If all goes as planned, 100 metro families will soon have scores of bats roosting just outside their doorsteps.

Saturday was the last day of Bat Week, an event held across the U.S. and beyond, and workshop participants at the Minnesota Valley National Wildlife Refuge Center in Bloomington assembled bat houses, lots of them. They were contributing to an international attempt to set a world record by making 5,000 homes for the furry flying creatures.

The contribution in Bloomington was never in doubt — supplies ran out halfway through the morning.

"This is creating exactly what [bats] want," said Jill Utrup, a U.S. Fish and Wildlife Service biologist.

Utrup said the wooden homes are better than the trees available for mothers to raise their pups.

"If a bat house is being used, you can look in and see their noses," she said.

The local event was part of an annual celebration whose organizers include bat conservation groups, the U.S. Forest Service and the U.S. Fish and Wildlife Service. Other Bat Week celebrations occurred Saturday throughout the U.S., Canada, Puerto Rico and Peru. Bat houses were also to be built in Ely and Silver Bay, according to batweek.org.

Conservation officials hoped the event — which also featured activities for kids and demonstrations of how biologists capture bats for studies — could help dispel the many myths surrounding the creatures. They're not blind, Minnesota doesn't have vampire bats, and they're not likely to swoop into your hair — it's mosquitoes they're after.

Bats are actually one of Minnesota's top insecticides, said Utrup, who sported a small black bat painted on her cheek. One pregnant female can eat up to, and sometimes beyond, its own body weight in insects, she said.

Saturday's event also aimed to educate residents about fungal diseases like white-nose syndrome, which has killed up to 6 million bats since its 2006 discovery in New York. Utrup said the disease has spread to Wisconsin and Canada. It hasn't been found in Minnesota yet. "We know it's just a matter of time before our bats are infected, too," she said.

Paula Adams, of Lake Elmo, brought her 8-year-old nephew, Wyatt, to build a house, and snagged one of the last available kits. They said the house took about 15 minutes to build, and all that's left is to add a fresh coat of black paint. Each summer, Adams said, she looks forward to watching bats come out at night outside her home.

Jason and Sherry Koons, of Woodbury, brought their daughter, Alexis, 10, in hopes of building a house, but arrived shortly after the last house was made. As Alexis worked on a bat coloring book, the Koonses reviewed instructions on how to install a bat house at home.

"We're just trying to be more environmentally friendly and keep the animals around as long as we can," Jason Koons said.

Stephen Montemayor • 952-746-3282