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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Hanford bats welcome to stay, Energy Department says

Associated Press

RICHLAND – The U.S. Department of Energy says it’s OK for the largest known colony of bats in Eastern Washington to stay in its underground home at the Hanford Nuclear Reservation.

The 2,000 bats live in a concrete structure once used to hold Columbia River water – before it was used at a reactor. The structure was to be demolished as part of the Hanford cleanup, but that was before a contractor discovered the bats roost there from mid-March to mid-October.

The tiny bats – a species called Yuma myotis – seem to like their underground home, which hasn’t been used by anyone else in 30 years.

Washington Closure, the contractor handling cleanup in that area, launched a study to find out more about the bats after workers discovered them in 2006.

The Energy Department, which oversees Hanford cleanup, then began receiving letters urging it to let the bats remain after word of the creatures’ adopted home became public.

The U.S. Environmental Protection Agency, the regulator on the project, also agreed that the structure should be saved as a home for the bats. The agency concluded the structure had no chemical or radioactive contamination that would require it to be cleaned up, and the Energy Department agreed that it remained structurally sound.

“We didn’t want to disturb such great bat habitat,” said Craig Cameron, an EPA scientist.

The bats have developed a seemingly thriving colony and are reproducing, so the decision to let them remain is a good one, said Curt Leigh, manager of the Washington State Department of Fish and Wildlife major projects section.

The Energy Department said the contractor would put up a fence and signs to keep the bats from being disturbed. But because the site is in the secure area of Hanford across the Columbia River from the White Bluffs, only Hanford workers are nearby.

Each Yuma myotis weighs about 6 to 8 grams – less than two nickels – and has a body smaller than a mouse. But they look bigger in flight because of a wing span that stretches 6 to 8 inches. In a night they might eat their weight in small insects, such as the mosquitoes and midges that are plentiful along the nearby Columbia River.

Researchers believe the structure is used by a maternity colony with females each raising a single pup through the spring and summer.

In Washington, only one other known colony of bats, which lives under an Olympia pier, is believed to rival the size of the Hanford colony.