Bring Back the Martins

When we bought our house, the previous owner left three purple martin apartments that she said were occupied by as many as 44 pairs of martins. But they stopped coming about 3 years before we bought the property because she was unable to maintain the houses. Since then, I've been cleaning the houses every year and keeping other birds out, but haven't attracted any martins. Am I doing something wrong?

—Gerry Waters, Welland, Ontario

George: Purple martins are birds of tradition. Once they establish a colony in a birdhouse, they're likely to return to the house year after year. If that tradition is broken, it's difficult, but not impossible, to reestablish it. There's a good chance the martins that once nested around your area suffered a decline in their population, perhaps due to a late frost or a die-off in their tropical wintering grounds. Your patience should pay off, however. When the local population recovers, it should expand into new nesting sites during coming springs. The best way to get them to return is to continue what you're already doing—keeping the apartments ready for occupancy. If there's good production of purple martins in your area, the overflow may eventually reclaim your houses.