Changes of Birds’ Acoustic Activity in Urban Environment

Artificial lighting and anthropogenic noise are known to be important negative factors influencing urban biodiversity. Prolonged daily acoustic activity of diurnal songbirds in cities is one of the reported effects of light and noise pollution. However, there is a lack of data on full daily activity patterns for communities of birds in urban areas. In this study we compared daily activity of several common songbird species in urban and natural environment. We noted vocalizations during the dark hours for all studied species in the urban area. At the same time, in natural environment these species didn’t demonstrate such activity. Additionally, we assessed the daily variations of biophony level and two acoustic index values (Bioacoustic index (BI) and Normalized Difference Soundscape index (NDSI)) for both sites. The biophony level during dark hours was significantly higher in an urban green area, reflecting night vocalizations of birds. BI proved to be a good indicator suitable for assessing and monitoring changes of songbird activity in cities. © 2025 Elsevier B.V., All rights reserved.