Photo Credit: Bill Horn
SCIENTIFIC NAME: Progne subis
OTHER NAMES: Gourd martin, black martin.
DESCRIPTION: Purple martins are a small, robin-sized bird about seven to eight inches high. They are members of the swallow family, a group of insect eating birds that catch their prey almost exclusively in flight. They are Alabama’s largest swallow and have long, pointed “swept-back” wings and a slightly forked tail. Adult males are a dark, glossy, steel-blue – which gives the species its common name. Females and immature males are duller on the back and pale gray on the underside.
DISTRIBUTION: Found in southeastern and central Canada, south throughout most of the continental United States, along the Pacific Coast, and south into Mexico. It is found statewide in Alabama during the spring and summer and is our state’s most widespread swallow.
HABITAT: The purple martin is a bird of open woodlands, agricultural lands and residential areas. They can be found in almost any open area, but local populations are influenced by the presence and abundance of suitable nesting cavities. They may often be seen perched in large groups on wires and rooftops.
LIFE HISTORY AND ECOLOGY: The purple martin is a migratory bird and their annual arrival from the southern hemisphere heralds the beginning of spring. Highly social and gregarious birds, they tolerate and can even thrive in close association with humans. Southern Native Americans and early settlers established a custom of hanging hollow gourds in trees near their gardens to establish colonies of these birds. Contemporary martin lovers may erect large artificial houses, as well as “hollowed out” gourds to establish martin colonies. Natural cavities such as hollow trees and holes made by woodpeckers are used when available, though they usually do not form the large colony size seen in artificial nesting structures.
Purple martins are almost entirely insectivorous, and are adept flyers feeding almost entirely on-the-wing. They eat flying insects of all sorts including eating bees, wasps, beetles, butterflies, dragonflies and mosquitoes. Occasionally, ground dwelling ants, spiders, and weevils are also taken. Their call is a flowing warble, and also a tee-tee-tee.
Nesting occurs in the spring when a mass of grass and other plant material is placed in a nesting cavity. Females lay and incubate 4-5 white eggs, but both sexes share in caring for young. Individual birds have a tendency to return to the same nesting structure year after year.
Large groups of pre-migratory roosts form during August and September and sometimes these roosts can number several hundred thousand birds. One particularly large roost of over 300,000 birds has been noted on several small islands below Wheeler Dam on the Tennessee River in Lawrence County, Alabama. This creates an impressive sight when thousands of birds fly into these small islands each evening in late summer between sunset and dusk. In the spring, it is one of the earliest birds to return from migration.
Purple martins are loved and enjoyed by a great many people and several groups exist to promote conservation and management of the species. In many areas, local hobbyists form purple martin clubs. National groups such as the Purple Martin Society (www.purplemartins.com) and the Purple Martin Conservation Association (www.purplemartin.org) exist to promote the species. Over one million North Americans put up housing for purple martins.
PREPARED BY: M. Keith Hudson, Wildlife Biologist, Alabama Wildlife and Fisheries.
See the article about the purple martin migration from Outdoor Alabama magazine.