An encounter with Townsend's Big-Eared Bats
It was shortly after eight on a summer evening when we climbed the hill to the emergence site. We communicated in whispers and hand signals. The bat we hoped to see was notorious for being easily spooked. As quietly as possible we figured out the best lines of sight and settled down to wait. We didn't have to wait long. Within minutes we saw a pale form zip in front of us. Then another! And another! More and more came up and out the vent in the hill. The bat detectors were clicking away, lights flashing. They were here! And in large numbers!
This scenario probably doesn't sound much different from any observation of a bat emergence. But there were several things that made this instance very special. For one thing, these were Townsend's Big-eared Bats, one of Washington State's rarest. Secondly, they were emerging from a roost where the previous year bats had been killed by human 'adventurers' and only a single bat had dared to hibernate through the winter. And thirdly, this predominantly cave-dwelling bat wasn't coming from a cave -- it was flying out of an old, abandoned World War II bunker! A couple years before, reports of bats living there had filtered into the Fish and Wildlife Department. The first time we checked it out, we found no bats. What we did find was evidence of activities that would have sent the easily disturbed Townsend's bats to roost elsewhere. There were signs that people had built fires inside. Numerous bottles and beer cans indicated less-than-quiet human use. Tire tracks from motorcycles ran through the interior of the bunker. The site had obviously been used for paint-ball battles and, judging by the spent shells, a target range.
The situation was brought to the attention of the Cave Habitat Management Working Group, an interagency group formed by Eric Larsen of the WDFW. This group knew the bunker might again be good habitat for the bats if it was gated. 'Gating' is the construction of steel bars across openings that allow bats to fly in and out, but prevent human access. But gating is difficult, expensive and sometimes rendered ineffective. (There have been many instances where the displaced human users of a gated cave went to great trouble to destroy the heavy steel bars that prevented their use.) The fact that the bunker had been used as a hibernacula by at least one Townsend's bat the previous winter moved the group in favor of the gating. With funds donated by Bat Conservation International, labor from a nearby prison, and the expertise of members of the Northwest Chapter of the American Cave Conservation Association, the WDFW and the Department of Natural Resources worked together to get the gates up.
That night last summer, we would have been happy to see five or six bats emerge from the barred doorways, indicating that they were beginning to use the site again. To see more than a hundred was beyond our wildest dreams. It means that this population was able to recover quickly once they were protected from disturbance. It also holds out the hope that other old bunkers, which dot the West Coast of the United States, may be providing alternative housing for this species. But perhaps most important is that it shows what a difference concerned people can make when they work together to protect our native bats.