The song of a vocal mimic reflects changes in avian acoustic communities across an urban gradient
Faculty Advisor Name
Dana L. Moseley
Department
Department of Biology
Description
Urban landscapes present problems for wildlife including highly modified habitat, anthropogenic noise pollution, and competition for suitable habitat. These novel selection pressures can filter species present in urban habitats or result in changes to behavior. Recent studies show some bird species sing differently (louder, higher pitch, faster) in noisier urban areas compared to quieter, more rural areas. We investigated how the level of urbanization affects 1) bird species composition, and 2) the assemblage of species that a songbird mimics from the local bird community. We studied gray catbirds, Dumetella carolinensis, across an urban gradient (Washington DC to Virginia, United States) and predicted that catbirds in urban habitats would mimic fewer species or simply mimic more urban-adapted species. Model selection showed that avian community composition was best predicted by urbanization level (measured by impervious surface, canopy cover, and noise level). The species composition of catbird mimicry was best predicted by bird community, suggesting mimicry reflects the local avian community. Since urbanization level was found to significantly predict avian community composition, this supports that urbanization is indirectly affecting catbird song by influencing the community of sounds available for catbirds to mimic. Catbirds living in habitats of varying levels of urbanization have significantly different songs from one another due to their surrounding communities differing. Because song plays a role in reproductive success through mate attraction and territorial defense, these differences in catbird song could have implications for their ability to persist in urban areas.
The song of a vocal mimic reflects changes in avian acoustic communities across an urban gradient
Urban landscapes present problems for wildlife including highly modified habitat, anthropogenic noise pollution, and competition for suitable habitat. These novel selection pressures can filter species present in urban habitats or result in changes to behavior. Recent studies show some bird species sing differently (louder, higher pitch, faster) in noisier urban areas compared to quieter, more rural areas. We investigated how the level of urbanization affects 1) bird species composition, and 2) the assemblage of species that a songbird mimics from the local bird community. We studied gray catbirds, Dumetella carolinensis, across an urban gradient (Washington DC to Virginia, United States) and predicted that catbirds in urban habitats would mimic fewer species or simply mimic more urban-adapted species. Model selection showed that avian community composition was best predicted by urbanization level (measured by impervious surface, canopy cover, and noise level). The species composition of catbird mimicry was best predicted by bird community, suggesting mimicry reflects the local avian community. Since urbanization level was found to significantly predict avian community composition, this supports that urbanization is indirectly affecting catbird song by influencing the community of sounds available for catbirds to mimic. Catbirds living in habitats of varying levels of urbanization have significantly different songs from one another due to their surrounding communities differing. Because song plays a role in reproductive success through mate attraction and territorial defense, these differences in catbird song could have implications for their ability to persist in urban areas.
