About Petrochelidon nigricans (Vieillot, 1817)
Tree martin (Petrochelidon nigricans (Vieillot, 1817)) averages 13 cm (5.1 in) in length, and has a shallowly forked tail. Adult tree martins have an iridescent blue back and crown, brown wings and tail, a rufous forehead, a whitish rump, and white underparts. The sexes have similar plumage. Young birds are duller and browner than adults, with a paler forehead and pale fringes on the back and wing feathers. This vocal swallow produces a call described as tsweet, and its song is a high-pitched twitter. This species can be told apart from other Australian swallows by its tail shape and pale rump. The most similar species, the fairy martin, has a rufous head and nape.
