Researchers at Hemvati Nandan Bahuguna Garhwal University recorded over 700 monal bird calls across two Uttarakhand valleys, discovering that birds in noisy tourist spots like Chopta produce higher-pitched and shorter calls to cut through human noise compared to those in quieter habitats like Madmaheshwar.
A striking Himalayan bird species is altering its vocalisations in response to human-generated noise, according to research conducted in Uttarakhand. The study focuses on behavioural changes in the monal, tracking how acoustic pressures from tourism and traffic affect avian communication.
Acoustic Shifts in Chopta and Madmaheshwar
The research was conducted by Lochan, Dinesh Kumar Sharma, and Anand Kumar, who are based at the Hemvati Nandan Bahuguna Garhwal University. Investigators examined two distinct valleys within the Kedarnath Musk Deer Sanctuary: Chopta, which features busy traffic and tourist activity, and Madmaheshwar, which remains largely quiet.
Beginning in April 2023, the team utilised microphones and passive recording devices to capture more than 700 monal calls over the course of a year, subsequently measuring pitch, call length, and background noise levels. Birds residing in noisy environments consistently delivered calls with significantly higher peak frequencies than individuals situated in quieter habitats. Monals in Chopta produced shorter call durations than those in the Madmaheshwar valley, an adjustment likely designed to cut through low-frequency human noise driven by traffic and tourist footfall.
According to the findings, these subtle shifts in pitch are easily detected by recording devices, though they might easily escape the human ear. Researchers noted that the adjustments do not indicate a permanent or evolutionary alteration in the species’ vocal frequency.
Broader Ecological Pressures in the Himalayas
Bird calls represent one of the most sophisticated forms of sound-based communication in the natural world. Significant disruptions to these signals can interfere with critical life events, including mating success.
While the team highlights that this initial study is not yet conclusive regarding broader ecological consequences and requires further investigation, the findings point toward widespread environmental stress across the region. Lochan and his co-researchers intend to expand both the scope and depth of the project.
