New Delhi: A sizeable proportion of Indian bird species, especially carnivores, insectivores, or granivores are “declining more rapidly than omnivores and nectar eaters, indicating the impact of diet on the avian population.
According to the second edition of State of India’s Birds Report 2023 released recently assessed 942 bird species across the country birds that feed on fruits and nectar are doing well, because these resources are readily available even in heavily modified rural and urban landscapes.
"Bird populations are therefore not just influenced by direct threats to their habitats, but also by the availability of food resources," the report notes.
The report has been published by a group of 13 government and non-government institutions, including the Bombay Natural History Society (BNHS), Wildlife Institute of India (WII), and Zoological Survey of India (ZSI).
The report is based on data provided by 30,000 birdwatchers across the country.
It notes that birds in India that feed on vertebrates and carrion have declined the most, suggesting that this food resource either contains harmful pollutants or is declining in availability, or both. Some carnivorous birds are falcons, vultures, shikras and black kites.
Moreover, birds that feed on invertebrates (including insects) like the Indian roller are declining rapidly. Recent findings show that insect populations worldwide have reduced and that pesticides are thought to be a main contributor to massive declines in European insectivorous birds.
"A decline in insects, for example, could affect insectivorous birds. Mice in agricultural landscapes are food for several raptors, but these mice may carry pesticides and other agrochemicals that may be harmful for the birds that eat them," the report shows. Vultures were nearly driven to extinction by consuming carcasses contaminated with diclofenac.
"The trend analysis shows that birds that feed on fruits and nectar are doing well, maybe because these resources are readily available even in heavy-modified rural and urban landscapes. The continued availability of these resources even outside natural ecosystems can sustain this encouraging story," the report reveals. The report published last week assessed the status of 942 bird species, largely using data uploaded by birdwatchers to the online platform eBird.
In 2020, India joined the list of countries that regularly assess the status of their birds, with the launch of the first report on the State of India’s Birds (SoIB) at the Conference of Parties to the Convention on Migratory Species in Gandhinagar.
The assessments are based on three indices. Two are indices of change in abundance: The long-term Trend (change over around 30 years) and the current annual trend (annual change over the past eight years); the third is a measure of Distribution Range Size within India.
Using these three indices together with the IUCN global Red List of Threatened Species 2022 (hereinafter ‘IUCN Red List’), species were classified of Conservation Priority for India: 178 as High Priority, 323 as Moderate Priority and 441 as Low Priority.
In all countries where bird populations have been monitored and assessed, birds in India are faring poorly overall, the report states.
A few generalist species are doing well, notable among them being feral Rock Pigeon, Ashy Prinia, and Indian Peafowl. Other familiar species, including Baya Weaver and Pied Bushchat, are relatively stable. But the larger picture is grim as 60 per cent of species show long-term declines (out of 348 species that could be assessed for Long-term Trend), and 40 per cent of species are declining currently (out of 359 species assessed for the current annual trend).
"The declines are not spread uniformly across different types of species; examining differences across groups of species that share common characteristics reveal informative patterns Habitat specialists—particularly specialists of grasslands and other open habitats, wetlands, and woodlands—are declining rapidly," the analysis notes.
The report mentions that migratory species appear to be under greater threat than non-migrants. And 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 informs. The report mentioned that equally worrying is that a considerable number of species lack the data to be assessed. "Insufficiency of data meant that of the 942 species covered in this report, Long-term Trend could not be calculated for 44 per cent and Current Annual Trend could not be estimated for 31 per cent of the species," the report notes. —ANI
