Rydell, J. 1993: Variation in the sonar of an aerial-hawking bat (Eptesicus nilssonii). Ethology 93, 275–284.
Variation in the Sonar of an Aerial-hawking Bat (Eptesicus nilssonii)
Article first published online: 26 APR 2010
1993 Blackwell Verlag GmbH
Volume 93, Issue 4, pages 275–284, January-December 1993
How to Cite
Rydell, J. (1993), Variation in the Sonar of an Aerial-hawking Bat (Eptesicus nilssonii). Ethology, 93: 275–284. doi: 10.1111/j.1439-0310.1993.tb01209.x
- Issue published online: 26 APR 2010
- Article first published online: 26 APR 2010
- Received: November 12, 1992; Accepted: January 5, 1993
Echolocation calls from 10 individually marked female northern bats (Eptesicus nilssonii) were recorded as the bats foraged at three distinct feeding sites (territories) near their maternity roost in southern Sweden (57° N). In addition, recordings of unmarked bats were made in northern Sweden (65° N). The frequency at maximum amplitude of “search phase” echolocation pulses was bimodally distributed, with peaks around 29–30 kHz and 31–32 kHz and was negatively correlated with pulse duration. The frequency at maximum amplitude was related to flight altitude (bats used higher frequencies when they flew near the ground) and also differed among the feeding sites. Hence, much of the variation, probably including regional differences, was behavioural and is interpreted as short term (in the order of s or min) adaptation to current foraging situations. Variation among individual bats, caused by age and size, seemed to be of less importance. Individuals did not use exclusive frequency bands.