Himalayan Monal Adapts Its Calls to Noisier Environments

The Himalayan monal, Uttarakhand's state bird, is demonstrating a remarkable adaptation to human-generated noise in its habitat. Researchers have found that these birds are calling at higher frequencies and for slightly longer durations in parts of the Himalayas made noisier by traffic, tourists, pilgrims, and other human activity. This finding, published in Behavioural Processes in August 2025 by Rajeev Lochan, Dinesh Kumar Sharma, and Anand Kumar of Hemvati Nandan Bahuguna Garhwal University, suggests the monal is changing its voice to cope with an increasingly loud soundscape.

The study involved recording 719 monal calls between April 2023 and June 2024, comparing a relatively quiet stretch of Madmaheshwar Valley with the busier Chopta Valley within the Kedarnath Musk Deer Sanctuary. The researchers utilized directional microphones and passive acoustic monitoring devices, including AudioMoth recorders, particularly during the birds' more vocal morning and evening periods. They found that monals in noisier habitats produced calls with higher peak frequencies, with the median peak frequency in quieter areas being around 171 Hz lower than in the noisier ones, and a statistical model explaining about 73.4% of the variation at the 95th quantile.

This vocal shift is likely a response to 'acoustic masking,' where background noise overlaps with an animal's communication signal, making it harder to detect. By shifting calls to higher frequencies and making them slightly longer, the monal appears to be attempting to reduce this masking effect and maintain communication crucial for finding mates and defending territory. While the study doesn't yet establish if these altered calls impact mating success or population numbers, it highlights the bird's capacity to adjust to environmental changes without moving away from its native range, which spans from Afghanistan to Bhutan across the Himalayas.

However, a separate 2025 study by the same researchers, published in Scientific Reports, examined the monal's future habitat suitability under climate change scenarios. Using species-distribution modeling and 5,122 occurrence records, they projected that precipitation during the coldest quarter is a critical factor. Under one scenario, over 14% of previously suitable habitat could become unsuitable by 2041–2070, with further losses projected towards the end of the century under a high-emissions scenario. The monal, currently classified as Least Concern on the IUCN Red List, inhabits alpine and subalpine areas, oak-mixed forests, and steep mountain slopes between 2,400 and 4,500 meters, environments increasingly threatened by climate change, land-use shifts, infrastructure development, and tourism.

Why it matters: This adaptation shows wildlife coping with human impact, but also raises questions about long-term costs.

Editor's note: The draft is a comprehensive and accurate summary of the research study provided in the source material.