JOURNAL OF ANIMAL ECOLOGY, volume 73, issue 3, 2004
http://www.blackwell-synergy.com/rd.asp?code=JAE&goto=journal
Brumm, Henrik (2004):
The impact of environmental noise on song amplitude in a territorial bird.
Journal of Animal Ecology 73 (3), 434-440.
Summary
1. The impact of environmental background noise on the performance of
territorial songs was examined in free-ranging nightingales (Luscinia
megarhynchos Brehm). An analysis of sound pressure levels revealed that males
at noisier locations sang with higher sound levels than birds in territories
less affected by background sounds.
2. This is the first evidence of a noise-dependent vocal amplitude regulation
in the natural environment of an animal.
3. The results yielded demonstrate that the birds tried to mitigate the
impairments on their communication caused by masking noise. This behaviour may
help to maintain a given transmission distance of songs, which are used in
territory defence and mate attraction. At the same time, birds forced to sing
with higher amplitudes have to bear the increased costs of singing.
4. This suggests that in songbirds the level of environmental noise in a
territory will contribute to its quality and thus considerably affect the
behavioural ecology of singing males.
--
|