Bats of Cosumnes River Preserve

Sunday, May 1, 2011. The Western Section of the Wildlife Society Sacramento-Shasta Chapter had its annual members-only barbecue at the Cosumnes River Preserve. The preserve is just south of Elk Grove and north of Stockton, California, with easy access off of Interstate 5. I usually go there for the birding--the paths through wetlands with a rich diversity of waterfowl and wading birds--and during the time of year when sandhill cranes migrate through and can be seen in large numbers, flying overhead, or settling into the adjacent rice fields. But on this day, I wasn't there for birding or for viewing sandhill cranes. This time I came for the bats. Well, and to be a good Wildlife Society Board member and help with the picnic. Before food or bats, we piled into trucks and vans and followed employees of Westervelt Ecological Services, a company that restores wildlife habitat, to one of their properties near the preserve. This land had originally been privately owned and used for agriculture, but being surrounded by the Cosumnes and Mokulumne Rivers, creeks, and sloughs made it prone to too much flooding, so the land was sold as a mitigation bank. Now the goal is to restore the riparian forest that was once there, and that would support the diversity of wildlife that depended on that forest. A huge but laudable undertaking.
Now (before restoration):

After restoration, it will hopefully look like this:

Now the bats. Just slightly south from the entrance to the preserve, on Franklin Blvd., there is a long bridge where the road crosses the Mokolumne. Mexican free-taied bats roost under the bridge, and just at a precise moment between dusk and dark, they emerge in the thousands, in a steady stream of organized flight, to set out into the night sky and begin foraging. The hawks sit in the trees and wait. If one is lucky, it will dive into the flurry of circling bats and pick one off in flight. We were at the right time and place to witness such a phenomenon. It's like standing in a scene from BBC's Planet Earth.

Chris and I also have seen bats emerge from under the causeway of Interstate 80 just west of Sacramento. The Yolo Wildlife Area does bat tours regularly. It's worth seeing. Especially since bats get a bad rap and they are among the cutest animals imaginable. Some of the common myths about bats are ludicrous. They eat fruit and insects, and the one species (vampire bats) that consumes blood (usually from cows) seals the wound with an antiseptic and the cow doesn't feel a thing. Bats are now facing a decline because of a fungus-caused disease (White-nosed syndrome) that is spreading throughout the country. For this and other reasons, many species of bats need protection. Any of us can learn about these adorable mammals and help them in many ways.