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United News of India
17 hours ago
- Science
- United News of India
Why do birds sing at dawn? A study from the Western Ghats unravel the morning chorus
New Delhi, June 14 (UNI) Have you ever wondered why so many birds choose quiet, dawn hours to sing the loudest? Intrigued by this mystery, a team of scientists from the Cornell Lab of Ornithology and Project Dhvani in India took it upon themselves to unravel what drives this morning chorus. They discovered that it's not just the calm winds or cooler temperatures that set off this daily routine — it's what the birds eat and how fiercely they defend their territory that make the biggest difference. The team studied 69 bird species across 43 forest sites using advanced audio monitoring technology, revealing that territorial and omnivorous birds are far more likely to sing at dawn. This suggests that social behaviors—not just environmental conditions—are the primary reason for the surge in morning vocal activity. The research titled 'Why is the early bird early? An evaluation of hypotheses for avian dawn-biased vocal activity,' is published in the journal Philosophical Transactions of the Royal Society B. To collect the data, the team placed microphones throughout the forest to automatically record bird vocalizations throughout the day—technology often referred to as passive acoustic monitoring. This technology records audio that researchers later listen to and catalogue which species vocalized during the day, said the study. 'Passive acoustic monitoring allowed us to collect simultaneous acoustic data for 43 locations, over several months. We could not have done this study without it because we needed a lot of data to answer our questions,' said lead author Vijay Ramesh, postdoctoral researcher at the K. Lisa Yang Center for Conservation Bioacoustics, in the study. The other researchers included Pavithra Sundar, Meghana Srivathsa, both from Project Dhvani, Bangalore and Laurel Symes from K Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, New York. The team found that 20 bird species had substantially higher vocal activity at dawn compared to dusk. These dawn singers included species such as Gray-headed Canary-Flycatcher, Greater Racket-tailed Drongo, and Large-billed Leaf Warbler. Only one species, the Dark-fronted Babbler, sang more often at dusk than dawn. Ramesh and his colleagues examined four possible theories to explain why several of the species they studied sang more at dawn compared to dusk. Existing theories suggest that dawn singing is more prevalent due to microclimate conditions such as wind speed and air temperature that would allow birds with high-pitched songs to be heard more clearly over longer distances. Other theories suggest that birds sing more at dawn to defend their territories or to maximize foraging opportunities later in the day when there is more light, or more insect activity. The team gathered additional data from existing literature such as degree of territoriality and diet to examine these four theories alongside the acoustic data they collected in the field. 'We found that highly territorial birds and omnivorous species were much more likely to be active singers during dawn hours," said the scientist. Singing in the early morning hours, the authors suggested, is important for territorial species to advertise and protect their locations. Species that eat insects and fruit (i.e., omnivores) also showed prevalence for singing more at dawn. Ramesh pointed out that omnivores might sing more at dawn because these species are often members of mixed-species foraging flocks where vocal communication is essential for finding food and for warning group members about potential predators nearby. However, he has called for additional research that includes visual observations is needed to confirm his speculation. "Our findings demonstrate that social factors, particularly territoriality and feeding habits, are more important in driving dawn singing behavior than environmental conditions," the scientist said. UNI AJ PRS
Time of India
a day ago
- Science
- Time of India
Birds sing at sunrise to defend their territory and communicate about food: Study
Pune: Birds in the Western Ghats begin their day with a chorus of songs, mainly to protect their space and share important messages like food locations, a study has found. The study conducted in Valparai plateau in the Western Ghats by scientists Vijay Ramesh, Pavithra Sundar, and Meghana Srivathsa from the Cornell Lab of Ornithology and Project Dhvani showed that highly territorial birds sing loudly at dawn to warn others to stay away. Tired of too many ads? go ad free now Some birds also use their morning songs to help their groups stay connected and informed, especially those that eat a mix of insects and fruits. The researchers placed audio recorders at 43 different rainforest sites to capture bird sounds and studied them between March 2020 and January 2021. The team listened closely to bird calls at dawn and dusk. Of the 120 species recorded, they focused on 69 commonly heard species. Among the birds most active at dawn were the Indian blackbird, little spiderhunter, oriental magpie-robin, and purple sunbird. These birds were often heard in the morning and, to a lesser extent, in the evening. The study was published in the Royal Society journal Philosophical Transactions on June 12. Ramesh said, "Bird species vary widely in their diurnal vocalisation patterns, and the drivers of this variation are not well understood. Using passive acoustic monitoring, we examined species-specific vocal activity patterns at dawn and dusk for a tropical bird community in the Western Ghats biodiversity hotspot in India." The scientists tested whether environmental factors such as signal transmission conditions, ambient light, and resource availability, and social factors such as territoriality, best explained patterns of diurnal variation in vocal activity. Tired of too many ads? go ad free now Using multiple autonomous recording units collecting data across numerous locations simultaneously, they can now obtain large amounts of species-specific acoustic data for an entire community. The Western Ghats is home to hundreds of bird species, several of which are rare, endangered, and endemic to this region. The Valparai plateau is situated in the Anamalai hill range within the Western Ghats and primarily consists of mid-elevation tropical wet evergreen rainforests. The plateau is a typical example of a human-modified biodiverse landscape in India and is home to hundreds of species of rare and endemic flora and fauna and supports the livelihoods of thousands of people. Sundar, another scientist who was part of this study, said, "We found that highly territorial birds and omnivorous species were much more likely to be active singers during dawn hours." The authors of the research paper stated that early morning hours were important for territorial species to protect their locations. Species that eat insects and fruit—that is, omnivores—also showed a prevalence for singing more at dawn. Sundar said these species were often members of mixed species foraging flocks, in which vocal communication was essential for finding food and for warning group members about potential predators nearby. However, additional research that includes visual observations is needed to confirm this speculation, Ramesh said. The researcher stated that this study helped them understand how birds communicated and how changes in the environment could affect their natural behaviour. "By listening carefully to nature, researchers are learning not just when birds sing, but why it truly matters," stated Ramesh. Acoustic signals of four species were detected only at dawn—the Indian blackbird (Turdus simillimus), the little spiderhunter (Arachnothera longirostra), oriental magpie-robin (Copsychus saularis), and the purple sunbird (Cinnyris asiaticus). Twenty species had vocal activity that was substantially higher at dawn. Notable representatives include the grey-headed canary-flycatcher (Culicicapa ceylonensis), greater coucal (Centropus sinensis), large-billed leaf warbler (Phylloscopus magnirostris), and puff-throated babbler (Pellorneum ruficeps). The dark-fronted babbler (Rhopocichla atriceps) was the only species with significantly higher vocal activity at dusk.
