Assessing Acoustic Niche Partitioning in a Temperate Forest and Scrub Bird Community

Heiser, Joshua

Assessing Acoustic Niche Partitioning in a Temperate Forest and Scrub Bird Community

Persistent URL

https://dspace.allegheny.edu/handle/10456/56732

Author(s)

Heiser, Joshua

Date Issued

April 2023

Abstract

According to the acoustic niche hypothesis, animals that communicate vocally are expected to modify the timing or frequency of their vocalizations to avoid overlapping in time and frequency with other vocalizing species. In birds, acoustic niche partitioning (ANP) increases with species richness, community intactness, and levels of background noise. Forest and open habitats are expected to differ in their levels of ANP due to differences in how sound propagates between habitats. I investigated ANP in a forest and a scrub bird community using 24 minutes of audio from four forest sites and four scrub sites in northwestern Pennsylvania. ANP was assessed by determining the number of vocalizations that overlapped in time and frequency and comparing the observed number of overlaps to an expected distribution of overlaps generated by randomizing the start time of each vocalization but holding its duration and frequency range constant. Observed overlaps were not significantly lower than the expected distribution of overlaps in any of the sites, indicating that ANP is not occurring within either of the sampled forest or scrub habitats. Failure to detect ANP could be due to differing conditions in temperate vs. tropical environments as well as an artificially high sensitivity to overlap in my methodology. The study indicates temperate birds tolerate some level of acoustic overlap and suggests future conservation efforts should focus on reducing anthropogenic noise in tropical environments, where such noise is more likely to disrupt avian communication systems than in temperate communities.

Major

Biology

Environmental Science

Honors

Biology, 2023

First Reader(s)

Mumme, Ronald L.