Separating the noise from the noise: A finding in support of the Niche Hypothesis, that birds are influenced by human-induced noise in natural habitats

Controlling for the confounding influence of physical disturbance, it was possible to test the hypothesis that ambient noise alone would play a role in structuring bird communities in riparian habitats in Boulder Colorado, USA. Point counts of birds were conducted in open spaca/minimally disturbed, residential, commercial and industrial neighborhoods. Within the same disturbance parameters and land use, species richness and PIF scores (a weighted value based on species' importance) consistently and significantly decreased as ambient noise increased. These results can be viewed as support for the Niche Hypothesis (Krause 1987, 1998), that wildlife species' acoustic niches are adversely affected by human-induced noise pollution. (C) 2001 International Society for Anthrozoology.