EAU CLAIRE, Wis. (AP) -- Purple martins will begin returning to Wisconsin to nest in coming days, but some bird enthusiasts say their numbers are on the decline.
Purple martins are the largest of the swallow family in Wisconsin. They depend on man-made birdhouses for lodging.
Steve Betchkal of the Gaylord Nelson chapter of the Audubon Society says his group is starting a mapping project to track the birds in northwestern Wisconsin.
Betchkal tells the Eau Claire Leader-Telegram reports (http://bit.ly/1ll9vCT ) that last year he didn't hear or see a purple martin anywhere in the state.
Housing may not be the only issue. The birds face competition from house sparrows and starlings. In addition, they eat insects so face starvation if cold weather impacts the bug population.
Information from: Leader-Telegram, http://www.leadertelegram.com/