Wetlands are highly impacted by land-use changes associated with threats like agriculture and urbanization, however one threat that receives less attention is that of anthropogenic noise. Recently, there has been an increase in the number of studies linking anthropogenic noise to impacts on wildlife. Waterfowl could be at risk for disturbance by automobile noise due to the spread of transit networks into rural areas that waterfowl commonly use as wintering habitat. We tested the response of wintering waterfowl to playback traffic noise at 75 dB in wetland habitats in southwest Arkansas from January through March 2018. Each trial of the experiment consisted of three 20 minutes phases designated as before, during, or after the traffic playback. During each minute of a trial, we recorded the number of birds of each species and the distance of each bird from the noise source. Distance measurements were grouped into bins of 0-25, 25-50, 50-75, and 75-100m. We pooled all species to look at the effects on the entire waterfowl community.
Results/Conclusions
The mean closest distance approached was shorter before the noise playback (18m) compared to during (39m) and after the playback (41m), indicating that birds were more likely to get closer to the speaker before any noise was played. In addition, birds occupied all distance bins equally before the noise was played. However during and after the noise, the proportion of birds in each bin increased with increasing distance from the speaker, with over 85% of birds occupying the two most distant bins during and after the noise playback. Our results suggest that traffic noise disturbs waterfowl by causing them to avoid areas of open water that are near the noise source. This finding highlights the importance of considering anthropogenic noise when selecting sites for new wetlands or considering regulations for existing waterfowl habitat.