Purple Martins, Colony Nesters
Colonies, Breeding, Range, Migration and Interesting Facts
Jun 12, 2008
Swallows are familiar birds all over the world: a sign of spring like the American Robin. Purple Martins (Progne subis) are well known in eastern North America because they nest in man-made colonies, and in southern North America during fall migration because they roost together in impressive numbers. Their breeding range extends as far north as the Canadian Maritime Provinces, and into the central Canadian prairies. In most of the western half of the continent, the bird is less common and less conspicuous because there it uses holes in trees and cacti for nesting.
What do Purple Martins Look Like?
Progne subis adults are about the size of a European Starling and may look similar in flight. Males are uniformly shiny blue-black with a short forked tail and pointed wings. Females look similar but have a light grey breast, neck, and forehead. Western females tend to have lighter breasts.
Purple Martin Colonies
Colonies are located near water where the birds can find abundant food—like swifts, Purple Martins feed on insects caught in the air. Breeding males arrive first, selecting and defending nesting sites, and waiting for females to arrive a few weeks later.
Once birds have paired off (males may pair with more than one female) the birds spend nights together in the nest hole before nest building. Females lay three to eight eggs. Young are fed by both parents and fledge after about a month.
Purple Martin Migration
Flocks of thousands of birds migrate to roosts in South America, predominantly the Amazon region, beginning in late summer. Birds that have not succeeded in breeding gather first at roosts near rivers and streams. They are soon followed by birds that nested or fledged early, and finally by those from late or second nests. They reappear in the south of their breeding range by February each year.
Interesting Facts About Purple Martins
Here are some curious things about Progne subis:
- Legend has it that this species feeds abundantly on mosquitoes; however, these unpopular insects tend to fly near the ground in the evening hours, while Purple Martins hunt high in the air during the day.
- Purple martins that nest in various locations in North America share the same South American roost in winter. This was proven when birds from roosts in Brazil were tagged with a fluorescent dye. Using ultraviolet light, researchers in the eastern US identified the tagged birds in various nesting areas the following summer.
- During nest building males perform “dawn-song” in the early morning, flying above the colony. This is thought to attract other Purple Martins to the colony.
- During laying, green leaves are added to the nest (mostly by the male), possibly to raise humidity or to deter pests.
- At a fall migration roost on a bridge in New Orleans, so many birds were being killed in traffic that a citizens group successfully spearheaded the installation of protective fencing.
- Because they migrate by day, roost where food is plentiful, and hunt while in flight, migrating Purple Martins feed as they go; therefore, they don’t need to store large amounts of fat like hummingbirds and many other migrating birds.
Watch Purple Martins on Bird Cinema
Common Sources:
Atlas of Bird Migration. Elphick, Jonathan ed. Buffalo: Firefly Books, 2007.
Birds Of North America Kaufman, Kenn. New York: Houghton Mifflin; 2000
Firefly Encyclopedia of Birds. Perrins, Christopher ed. Buffalo: Firefly Books, 2003
Purple Martin and Killdeer Nest-Cam 2008. New York Wild.
Smithsonian Field Guide to the Birds of North America Floyd, Ted. New York: HarperCollins; 2008.
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