Himalayan monal shifts its call pitch amid human noise in a Kedarnath sanctuary valley

Of the two studies, run over five years ^[7], the voice result comes from a field comparison. Rajeev Lochan, Dinesh Kumar Sharma and Anand Kumar worked in two valleys of the Kedarnath Musk Deer Sanctuary ^[2]. According to the BBC, the monal is changing its pitch to be heard over human noise in a busy valley ^[1]. You cannot switch noise on and off for a wild pheasant, so comparing places is the practical way to get a contrast. The weakness is that there are only two sites. Anything else that differs between the valleys, such as slope, vegetation or the number of birds, moves along with the noise. The BBC account does not give the number of calls recorded, the size of the pitch change or which way it went.

The habitat study is a projection. The team modelled where conditions suit the monal across Uttarakhand and Himachal Pradesh, using the same kind of global climate models and emissions scenarios that the IPCC uses in its assessments ^[4]. Under several scenarios, the suitable habitat keeps shrinking and destabilising through 2100 ^[3]. The model assumes the bird will need the same climate it finds in alpine meadows today, an assumption the BBC calls reasonable but not certain ^[5]. If the monal can tolerate more than it currently uses, the projected losses are too large. If the assumption holds, the study says populations would break into disconnected pockets. That would mean less breeding between groups and a higher risk of long-term decline or local extinction ^[6].

Tourism comes into the story mostly through Lochan's own account. The BBC sums up one study as finding that crowding in the meadows above the tree line is forcing the birds uphill ^[10]. A climate model cannot show on its own who is doing the pushing. Lochan named both causes at once. "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," he said ^[9]. The BBC reports that rapid infrastructure expansion over the past decade has opened up more places and raised visitor numbers ^[14]. To separate the human share of the upslope move from the warming share, you would need bird counts set against counts of people.

Lochan said the team chose the monal, Uttarakhand's state bird ^[8], for its narrow range. It moves with the seasons between the lower montane belt and the high alpine zone, and he calls it a key indicator of ecosystem health in the north-western Himalayas ^[11]. "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 ^[12]. Vishal Singh, an environmental practitioner in the region, framed it as a question: "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?" ^[13]

I think the choice of indicator is sensible. A bird that moves between two altitude zones is exposed to disturbance in both ^[11]. As reported, though, the studies measure the monal alone, so any answer to Singh's question has to come from surveys of the more sensitive species themselves. Singh's own diagnosis is broader. "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," he said ^[15].