Two studies by Indian researchers have confirmed what anyone who's tried to have a conversation next to a tour bus already suspected: the Himalayan monal, a pheasant with feathers in green, blue and copper, is being forced to change both where it lives and how it talks, thanks to a sharp increase in human activity. The bird, which serves as the state bird of Uttarakhand and the national bird of Nepal, is apparently less thrilled about its cultural icon status than the tourism brochures suggest.
The first study, led by Dr Rajeev Lochan and conducted over five years, found that the monal is being pushed higher into the mountains as its natural habitat in the alpine meadows above the tree line gets crowded. Climate change is projected to continue shrinking and destabilising the bird's habitat across the Indian Himalayas through 2100 under multiple climate scenarios, according to models based on the same global climate models and emissions scenarios used by the Intergovernmental Panel on Climate Change (IPCC). Researchers modelled shifts in suitable habitat across Uttarakhand and Himachal Pradesh. The birds' seasonal migration between the lower montane zone and high-elevation alpine zones may become increasingly difficult, as they're forced into smaller, fragmented areas. Their populations would be scattered in disconnected pockets, reducing breeding between groups and increasing the risk of long-term decline or local extinction, which is already a threat.
The second study, also conducted by Lochan along with Dinesh Kumar Sharma and Anand Kumar from Hemvati Nandan Bahuguna Garhwal University, focused on the bird's behavioural changes. Researchers recorded more than 700 monal calls across two valleys in the Kedarnath Musk Deer Sanctuary in Uttarakhand - Chopta, a tourist spot with busy traffic and visitors, and the largely quiet Madmaheshwar - using microphones and passive recording devices. They measured pitch, call length and background noise levels for a year from April 2023. Birds in noisy environments consistently produced calls with significantly higher peak frequencies compared with those in quieter habitats. The monal in Chopta also produced shorter call durations, likely to cut through low-frequency human noise from traffic and tourist footfall.
Lochan noted that subtle changes in pitch could be picked up by recording devices but might go unnoticed by the human ear. He clarified that this doesn't mean the species has undergone a permanent or evolutionary change in its vocal frequency; rather, it suggests behavioural flexibility in response to different acoustic environments. Bird calls are one of the most sophisticated forms of sound-based communication in the natural world, and significant changes can interfere with mating success, among other things.
"These two studies give a useful warning for other more vulnerable species - if the monal is forced to change both its voice and its address, how are the more sensitive species responding?" said Vishal Singh, an environmental practitioner working on ecology and climate issues in the Himalayas. Lochan told the BBC they chose to study the monal because the bird has a narrow habitat range, moving seasonally between the lower montane zone and high-elevation alpine zones. This makes it a key indicator of ecosystem health in the north-western Himalayas. "If the species is facing issues on this particular landscape, there might be a chance that the ecological disturbances are affecting other birds too," he said.
The monal can be seen as a stand-in for the health of a fragile Himalayan ecosystem pushed to a tipping point due to unregulated tourism and heavy urbanisation. While the region has always drawn tourists, trekkers and researchers given its scenic landscape and biodiversity, rapid infrastructure expansion in the past decade has made more places accessible, increasing footfall and disrupting wildlife. This, coupled with mounting human pressures, suggests that climate change is emerging as another major threat to the region's already vulnerable biodiversity. "There are a lot of factors at play but at a broader level, the problem is that the economic development of the region is not aligned to its ecological integrity," Singh said.
Anjal Prakash, a public policy professor at FLAME University and contributor to IPCC reports, put it more poetically: "When a species must raise its pitch to be heard over tourist traffic, or climb higher as meadows turn crowded, it reveals how human pressure is rewriting the rules of life in the Himalaya." He added, "In listening to the monal, we hear the Himalayas asking for space, silence and care." Lochan says he and his team consider this a preliminary study and hope to expand its scope and depth. The research comes with the caveat that it is not conclusive on ecological consequences, and more research is needed. But together, the two studies signal broader ecological stress across the Himalayas - and a bird that's apparently had just about enough of our noise.