Unalaska, AK – The Ornithological Council has released a report on the rodent-eradication project on Rat Island, focusing on the number of bird deaths the occurred as a result.

The goal of the $3 million eradication project was to exterminate the invasive rat population, which had a negative impact on the seabirds that have traditionally migrated to the island. In the fall of 2008, the U.S. Fish and Wildlife Service, with assistance from Nature Conservancy and Island Conservation, dropped rat poison onto the island via helicopter. The project worked. By 2009, the island was rat free.

But in the process, more gulls and eagles were killed than expected. The report by the Ornithological Council, which was commissioned by Nature Conservancy, determined that 46 bald eagles died, with 75% of the carcasses testing positive for the poison. Only 22 eagles were believed to have lived on the island - the abundant food supply created by the rats may have attracted eagles from other islands. Over 300 Glacous-winged gulls also died, along with 54 other birds representing 25 different species.

Poppy Benson, the public programs supervisor with the Alaska Maritime Refuge, spoke about the project at the Unalaska Library last week. She explained why the bird mortality rate was higher than expected, given that the 85% of the rats were expected to die underground.

"They're wandering around the surface sick, and because the two bait applications were put on so close together the little rats just stuffed themselves with bait and they were really hot," said Benson. "So, if a gull or eagle got this staggering rat, the rat had a lot more poison in its body than we expected it would have."

The report lays out a number of reasons as to why the bird mortality rate was higher than expected, and it focuses especially on monitoring. But unfortunately, Benson said, it wasn't possible to linger on the island due to weather conditions.

"We're the Fish and Wildlife Service - we don't want to be killing birds," Benson added.

However, these mortalities have not had a critical impact on Rat Island's bird population. Since the eradication of the rats, Aleutian cackling geese, ptarmigan, peregrine falcons and black oystercatchers have all started to nest on the island once again - in addition to eagles and gulls.