UKBirds

Purple Martin

Progne subis

The Purple Martin (Progne subis) is 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.

Purple Martins are a kind of swallow, of the genus Progne. Like other members of this genus, they are larger than 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, 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.

This species was first described by Linnaeus in his Systema naturae in 1758 as Hirundo subis. The species of this genus are very closely related, and some view the Purple Martin, Gray-breasted Martin, Snowy-bellied Martin, and Southern Martin, as a superspecies.

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 Purple Martin migrates to the Amazon basin in winter. Its winter range extends into Ecuador but does not seem to ascend far up the Andean foothills.

The first record of this species in Europe was a single bird on Lewis, Scotland on 5-6 September 2004, and the second was on the Azores on 6 September 2004.

Purple Martins suffered a severe population crash in the 20th Century widely linked to the release and spread of European Starlings in North America. Starlings and House Sparrows compete with martins for nest cavities. Where Purple Martins once gathered by the thousands, by the 1980s they had all but disappeared.

The population of eastern Purple Martins (nominate form P. s. subis) is dependent on artificial martin houses of wood or aluminum and fake plastic gourds, supplied by individuals and organizations fond of the bird. This tradition was in place even before the population crash; Native Americans are said to have hollowed out gourds and erected them for this purpose. The situation requires ongoing maintenance, as European Starlings and House Sparrows compete with martins as cavity-nesters, and will fight with martins over nest sites. Starlings have even been known to kill Purple Martins, especially nestling young, and Purple Martins have been known to evict House Sparrows from their nests. Thus, unmonitored Purple Martin houses are often overtaken by more aggressive, non-native species. Purple Martin proponents are motivated by the concern that the Purple Martin would likely vanish from eastern North America were it not for this assistance.