Calls in the Forest: A Comparative Approach to How Bats Find Tree Cavities

Although suitable tree cavities are a particularly critical resource for forest bats (Kunz & Lumsden 2003), how bats search for and find new roosts is still poorly known. The first study to explore this topic revealed that for the fast flying but not very manoeuvrable noctule (Nyctalus noctula), finding cavity entrances by echolocation is a difficult task (Ruczyński et al. 2007). Additional visual, olfactory or temperature cues did not or only marginally improve the bats’ performance. By contrast, conspecific echolocation calls emanating from the roost entrance clearly helped N. noctula in detecting and localizing tree holes. This finding underlines the double function of echolocation for echo-based orientation and communication (e.g. Barclay 1982; Fenton 2003; Siemers 2006; Jones 2008). While Correspondence Ireneusz Ruczyński, Mammal Research Institute, Polish Academy of Sciences, Waszkiewicza 1, 17-230 Białowie _ za, Poland. E-mail: [email protected]