The city has fallen silent during the early hours as it has lost its long-familiar dawn chorus, the layered symphony of birdsong, during sunrise. As temperatures climb beyond 440 C to 450 C, the vocal activity of common urban bird species has reduced. The House Crow, Asian Koel, Laughing Dove and Sparrow, which typically begin their calls between 5.15 am and 5.30 am from March to June, are now nearly absent in voice. Through dawn chorus, birds have been utilising the early morning window for mate attraction, territorial assertion, and flock coordination under favourable acoustic conditions.

 

Dr Sharyu V Ghonmode-Fulzele, Entomologist and Professor, Shivaji Science College, noted that this chorus, which has now been disrupted, was a deeply observed seasonal phenomenon. “Crows would call resonantly from neem and peepal trees at first light, followed by the koel’s distinctive notes from higher branches. These sounds historically functioned as natural indicators of seasonal transitions, including the ripening of mangoes,” she explained. Dr Fulzele explained that male koels typically vocalise between March and June as part of their breeding cycle, while crows construct nests from February to May. By late June and July, koel chicks hatch, and vocal activity naturally tapers as adult birds shift their focus to feeding. However, even during these peak breeding months, calls now diminish or cease entirely when temperatures exceed 440 C to 450 C. “Birds suppress vocalisation under such extreme conditions to conserve energy and prevent dehydration, as calling elevates metabolic demand and accelerates water loss,” she added. 

 

Normally, high-rise trees provide essential nesting sites as well as elevated calling perches. Dr Fulzele explained that hence, deforestation for infrastructural development in urban areas is causing the depletion of birds’ population drastically. Dr Tiple explained that this absence diminishes breeding habitats and also erodes the acoustic advantage necessary for effective bird communication. “Installation of mobile towers and the expansion of 5G infrastructure are also being observed as potential disturbances that may disorient birds within their habitats,” Dr Fulzele added. Addressing possible interventions, she emphasised that providing water bowls, ensuring access to food sources, safeguarding existing tree cover, and refraining from pruning during the breeding season from March to June could help revive bird activity. 

 

“During summer season, a house crow may require water intake every two hours. When accessible water sources are scarce in residential areas, birds migrate to spaces with reliable water availability, such as lakes, canals, nullahs, and gardens,” Dr Sharyu V Ghonmode-Fulzele said. Dr Ashish Tiple, an Ecologist and Associate Professor and Head, Lack of water sources forces birds to migrate Contd from page 1 PG Department of Zoology, Dr R G Bhoyar Arts, Commerce and Science College, Seloo, Wardha, corroborated these observations. Referring to key water bodies such as Ambazari Lake and Futala Lake, he highlighted a decline in migratory bird populations due to shrinking resources and escalating environmental stress.