yolo underbelly

I'm finally getting around to posting some pictures from the NASBR conference. One evening a few of us drove over to the Yolo Causeway, a part of I80 just west of Sacramento, California. This is essentially a long bridge over some flooded fields and other wildlife habitat. A colony of some 250,000 Mexican freetail bats (Tadarida brasilensis) lives under the bridge during part of the year. The bats live in tiny crevices that run along part of the underside of the bridge. You can see the urine stain evidence in this photo. We could smell them from a distance, a very musky smell that soon became overwhelming. Up close we could see their guano everywhere and hear them chirping. At sunset they dropped out of the crevices as if from an upside-down toaster, and flew away.