The great American Martin

Every year, up to 800,000 martins migrate to their breeding grounds in North America from Brazil. They fan out across the entire United States and into Canada in search of birdhouses on farms, fields, lakes and rivers. Meanwhile, “martin landlords,” welcome their arrival with clean, spacious homes to raise their new broods.

In South Carolina, Purple Martins arrive in February and stay through August. Males are recognized by their glossy, midnight blue feathers, while the female is duller with lighter underwings. Early arriving birds are sometimes called “scouts,” but these are actually older birds getting a head start on last year’s housing. On Hilton Head, the Sea Pines community garden has erected eight martin “condos,” complete with wraparound porches. Provided homes remain clean and safe from predators, martins return every year to the same nesting site.

Purple Martins are called “aerial insectivores.” They forage on flying insects “in mid-air, on the wing. Contrary to popular myth, mosquitoes account for only two percent of the martin diet, not 2,000 a day. The oft-claimed quote stems from an ad campaign for martin houses that stated, “Purple Martins CAN eat 2,000 mosquitoes a day.” Perhaps they can, but they don’t. Martins forage high in the air on large dragonflies, bees, beetles and wasps. Mosquitoes hang close to the ground so their flight paths seldom intersect.

Purple Martins have cohabitated with humans ever since Cherokee tribes enticed them to their villages with hollowed gourds. American settlers followed suit, tempting the sociable birds with impressive gourd racks and apartment-style homes. It was a win-win deal — safe housing in exchange for pest control. In 1831, John James Audubon wrote in his travels across America, “Almost every country tavern has a martin box…the more handsome the box, the better does the inn generally prove to be.”

Though impossible to determine, educated estimates suggest the Purple Martin population numbered 70 million in the mid-1800s. Audubon described “prodigious numbers” of martins around the country and wrote about a flock in New Orleans that was “a mile and a half in length, by a quarter of a mile in breadth.” But martins lost out in the nineteenth century when vast forests were cleared in the eastern U.S.

About the same time, invasive starlings and house sparrows from Europe were released into America, and they hijacked the tree cavities where martins once nested. Today, Purple Martins east of the Rockies are almost totally dependent on people to provide nesting sites. They are on the Watch List; their numbers have declined 25 percent since 1966, primarily due to habitat loss and overuse of pesticides.

The current worldwide population of Purple Martins is 9.3 million. An estimated 900,00 landlords volunteer in the U.S. and Canada, but 95 percent are fifty years and older. Groups like the Purple Martin Conservation Association and the National Wildlife Federation work to promote and provide opportunities for younger generations to become landlords, citizen scientists, and volunteers to reverse the martin’s decline.

As you read this article, Purple Martins are preparing to fly back to South America for the winter. But first they gather in enormous colonies called “roosts,” where hundreds of thousands of birds meet to rest, refuel and socialize before leaving on their 3,000 mile journey back to Brazil.

The largest Purple Martin roost in the country is three hours away in Columbia, South Carolina. Since the 1980s, up to a million martins have gathered on Lake Murray’s Bomb Island, a former military training site in WWII. In July and August, skies appear as living clouds of darkened birds swirling, twirling, dipping and diving over the island.

More an avian force than a flock of birds, boaters gather round all summer, mesmerized by the natural phenomenon. The roost is Lake Murray’s must-go summertime show; tours and boat rentals can be made online for a reasonable fee.

Learn more about attracting Purple Martins at www.purplemartin.org or National Wildlife Federation www.nwf.org

Rosemary Staples is a member of Hilton Head Audubon, long time Lowcountry resident, writer, speaker, storyteller and Master Naturalist.