Facing threats:Nilgiri Pipit, a species of High Conservation Concern is currently suffering a decline.File Photo  

Over a fifth of India’s bird diversity, ranging from the Short-toed Snake Eagle to the Sirkeer Malkoha, has suffered strong long-term declines over a 25-year period, while more recent annual trends point to a drastic 80% loss among several common birds, a new scientific report jointly released by 10 organisations said on Monday.

The State of India’s Birds 2020 (SoIB) assessment raises the alarm that several spectacular birds, many of them endemic to the sub-continent, face a growing threat from loss of habitat due to human activity, widespread presence of toxins, including pesticides; hunting and trapping for the pet trade. Diminishing population sizes of many birds because of one factor brings them closer to extinction because of the accelerated effects of others, the report warned. For every bird species that was found to be increasing in numbers over the long term, 11 have suffered losses, some catastrophically.

Rare urban sparrows

Of 101 species categorised as being of High Conservation Concern — 59 based on range and abundance and the rest included from high-risk birds on the IUCN (International Union for Conservation of Nature) Red List — endemics such as the Rufous-fronted Prinia, Nilgiri Thrush, Nilgiri Pipit and Indian vulture were confirmed as suffering current decline, and all except 13 had a restricted or highly restricted range, indicating greater vulnerability to man-made threats.

Among widely known species, the common sparrow, long seen as declining in urban spaces, has a stable population overall, although the data from major cities such as Mumbai, Delhi, Kolkata, Bengaluru, Hyderabad and Chennai confirm the view that they have become rare in cities and urban areas. Among the possible reasons for this is a decrease in insect populations as well as nesting places, but there is no conclusive evidence in the scientific literature on radiation from mobile phone towers playing a part.

The SoIB was produced using a base of 867 species, and analysed with the help of data uploaded by birdwatchers to the online platform, eBird. Adequate data on how birds fared over a period of over 25 years (long-term trend) are available only for 261 species. Current annual trends are calculated over a five-year period.

Looking at the health of avifauna based on scientific groupings such as raptors (birds of prey), habitat, diet, migratory status and endemicity (exclusively found in an area), the analysis concludes that raptors overall are in decline, with ‘open country’ species such as the Pallid and Montagu Harriers, White-bellied Sea Eagle and Red-necked Falcon suffering the most.

The severe long-term decline of vultures, recorded and analysed for years now, is underscored by the report.

Migratory shorebirds, along with gulls and terns, seem to have declined the most among waterbirds, the report states, consistent with population trends among Arctic-breeding shorebirds based on independent assessments.

Habitats need help

Forward-looking actions suggested by the report include an update to the Red List of endangered species published by IUCN using the SoIB, collaborative research by scientists and citizens and urgent emphasis on habitats of species of high concern, notably grasslands, scrublands, wetlands and the Western Ghats.

Suhel Quader, a member of the SoIB team, noted that the report was a first step and an assessment of trends rather than causes. “Habitat loss and fragmentation are known causes of species declines, but targeted research is needed to pinpoint causes of decline”, he said.

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