Bob Wisecarver’s bat houses are a bit like snowflakes: No two are exactly alike. Each is designed to meet specific needs and utilize the mostly salvaged materials he converts to abodes for bats throughout northern California. His most unusual creation is a unique and extremely successful “bat cave” that provides a home for some 9,500 bats in the spillway of the Pardee Dam, northeast of Stockton.
In 1995, the East Bay Municipal Utility District sealed several openings in a spillway during renovations of the dam, which displaced a small colony of Mexican free-tailed bats that had been living inside the structure. The district turned to Wisecarver, a longtime BCI member, for help in providing a new home for the bats.
He was a logical choice. The 86-year-old, retired Walnut Creek resident, known as “Bat House Bob,” has been a remarkably active bat-house builder and advocate since encountering a copy of BATS magazine in 1993. He started out with plans from BCI’s Bat House Builder’s Handbook, then added special touches based on his own observations and insight. His distinctive – and usually successful – bat houses were already scattered throughout the area when the utility district came calling.
Wisecarver visited the dam with a district engineer and decided to turn one of the cubicles, each 10 feet high, wide and long, into a bat roost – “an instant bat cave.”
He and his team assembled five modules – 5-foot-long rectangular boxes divided by parallel panels to form roosting chambers. The modules are similar to those often used now as bat roosts under bridges.
“They were all 10 inches high because that’s what I had in the way of fence boards, but they were all built differently,” Wisecarver said. “All the houses had different spacing, as we didn’t know what kind of bats we would get and what they liked best.” This was in the very early days of BCI’s pioneering North American Bat House Research Project, which began in 1992, and reliable information was hard to come by.
The wide-open front of the cubicle was closed off by a plywood wall with a door that included three rectangular openings for the bats.
The Pardee bat cave got off to a slow start, but Wisecarver kept improving the concept and fine-tuning the roosting modules. Among many changes, he barred the entrance holes to keep owls away, added vents to cool the roost and made almost all the roosting chambers three-quarters of an inch wide.
The bat colony in the dam keeps growing. “I have a deep sense of pride in my gut for this whole thing,” Wisecarver said. “But as the saying goes: All good things must end.” He says this likely will be his last year working at the dam. So now he’s looking for someone to take the baton and continue the program he began so long ago.
But if you ever wonder whether one person can make a difference, look no further than Bat House Bob Wisecarver.
BCI Members can read the whole story of Bob Wisecarver’s conservation work at Pardee Dam and elsewhere in the Fall 2007 issue of BATS magazine.