Good news: Tucson's dead bats aren't a sign of the apocalypse. Bad news: someone thought it would be fun to kill a bunch of bats.
From the Game and Fish Department:
The Arizona Game and Fish Department (AGFD) has determined that the probable cause of death for approximately 80 bats found dead or dying beneath the Speedway Bridge over the Pantano Wash the week of Dec. 27 died from ballistic trauma caused by a BB gun.
Eleven bats examined at a department lab in Phoenix bore signs of physical trauma consistent with being shot with a 4 millimeter BB gun, and three such BBs were recovered from their bodies. A fourth BB and similar trauma was found during necropsies of four bats performed by a U.S. Geological Survey lab in Madison, WI, which ruled out White Noise Syndrome as the cause of death. Rabies was previously ruled out as the cause of death by the Arizona Department of Health Services in Phoenix.
The remaining bats removed from the scene by the Pima Animal Care Center also exhibited physical trauma consistent with the finding. Trauma apparent in the necropsies ranged from mild to severe, with seven fractured wings, one spinal fracture, one leg fracture, two “through-and-through” entrance and exit wounds on opposite sides of the body, and four cases of generalized wing trauma.
“This is an especially cruel case, given the number of animals killed outright or apparently mortally wounded by BBs ricocheting around beneath the bridge. Quick escape from the concrete expansion joints of the bridge that the bats inhabit would have been difficult,” said Regional Supervisor Raul Vega of AGFD. “We are now conducting a criminal investigation and actively seeking information leading to full prosecution of whoever is responsible.”