Research gives clues about how bats live

Bats can hear an insect walking. They eat up to 1,000 mosquitoes in an hour, live as long as 40 years and are the only mammal to truly fly.

And one bat species may have a bachelor pad in the San Juan Islands.

Rochelle Kelly, a University of Washington doctoral candidate, is studying bats to add to the limited information on their foraging habits, reliance on forests, and how sensitive they are to an isolated habitat.

Bats are difficult to study because they are creatures of the night.

“We don’t even know some of the basics of their biology,” Kelly said. “But they are incredibly diverse and have many amazing adaptations. They’re under-appreciated. But once I held my first bat, it was all over for me. And I’ve always been a fan of the underdog.”

On 217-acre Vendovi Island, Kelly trapped only two species on two outings, about 40 individuals, all male.

“That was surprising. I called it the bachelor pad,” Kelly said.

One hypothesis was that the more bats relied on unfragmented forests, the less likely they were to cross water.

“If that’s true, they probably don’t interbreed across islands,” she said.

Kelly spent last summer trapping bats on 13 islands, two to 10 nights on each. She’ll continue the research next year.

She uses mist nets to capture the bats, setting them in the best foraging areas such as near ponds, open fields next to woods and on trails with a natural overstory.

One surprise was on 564-acre Sucia Island, which had a really high diversity of species. Generally, the closer, larger islands had more species than the more distant, smaller islands. But Sucia is really isolated and in two nights Kelly captured five species.

“That’s a higher number on a few nights sampling relative to other survey efforts on larger islands. They might be more abundant on Sucia perhaps because there’s more (unfragmented) forest. It may not be an issue just of how much forest but how much is suitable habitat,” she said.

There are 15 species of bats in Washington, 10 in the San Juans.

Once captured, bats are placed in small bags and processed. The bag is also a handy fecal matter catcher, important for her study of guano back at the Burke Museum in Seattle.

Kelly sifts through fecal samples, extracts DNA and identifies insect parts to determine what different species like to eat. By analyzing the distribution and diets of bat species, she may be able to determine whether populations are regularly foraging and interbreeding or if certain species reside year-round.

Kelly does not set her nets on a full moon.

“Stories of bats at full moons are rampant. But they have reduced activity during a full moon. I don’t sample on a full moon. Maybe they’re less likely to fly in the open where they’re visible in the moonlight and more likely to hunt in darker habitats.”

Columnist Sharon Wootton can be reached at 360-468-3964 or www.songandword.com.