An Incidental Take Permit for Endangered Karst Invertebrates in Bexar County, Texas

It has generally been shown that for many temperate insectivorous bats, the time of evening emergence from their day roosts is approximately parallel to sunset. Although this emergence time may vary between species, within species the bats are known to have similar activity patterns. A maternity colony of Myotis velifer (cave bat) in southern Arizona was monitored for four years and an interesting deviation from the emergence pattern was observed. These bats appeared to emerge sooner in the early spring and autumn than in late spring and summer. Besides this variation in the time of emergence, the character of the outflight also changed through the summer period. This roost was then compared to a roost of M. velifer approximately 20 miles south of the maternity colony. The differences and similarities are discussed and possible justification for the pattern variations are proposed. A potential explanation for the different activity patterns could be the reproductive condition of the females at the maternity colony. Other factors such as ambient temperature may also play a role. Probably no one element is the trigger for emergence, but rather a combination of factors may impact bat activity patterns