Purple Martin

Description

With an average length of 20 cm (7.9 in) and a wingspan of up to 38 cm (15 in), the purple martin is the largest amongst the 90 odd species in the family Hirundinidae. Measurement ranges: Length: 7.5–7.9 in (19–20 cm) Weight: 1.6–2.1 oz (45–60 g) Wingspan: 15.3–16.1 in (39–41 cm) Purple martins are sexually dimorphic. Adult males are entirely black with a 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. Adults have a slightly forked tail. Both male and female purple martins exhibit delayed plumage maturation, meaning it takes them two years before they acquire full adult plumage. 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 chests in a blotchy, random pattern as they molt to their adult plumage. Purple martins are quite vocal. They are known to chirp, chortle, rattle, and croak. Their various calls are described as "throaty and rich" and can be rendered as tchew-wew, pew pew, choo, cher, zweet, and zwrack. The males have a gurgling and guttural courtship song, a dawn song, and even a subsong used at the end of the breeding season. Recordings of purple martin song are sold to attract martins to newly established birdhouses. The species of this genus are very closely related, and some view the purple martin, gray-breasted martin, caribbean martin, and southern martin, as a superspecies.

Range & habitat

Purple martins' breeding range is throughout temperate North America. Their breeding habitat is open areas across eastern North America, and also some locations on the west coast from British Columbia to Mexico. 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. This makes their distribution patchy, as they are usually absent from areas where no nest sites are provided. Western birds often make use of natural cavities such as old woodpecker holes in trees or saguaro cacti. The birds migrate to the Amazon basin in winter. Their winter range extends into Ecuador but does not seem to ascend far up the Andean foothills. There are multiple records of long-distance vagrancy for this species. The first record of this species in Europe was in Dún Laoghaire, Leinster, Ireland in 1839 or 1840. The species was recorded at least six other times in the British Isles in the 1800s, and there are more recent records from Scotland in 2004 and the Azores in 2004 and 2011. There is also a record of two birds from Stanley, Falkland Islands (Las Malvinas) in 2004, and multiple records from Alaska, including records from Saint Paul Island in the Bering Sea and Fairbanks.

Adapted from Purple martin on Wikipedia, used under CC BY-SA 4.0.