The number of migrating golden eagles (Aquila chrysaetos) through Montana’s Bridger Mountains, the top fall golden eagle migration route in the Lower 48, has dropped 35 to 40 percent over the past two decades, mirroring similar declines at migrating raptor count sites elsewhere in the West and raising concerns for Montana Audubon, which conducts the surveys. Steve Hoffman, executive director of Montana Audubon, says the declines in southwest Montana are being documented in migrating golden eagles, which could indicate habitat loss in wintering grounds in the United States or problems in breeding areas in Canada and Alaska. The decline in numbers of golden eagles has been documented in annual raptor counts conducted at Bridger Bowl Ski Area near Bozeman since 1992. Each year, from Sept. 1 to late October or early November, two official observers count raptors from a helicopter-landing platform at an elevation of 8,600 feet. In the 2013 survey, which concluded earlier this month, the trend of declining golden eagles continued with 1,131 golden eagles counted compared to 1,272 in 2012. In 1992, the first full year of survey results, 1,579 golden eagles were recorded. In 1999, the last year counters recorded a high number of eagles, 1,870 golden eagles were spotted. "Our data in the Bridgers has determined it is a problem,” Hoffman said. Since the late 1990s, the number of birds counted has declined 35 to 40 percent, the survey results show.
Great Falls Tribune, November 13, 2013