An increase in song pitch of eastern great tits (Parus minor) in response to urban noise at Seoul, Korea

Abstract

Anthropogenic noise may mask effective vocal signal transmission by birds, particularly in notes occurring in lower frequencies. Previous studies have shown a correlation of increased urban noise levels, higher minimum frequency, and lowered bandwidth in Great Tit song (Parus major). We therefore studied the effect of urban noise pollution on the song characteristics of the closely related Eastern Great Tit (EGTs, Parus minor) at Hongneung experimental forests (HEFs) in the metropolitan urban of Seoul, Korea. We analysed the song characteristics of breeding territories of EGTS in total 13 individuals recorded including four individuals at high noise group. EGTs singing in noisier locations exhibited higher minimum & maximum frequency, and lower note & strophe length, and higher bandwidth, replicating the different findings of Great Tits. This data also suggests that several individuals at high noise location exhibited a non-typical song type indicative of structural adaptation to higher noise levels. Although the mechanisms of these correlations are as yet undetermined, it is likely that behavioural plasticity may play a role of vocal signal adaption in an increasingly urbanizing Korea.