The Purple Martins are larger than most other swallows. The average length from bill to tail is 20 cm (7.9 in). Adults have a slightly forked tail. Adult males are entirely black with glossy steel blue sheen. Adult females are dark on top with some steel blue sheen, and lighter underparts. Subadult females look similar to adult females minus the steel blue sheen and browner on the back. Subadult males look very much like females, but solid black feathers emerge on their chest in a blotchy, random pattern as they molt to their adult plumage.
Habitat and Distribution
Purple Martins' breeding habitat is open areas across eastern North America, and also some locations on the west coast from British Columbia to Mexico. In many places, humans put up real or artificial hollow gourds, or houses for these birds.Western birds often make use of natural cavities such as old woodpecker holes in trees. The Purple Martin migrates to the Amazon basin in winter. Its winter range extends into Ecuador but does not reach the Andean foothills.
Purple Martins are aerial insectivores, meaning that they catch insects from the air. They are agile hunters , usually flying relatively high.
The nest is made inside the cavity of artificial structures and retains a flat appearance. It consists of three levels: the foundation(made of twigs, mud, pebbles); second level(grasses, fine small twigs) and the third level(made of usually lined with fresh green leaves where eggs are laid). Three to six eggs are laid and the female incubates them.
Calls and Songs
The various calls are said to be throaty and rich and can be rendered as tchew-wew, pew pew, choo, cher, zweet and zwrack.