"East of the Rockies, martins now depend almost entirely on people for nest sites," says John Tautin, executive director of the Purple Martin Conservation Association in Erie, Pennsylvania.
adds that this is a good time for even more property owners to become landlords.
"Overall, the population of martins is stable," Tautin
says, "but it is starting to tip toward decline.
In particular, there's been a downturn along the northern edge of the species' breeding range.
"Minnesota has lost 75 to 80 percent of its martin population in the last 40 years," he
Numbers also have dropped in Canada and New England.