A sharp rise in human activity is changing the way a Himalayan bird lives and communicates, with two studies by Indian researchers highlighting the growing pressure on the species.

The Himalayan monal, a pheasant native to the mountain forests of the Himalayas, is deeply woven into the region’s culture, folklore and identity. The striking bird, whose male has distinctive green, blue and copper plumage, is the state bird of India’s Uttarakhand and the national bird of Nepal, reflecting its cultural importance across the Himalayas.

But researchers say infrastructure development, tourism and human-generated noise are putting increasing pressure on the bird. One study found that climate change and human encroachment could push the monal into smaller, higher-elevation habitats, while another found that birds living in noisier areas alter their calls to communicate in environments dominated by traffic and tourist activity.

According to the BBC, researchers from Uttarakhand conducted the two studies over five years, identifying key threats to the species and highlighting wider concerns about the health of Himalayan ecosystems.

One study found that monals are being pushed towards higher elevations as their natural habitat in alpine meadows becomes increasingly crowded and fragmented. The other found that the birds change their vocal behaviour in response to human-generated noise in a busy tourist valley.

“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.

Dr Rajeev Lochan, the lead researcher on both studies, told the BBC that the monal was chosen because of its relatively narrow habitat range. The bird moves seasonally between lower montane areas, an ecological belt on the lower slopes of mountains, and high-elevation alpine zones.

This makes the species an important indicator of ecosystem health in the north-western Himalayas, he said.

“If the species is facing issues on this particular landscape, there might be a chance that the ecological disturbances are affecting other birds too,” Lochan said.

The monal can therefore be viewed as a stand-in for the health of a fragile Himalayan ecosystem that is under growing pressure from tourism, urbanisation and infrastructure development.

The Himalayas have long attracted tourists, trekkers and researchers because of their dramatic landscapes and biodiversity. But rapid infrastructure expansion over the past decade has made previously inaccessible areas easier to reach, increasing visitor numbers and disrupting wildlife.

Climate change is adding another layer of pressure to the region’s already vulnerable ecosystems.

“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.

According to the first study, climate change is projected to continue shrinking and destabilising suitable habitat for the Himalayan monal across the Indian Himalayas through 2100 under multiple climate scenarios.

The birds are currently found in alpine meadows high above the forests. These areas are among the Himalayas’ most important seasonal grazing grounds and are also rich in biodiversity.

The researchers modelled how climate change could alter the distribution of suitable monal habitat across the Indian Himalayan region, particularly in Uttarakhand and Himachal Pradesh. The study used global climate models and emissions scenarios similar to those used in assessments by the Intergovernmental Panel on Climate Change (IPCC), the UN’s climate science body.

“These birds are now slowly moving upwards in the Himalayas as the snow is melting and vegetation is growing, making the area accessible to them. They are anyway being pushed upwards as their natural habitats in alpine meadows are being encroached upon by humans,” Lochan said.

The researchers’ model assumes that the climatic conditions currently associated with alpine meadows will continue to be suitable for the birds in the future, although this is not certain.

Climate-driven changes could make the monal’s seasonal movements increasingly difficult, forcing the birds towards higher elevations and into smaller, fragmented areas.

As populations become scattered across disconnected pockets of suitable habitat, opportunities for breeding between groups could decline. This could increase the risk of long-term population declines or local extinctions, the study said.

The second study, also led by Lochan and conducted with Dinesh Kumar Sharma and Anand Kumar of Hemvati Nandan Bahuguna Garhwal University, examined changes in the bird’s behaviour in response to human-generated noise.

The researchers studied monals in two valleys in Uttarakhand’s Kedarnath Musk Deer Sanctuary. One was Chopta, a popular tourist destination with heavy traffic and visitor activity, while the other was the relatively quiet Madmaheshwar valley.

Over the course of a year from April 2023, the researchers recorded more than 700 monal calls at the two sites using microphones and passive recording devices. They then measured the pitch and duration of the calls, along with background noise levels.

The study found that birds living in noisier environments consistently produced calls with significantly higher peak frequencies than those in quieter habitats.

The changes were subtle enough to go largely unnoticed by the human ear but were detectable through acoustic recording equipment.

“This does not mean that the species has undergone a permanent or evolutionary change in its vocal frequency; rather, our findings suggest behavioural flexibility in response to different acoustic environments,” Lochan said.

Monals in Chopta also produced shorter calls than those recorded in the Madmaheshwar valley. The researchers suggest this may help the birds communicate more effectively against the low-frequency noise produced by traffic and tourist activity.

Bird calls are among the most sophisticated forms of sound-based communication in the natural world. Changes in these signals could potentially affect important behaviours, including communication between potential mates and rivals.

“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,” said Anjal Prakash, a public policy professor at FLAME University and a contributor to IPCC reports.

Lochan said the researchers consider the vocalisation study preliminary and hope to expand its scope and depth through further research.

The studies do not establish definitive ecological consequences, and the researchers acknowledge that more work is needed to understand how the observed changes could affect the species in the long term.

Taken together, however, the findings point to broader ecological stress across the Himalayas, where climate change and expanding human activity are increasingly reshaping wildlife habitats and behaviour.

“In listening to the monal, we hear the Himalayas asking for space, silence and care,” Prakash said.