|Bird song characteristics respond differently to landscape development at two points in time.
Karina A.Sanchez1, Lauryn Benedict 1, Carla Cicero2, Kristina Fialko3.
1University of Northern Colorado, Greeley, Colorado, USA.2University of California Berkeley, Berkeley, California, USA.3University of Chicago, Chicago, Illinois, USA
In an urbanizing world, animals may need to respond to novel habitats to improve signal transmission to receivers. Studies show that some birds alter the frequency, amplitude, and song structure in urban areas. Songbirds learn their songs from other individuals and this cultural transmission can result in change over time. Urban bird populations may therefore show rapid trajectories in song evolution and variation may result from the combined effects of time and habitat change. In this study, we use historic and recent song recordings to investigate changes in Spotted Towhee (Pipilo maculatus) songs over 45 years in urban and rural areas of Northern California. We found that trill and pre-trill song parts were affected differently by urbanization at the two time-points. Additionally, birds in 1970 adjusted trills by raising maximum frequency and broadening bandwidths, while birds in 2015 narrowed song bandwidths by decreasing maximum frequency in more urban areas. These results suggest that habitat and cultural evolution can act on song elements in complicated ways, that vary over time and suggests that Spotted Towhees can use multiple strategies to alter songs in urban habitats.
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