VINALHAVEN — U.S. Fish and Wildlife Service biologists are questioning a study that concluded that three wind turbines on Maine’s Vinalhaven Island kill fewer than 10 birds a year.

Ornithologist Richard Podolsky conducted a 28-month study to determine the turbines’ effects on local eagles and ospreys, as required by the island town. Podolsky told the Bangor Daily News that no dead eagles or ospreys were turned up. He estimated that each turbine results in only two or three bird deaths a year.

In response, the Fish and Wildlife Service wrote a letter saying the turbines pose a “substantial risk” to eagle populations. The letter says dead bird searchers should have searched more often and in a wider area.

Podolsky says the study exceeded the town’s requirements of at least monthly surveys.