Spring 2000 Table of Contents

Ups and downs of Purple martins and people

One native part-time resident of Washington that has an up and down history of close relationships with humans is the purple martin (Progne subis).

This largest member of the swallow family migrates to central Brazil where it winters in flocks of up to 100,000, often using big city night roosting spots to avoid predators. They return to their same cavity-nesting sites on our coast by the first of April each year.

Martins were first lured to man-made nest sites by Native Americans who hung hollowed-out gourds in their villages. They were desirable for driving crows away from crops and vultures from meats and hides, as well as providing melodious song, aerial acrobatics, and insect consumption.

Over thousands of generations, purple martins became adapted to nesting in man-made gourds, likely because they gained some security from predators near humans. Gourds provided more space than natural cavities, which enabled martins to lay more eggs and raise more young. The clustering of gourds also allowed more martins to nest together (as compared to solitary woodpecker holes) which increased breeding attempts and security to the colony.

When European colonists arrived in America, they too hung natural gourds, ceramic gourds, and wooden houses for martins to nest. By the 20th century, the entire eastern race of purple martins nested only in man-made houses. In the Pacific Northwest and Southwest, martins continue to nest in both natural and man-made cavities.

From 1900 to 1950, as the human population increased in Washington, martins became locally common from Bellingham to Vancouver and the Columbia River, including one flock in Seattle that exceeded 12,500 individuals. This population increase was short-lived, however. In the late 1940’s the European starling and House sparrow were introduced to Washington and their aggressive competition for nest sites drove purple martins into decline.

Today, volunteers across Western Washington are working to bring back purple martins. More than 35 colonies have been established by local Audubon chapters and bird enthusiasts. Establishment of a colony includes mounting purple martin nest boxes or gourds and annually monitoring and maintaining them. Key to success is using boxes or gourds with proper specifications, providing several boxes at the same location (clustering), and keeping them free of nest competitors and predators. The Purple Martin Conservation Association was created to help people interested in establishing a purple martin colony. This non-profit group can be reached by phone (814-734-4420), email pmca@edinboro.edu, or website http://www.purplemartin.org.

WDFW is working cooperatively with British Columbia, Oregon, and California to manage purple martins along the west coast. Nest boxes are annually checked, recording the number of eggs and chicks. Hundreds of purple martin chicks are also leg banded each year at the largest colonies with each state/province using a different leg band color. The leg bands help biologists understand site loyalty, migration, colonization, and chick survival. Blood samples were taken in 1999 for a genetics study that will attempt to learn whether purple martins using man-made nest boxes along the west coast evolved from the same ancestors. If so, the size of the purple martin population could be limited by available nest boxes in a ‘bottle neck’ fashion.

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