Sub-category: Swallows & Martins
The largest North American swallow. These aerial acrobats have speed and agility in flight, and when approaching their housing, will dive from the sky at great speeds with their wings tucked. The average length from bill to tail is 7.9 inches. Adults have a slightly forked tail. Adult males are entirely black with glossy steel blue sheen, the only swallow in North America with such coloration. 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.
Martins make their nests in cavities, either natural or artificial. In many places, humans put up real or artificial hollow gourds, or houses for martins, especially in the east, where Purple Martins are almost entirely dependent on such structures. As a result, this subspecies typically breeds in colonies located in proximity to people, even within cities and towns.