West Nile virus holds no fear for Bob Blank, thanks to dozens of warm-weather guests at his Lawrence home.

Come spring every year, about 100 brown bats show up at Blank’s house. They stay for the summer, leaving only when the weather turns cold.

“I hardly know they are there,” Blank said of the bats that pack themselves into two bat houses outside of his Owens Lane house.

Once the mosquito-borne West Nile virus reached Kansas, Blank and his wife, Elaine, had no qualms about sitting out at night.

“There are no mosquitoes bothering us,” said Blank, 74. “The bats eat them all. They eat thousands upon thousands of mosquitoes.”

Blank said that was why he decided about six years ago to buy his first bat house. But it took about two years before the first few bats took up residence.

“More of them started coming in, and a couple of years ago I decided to get another” bat house, Blank said.

Dozens of brown bats huddle together inside a bat house outside Bob Blank's home in central Lawrence. More than 50 bats can crowd into each house to sleep during the day after a night of rummaging for food, mostly mosquitoes.

The bat houses are wooden boxes about a foot long and 10 inches wide with open bottoms where the bats enter. Inside the houses are wooden louvers. The bats use their claws to dig into the louvers and hang upside down, sleeping during the day.

Each bat is only a few inches long, and they pack themselves along the louvers in rows, side-by-side. Each of the bat houses could hold about 100 bats, Blank estimated. But only about 50 generally appear to be in each house.

Below the bat houses Blank puts pans to catch the guano, which is considered excellent plant fertilizer. Blank uses it on his flower beds.

“There are no flies and no smell,” Blank said as he stood by the pans. “It’s not like a barnyard.”

Blank said he didn’t worry about being bitten by the bats, sometimes known to carry rabies. Only once has he had one in the house; he used gloves, a T-shirt and a butterfly net to remove it.

There’s no need to fear bats, said Bruce Chladny, horticultural specialist with Douglas County’s K-State Research and Extension office.

“As with any wildlife, as long as people practice common sense and caution, they’re going to be safe,” Chladny said.

Bat bites often occur when someone tries to handle a bat found on the ground, he said. And bats are not known to attack people.

“That’s all Hollywood,” Chladny said.

Bat houses can typically be purchased at stores that sell birdhouses. Plans for building a bat house are available at Chladny’s office.