-winged swallow is about 13 cm (5.1 in) long and weighs 14 to 18 g (0.49 to 0.63 oz). The sexes have almost the same plumage. Adult males of the nominate subspecies S. r. ruficollis have a mostly dark gray-brown head with a cinnamon throat. Their upperparts are mostly dark gray-brown with a slightly paler rump. Their tail is square; it and their wings are blackish brown. Their wings' outer primaries have stiff recurved barbs on their outer webs that give the bird its English name. Females lack these barbs. Voice: The southern rough-winged swallow's most common vocalization has variously been described as "an upslurred suree", "a musical, rising zwee", and "a distinctive rough, upslurred djreeet". It also makes twitters and other buzzy vocalizations.
ID text from Wikipedia, CC BY-SA 4.0
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