A small forest bird found across North America sings differently in response to traffic noise, which could affect the species’ ability to attract mates and defend territory, according to a new study.
Katherine Gentry, a researcher at George Mason University in Virginia, and her colleagues studied the song of the Eastern Wood-pewee, a type of North American flycatcher, in three parks within the Washington, D.C. area.
In a study published by Taylor and Francis Online in the journal Bioacoustics, they describe how the birds immediately responded to traffic noise by adjusting the length and pitch of their songs.
The birds sang shorter songs when there was traffic noise in order to improve the transmission of their calls, the researchers found.
The songs were recorded at locations where the nearby road traffic patterns were either relatively consistent or reduced on a weekly basis for a 36-hour road closure.
“When roads were closed, songs returned to their natural state with broader bandwidth, lower minimum frequencies and longer duration,” the study authors said in a news release.
Although the birds are able to adjust their songs in response to their environment, the altered calls may not get strong responses from other birds and potential mates, researchers say.
The study authors say reducing traffic noise and closing roads in forested areas could help halt the decline of the Eastern Wood-pewee. The species’ numbers in the Washington, D.C. area have reportedly declined by more than 50 per cent in the last 70 years.
The Eastern Wood-pewee is considered a species of “special concern” in Canada.
