So much for the city: Urban-rural song variation in a widespread Asiatic songbird

Abstract

Song plays a fundamental role in intraspecific communication in songbirds. The temporal and structural components of songs can vary in different habitats. These include urban habitats where anthropogenic sounds and alteration of habitat structure can significantly affect songbird vocal behavior. Urban-rural variations in song complexity, song length and syllable rate are not fully understood. In this study, using the oriental magpie-robin (Copsychus saularis) as a model, we investigated urban-rural variation in song complexity, song length, syllable rate, syllable length and inter-syllable interval. Comparing urban and rural songs from 7 countries across its natural Asiatic range (Bangladesh, India, Malaysia, Nepal, Singapore, Sri Lanka and Thailand), we found no significant differences in oriental magpie-robin song complexity. However, we found significant differences in temporal song variables between urban and rural sites. Longer songs and inter-syllable intervals in addition to slower syllable rates within urban sites contributed the most to this variance. This indicates that the urban environment may have driven production of longer and slower songs to maximize efficient transmission of important song information in urban habitats.

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“…There were also three positive interaction effects between distance to buildings and distance to road; distance to road and temperature, and relative humidity and temperature on the time interval between strophes. The time interval between strophes found in current study was also different from that of Hill et al (2018) that compared songs of the same species at urban and rural areas from seven countries (i.e. Bangladesh, India, Malaysia, Nepal, Singapore, Sri Lanka and Thailand).…”

“…The difference in song frequency and structure produced by the Oriental Magpie Robins found in the current study in Malaysia and previous studies in Sri Lanka (i.e. a suburban area), Thailand (a rural area) and India (a wildlife sanctuary) may be caused by different habitat structure which can be a main factor in shaping the bird songs (Boncoraglio & Saino 2007;Hill et al 2018). The acoustic adaptation hypothesis predicts that low frequency and long elements are linked to habitat with complex vegetation structure while high frequency and short elements are likely to be obtained in habitat with herbaceous coverage (Morton 1975).…”

“…Bangladesh, India, Malaysia, Nepal, Singapore, Sri Lanka and Thailand). Hill et al (2018) found that urban environment may cause the Oriental Magpie Robin to produce longer and slower songs to maximize the efficiency of transmission in urban habitat. In contrast, this study found that individuals at sites involved in current study in Malaysia sang slower at sites with rural area characteristics (i.e.…”

Cities as evolutionary experiments

“…A 2018 study found that the oriental magpie-robin, a songbird common in South and South-East Asia, changed its tune when living in the city [3]. Cities are also very noisy and some birds have found ways to cope with it.…”

“…Cities are also very noisy and some birds have found ways to cope with it. A 2018 study found that the oriental magpie-robin, a songbird common in South and South-East Asia, changed its tune when living in the city [3]. Researchers studied the songs of birds from rural and urban settings across multiple Asian cities.…”