Notes: Small dumpy swallow w. iridescent blue back; brown
wings & notched tail; a rufous crown & nape; a whitish rump.
The underparts are dull white. Young birds are duller, browner, w. a paler
forehead & pale fringes to the back & wing feathers. Cf
the larger Tree Martin. Call a dry
buzzing "frrrtt," very different from twittering of Tree Martin. Unique "bottle"
nests constructed of mud & usually found under building eves, bridges,
culverts & cliffs.