The Case of the Missing Martins

from Wildlife Promise

 

Purple Martin by Richard Winegar

A purple martin delivers a dragonfly to its chicks in a Florida backyard. Photo by Richard Winegar.

A few weeks ago, I headed down Interstate 95 from my home in Washington, D.C., to attend a quirky festival, “Gone to the Birds,” held each August in Richmond, Virginia. The festival celebrates purple martins, and it is timed to coincide with peak numbers of these dark, long-winged birds swooping down to roost overnight in a dozen Bradford pear trees in the city’s Shockoe Bottom neighborhood. For at least the past decade—and possibly longer, according to some records—tens of thousands of purple martins have roosted nightly here in July and August before flying south to spend the winter in Brazil. But this year, for the first time in the festival’s history, the event took place without its guests of honor. Indeed, no gatherings of purple martins were observed at their traditional Richmond roost site all summer long.

At first, local martin fans assumed the birds were just running late. “This year, we had an exceptionally cold and wet spring,” says festival organizer Adolph White, who maintains several purple martin nest boxes in the city’s Bryan Park. “That meant fewer insects, which the birds need to feed themselves and their young.” Hoping the birds were just getting a late start to nesting—and therefore post-breeding roosting and migration—White and other organizers initially postponed the festival for three weeks.

Cold, Wet Spring

Biologists confirm that purple martins, North America’s largest swallows, are sensitive to unusual weather. In an article, “Painting Your Yard Purple,” in the current issue of National Wildlife, swallow expert and University of Tulsa professor Charles Brown says that this year “the Great Plains endured one of the coldest springs on record, and we may be experiencing martin declines as a result.” The reason, he told writer Doreen Cubie, is that martins are among the earliest migratory birds to return north from the Tropics. “Martins eat only insects,” Brown added, and the appearance of insects can be delayed by cold weather in spring.

At Richmond’s martin-less martin festival, where a few dozen disappointed attendees browsed bird-themed t-shirts, jewelry and tote bags (compared to more than 1,000 participants last year), explanations for the birds’ disappearance ran the gamut. The most popular was a conspiracy theory: that city officials, eager to construct a new baseball stadium where the pear trees now stand, had secretly installed devices that emit ultrasonic sounds to scare birds away.

Moveable Martin Roosts

Purple Martins by Nancy McCarthy

Nancy McCarthy has been a landlord to this purple martin colony since 2004. Photo by Nancy McCarthy.

When I got home, I contacted John Tautin, executive director of the Purple Martin Conservation Association (PMCA), to see what he thought. Tautin told me that the disappearance of post-breeding martin roosts is not that uncommon. “In most cases, and probably in Richmond’s, the roosts don’t actually disappear, but move to a new location,” he said. “Some years ago, a big one in Alabama moved, and this year a modestly-sized one in Minnesota moved. Disturbance may cause some roosts to move, but most seem to move for reasons unknown to us.”

Tautin suggests that next summer martin watchers in Richmond monitor Doppler radar in the region to see if they can find their missing roost. (PMCA colleagues officially confirmed the Richmond roost’s existence using radar in 2004.) Whether the huge annual gathering of birds has disappeared or merely relocated, purple martins need all the help they can get, he adds. “Overall, the population of martins is stable, but is starting to tip toward decline”—particularly at the northern edge of the species’ breeding range in Canada, Michigan and New England.

One possible reason for those declines: “East of the Rockies, martins now depend almost entirely on people for nest sites,” Tautin says. He adds that fewer homeowners install purple martin nest boxes these days than they once did.

Certify Your Wildlife GardenHelp purple martins! Find out more about purple martin nest boxes and how to properly place and maintain them, then consider turning your property into a Certified Wildlife Habitat® site.