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Black Capped Chickadee - Anthropogenic Noise Pollution - Discussion I

Submitted by drosen on Thu, 04/19/2018 - 10:39

We conclude that the varied levels of noise pollution observed at the feeders under study resulted in notable differences in response to mobbing calls. Local individuals at the quiet feeder readily responded to all mobbing calls as well as a number of additional individuals that were not present prior to the experimental mobbing calls. Furthermore, mobbing calls played by the noisy feeder with louder background noise elicited a fractional response with only a small portion of the local fauna responding to the call. This difference suggests that black-capped chickadees (BCCH) in close proximity of the quiet feeder as well as individuals outside visible range were able to hear and appropriately respond to the mobbing calls being played while those within close proximity the loud feeder were unable to appropriately respond. It is less likely that individuals outside of our visual perimeter were able to hear and respond to the mobbing calls in the high decibel area due to the elevated levels of background noise. Of note, another variable that could have been controlled was the specific mobbing call used. BCCH are able to determine perceived threat and relay this information via adjusting the syllable composition and rate of their mobbing call (Baker et al., 2002). By using a mobbing call that typically warrants a vigorous response we would expect to observe a larger experimental response, potentially in higher decibel areas.