60% of bird species in India have declined over 30 years: Report

New Delhi: Of the 338 bird species studied in India for changes in numbers over the last 30 years, 60 percent have experienced a decline, says a new report based on data from about 30,000 birdwatchers across the country.

Also, 40 percent (142) of the 359 species evaluated for change over the last seven years have declined, according to the report titled ”State of India’s Birds”.

The assessments rely on three indices: two are related to the change in abundance — long-term trend (change over 30 years) and current annual trend (change over the past seven years) — and the third is a measure of distribution range size within India.

The researchers involved in the study said they do not have specific reasons for each species’ decline, and stressed the need for rigorous research to find out why this is happening.

”Also, it is not clear if there is a link between the increase in certain species and the decline in the others,” one of the conservationists said.

Of the total of 942 species evaluated, long-term trends could be determined for 338 species. Of these, 204 species have declined, 98 are stable and 36 have increased, says the report published by a group of 13 government and non-government institutions, including the Bombay Natural History Society (BNHS), the Wildlife Institute of India (WII), the Zoological Survey of India (ZSI), and the Wildlife Trust of India (WTI).

Current annual trends could be determined for 359 species, of which 142 have declined (64 rapidly), 189 are stable, and 28 have increased.

The report stresses the need for urgent action to conserve the most critically threatened species in the country: Jerdon’s Courser, Great Indian Bustard, White-bellied Heron, Bengal Florican, and Finn’s Weaver.

It classifies 178 species, including Northern Shoveler, Northern Pintail, Common Teal, Tufted Duck, Greater Flamingo, Sarus Crane, Indian Courser and Andaman Serpent Eagle, as ”high conservation priority”.

Fourteen species, including Indian Roller, Common Teal, Northern Shoveler and Common Sandpiper, have dropped by 30 per cent or more and have been recommended for IUCN Red List reassessment, the report says.

Generalist species like feral Rock Pigeon, Ashy Prinia, Asian Koel and Indian Peafowl are doing very well. Other common species like the Baya Weaver and Pied Bushchat are relatively stable, according to the report prepared using the data uploaded to the online platform eBird.

Habitat specialists — particularly birds of grasslands and other open habitats, wetlands, and woodlands — are declining rapidly.

In terms of diet, carnivores, insectivores, and granivores are declining more rapidly than omnivores or fruit-and-nectar eaters, the report shows.

The long-term decline of specific groups, including raptors and insectivorous birds, hints at toxic chemicals. Recent work on bird declines in Europe points to agricultural intensification, particularly pesticide and fertiliser use, it says.

The report notes migratory species are under greater threat than non-migrants while species endemic to the Western Ghats-Sri Lanka region are faring worse than others.

Certain groups of birds are faring particularly poorly, including open habitat species like bustards and coursers, riverine sandbar-nesting birds like skimmers and some terns, coastal shorebirds, open-country raptors, and a number of ducks.

It is quite likely that habitat degradation has contributed to population declines of forest specialist species, the report says.

”The finding that endemic species are faring poorly is worrying, since their existence rests entirely in our hands,” M Ananda Kumar, Executive Director, Nature Conservation Foundation, said in response to the report.

Ritesh Kumar, Director, Wetlands International-South Asia, said the status of many wetland birds, including ducks and shorebirds, is worrying, and points to the conservation needs of their habitats and ecological corridors.

The report highlights a clear impact on Indian birds due to habitat loss caused by urbanisation, monocultures, and infrastructure development over the past few decades.

While the loss and degradation of forests have been well-studied, other endangered habitats like deserts, grasslands, and marine and coastal areas have received limited research attention.

In the only study focused on the Himalayan region, the effects of climate change on birds’ population levels are highly evident. The threat to certain species due to hunting and illegal trade is substantial, although the impacts on more common species remain less clear, it says.