International Research Fellowship Program: Effects of Ambient Noise on Song-learning and Mate Choice in Zebra Finches

Kight Caitlin R, The Plains OH

Investigators

Abstract

0965125 Kight The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-four-month research fellowship by Dr. Caitlin Kight to work with Dr. Sasha Dall at the University of Exeter in the United Kingdom. Anthropogenic noise has recently been associated with changes in several song characteristics of wild bird species. Unfortunately, nearly all of the current studies on this topic focus on adult males; it is not yet known whether, or how, anthropogenic noise might impact juvenile or female birds. Further, while birds have been observed to sing different songs in noisy environments, it is not clear whether this is because they learn different vocalizations in these environments or because they possess vocal plasticity allowing them to make spontaneous adjustments to their songs in response to their current environments. Because birds use song to attract mates and defend territories, changes in these vocal signals could reduce their ability to communicate effectively, thus reducing breeding success. However, this possibility has yet to be explored. This study focuses on a captive population of zebra finches (Taeniopygia guttata) in order to explore three questions related to song learning and ambient noise. First, does the presence of ambient noise increase errors in song learning by male zebra finches? Second, do adult birds display vocal plasticity in response to variable ambient noise conditions? Third, does ambient noise impact female mate preference? To investigate this, juvenile zebra finches are raised across an ambient noise gradient, such that some birds are better able to hear tutor song. Males? final, crystallized songs are compared to those of their tutors, in order to measure whether the interfering ambient noise reduced the birds? ability to accurately copy vocalizations. The birds are then ?migrated? to a new noise habitat, and their songs are recorded under the new ambient noise conditions. This will facilitate an exploration of whether individual singers display vocal plasticity under differing acoustic environments (indicating that all males should be equally ?prepared? for the noise conditions on their adult territories), or whether they will maintain the same song characteristics throughout their adult lives (indicating that noise conditions in natal habitats could ?prime? some males for vocal success or failure in their adult territories). Finally, recordings are collected from males raised across the ambient noise spectrum, and used in mate preference trials involving females who have also been raised across the ambient noise gradient. These trials are designed to test whether female preference, like male song learning, is influenced by ambient noise conditions?a possibility that could impact breeding success and therefore have widespread population consequences. Given the steady increases in human land use, this project provides a timely elucidation of how the mechanisms that shape animal behavior could interact with changes in anthropogenic land use to impact population dynamics in wild birds. We are only beginning to understand the impacts of anthropogenic noise pollution, both in an evolutionary and a management sense. These future studies will further our understanding of the ways in which current noise pollution impacts avian communication, which may also elucidate the environmental pressures that shaped avian vocal signals in the past. This research will also indicate whether changes in acoustic conditions will have secondary impacts on population size and persistence. These data are essential for making management decisions that minimize the impacts of human disturbance. This may include the erection of sound barriers or the creation of buffer zones during breeding seasons.