Cicada sound impacts avian dawn chorus in a subtropical forest of Taiwan

Abstract

Acoustic space is a limited resource for animal communications. To reduce signal competition, animals could differentiate their acoustic frequency range or time to produce sound. Many birds call or sing at dawn for higher signal transmission efficiency. However, in tropical and subtropical forests, the dawn chorus were frequently interferenced by cicadas. In order to examine the effect of cicadas on the avian dawn chorus, we used automated acoustic recorders at subtropical forest of Yangmingshan National Park, Taiwan, to monitor acoustic signals of eight bird species and three cicada species. We found that all bird species postponed their acoustic activities during cicada's breeding season. Meanwhile, we also found frequency partitioning of acoustic signals between birds and cicadas when their acoustic signals overlapped temporally. The results show that cicadas could play a crucial role in the avian dawn chorus. Birds would delay their signal producing time and acoustic frequency to partition the acoustic niche.