Bat recording under controlled conditions: A replicable chamber for comparable results

In ecology, bats have become a major subject of study. Some pollinate and disperse the seeds of many tropical plants; some help to control insect populations; a few affect livestock by sucking blood, but in all cases bats are indispensable links in ecosystems. Bats use of sound waves make echolocation calls monitoring a powerful tool for distribution, census, and present studies. This technique depends on having a reliable database of sounds for species identification purposes. Although there are several databases of echolocation sounds; the signal emitted by a bat depends on environmental conditions (vegetation, weather conditions), biotic factors (prey size, movement, defensive measures), and the specific task (seek, flee, pursue, evade, wandering, obstacle avoiding). This variability makes comparisons among databases difficult. A portable chamber made of common materials for in situ recording under controlled conditions is presented. The use of the chamber is proposed as a tool which might help to generate databases that could be reliable compared. Nine species of desert bats from the northwest region of Mexico were recorder using the chamber under controlled conditions and compared with field recordings. The performance of the chamber and the utility of the database generated for filed identification are presented.