State of birds: Most species show dip, Indian Peafowl among those flourishing

The Peafowl, India’s national bird, is one of the most rapidly increasing species in the country today, it says, “expanding into habitats where it has never occurred previously”.

“In the last 20 years, Indian Peafowl has expanded into the high Himalaya and the rainforests of the Western Ghats. It now occurs in every district in Kerala, a state where it was once extremely rare. Apart from expanding its range, it also appears to be increasing in population density in areas where it occurred earlier,” the report says.

Among the bird species that have been doing well, compared to their pre-2000 baseline, the Asian Koel has shown a rapid increase in abundance of 75%, with an annual current increase of 2.7% per year. So have the House Crow, Rock Pigeon and the Alexandrine Parakeet that has established new populations in several cities.

Released after a gap of three years, the report is an assessment of the distribution range, trends in abundance and conservation status of 942 of India’s 1,200 bird species and has been carried out by 13 partner organisations, including the Wildlife Institute of India (WII) and Zoological Survey of India (ZSI).

The assessments rely on three indices. Two of them are related to change in abundance — long-term trend (change over 30 years) and current annual trend (change over past seven years) — and the third is a measure of distribution range size in India. According to the report, long-term trends as well as current annual trends could not be established for many of the 942 species.

Of the 338 species, for which long-term trends have been identified, it says, 204 or 60% have declined in the long term, 98 species are stable, while 36 have increased. Similarly, current annual trends could be determined for 359 species, of which 142 species or 39% are declining, 64 are in rapid decline, 189 are stable and 28 bird species are increasing.

The International Union for Conservation of Nature (IUCN) Red List of Threatened Species shows that 49% of bird species worldwide are declining in population, compared with only 6% increasing.

The range size, or measurement of a bird species’ territory and home range, was assessed for all 942 bird species. According to the report, the range size of 39% bird species is moderate, 33% is very large while 28% species inhabit a “restricted and very restricted’’ area.

Using IUCN standards, the report says that 178 bird species are high conservation priority, 323 as moderate priority and 441 as low priority. Species of high priority include those whose abundance indices have declined considerably in the long term and continue to decline today.

“It is very difficult to carry out a census on birds. It is not done anywhere in the world. Instead, we look at the ‘abundance’ of the bird species based on sightings. This gives us an indication of the population size as well as its distribution,” says Dr Ghazala Shahabuddin of ATREE, one of the lead authors of the report.

The report found that bird species which are “specialists’’ – restricted to narrow habitats like wetlands, rainforests and grasslands, as opposed to species that can inhabit a wide range of habitats such as plantations and agricultural fields – are rapidly declining.

The “generalist’’ birds that can live in multiple habitat types are doing well as a group, the report says.

“Specialists, however, are more threatened than generalists. Grassland specialists have declined by more than 50%, indicating the importance of protecting and maintaining grassland ecosystems.

A steep decline of birds that live in a wide variety of open habitats in addition to grasslands suggests a need to investigate threats in, for example, open agricultural landscapes and fallow land. Birds that are woodland specialists (forests or plantations) have also declined more than generalists, indicating a need to conserve natural forest habitats so that they provide habitat to specialists,” says the report.

Abundance trends of migratory species show that long-distance migrants, such as migratory birds from Eurasia or the Arctic, have declined the most – by more than 50% – followed by short-distance migrants.

Shorebirds that breed in the Arctic have been particularly affected, declining by close to 80%. By contrast, resident species as a group have remained much more stable.

Dietary requirements of birds have also shown up in abundance trends. Birds that feed on vertebrates and carrion have declined the most, “suggesting that this food resource either contains harmful pollutants’’.

Vultures were nearly driven to extinction by consuming carcasses contaminated with diclofenac. One of the most prolific birds in India, their numbers had dropped to near zero in the 1990s-early 2000s. Raptors are one of the most affected species in the country due to agrochemicals, the report says.

White-rumped Vulture, Indian Vulture, and Red-headed Vulture have suffered the maximum long-term declines (98%, 95%, and 91%, respectively). Today, remnant vulture populations occur in and around Protected Areas.

The report has found that birds that feed on invertebrates, including insects, are declining rapidly, which is in keeping with the worldwide trends of decrease in insect populations. The trend analysis shows that birds that feed on fruits and nectar are doing well.

Birds that are endemic to the Western Ghats and Sri Lanka biodiversity hotspot have rapidly declined in India over the past few decades.

India is home to 232 endemic species, found nowhere else in the world.

In the Western Ghats, most endemics are inhabitants of rainforest, such as White-bellied Treepie and Wayanad Laughingthrush. In particular, the Great Grey Shrike has shown a long-term decline of more than 80%.

Ducks are also rapidly declining in India. India hosts eight resident and 35 migratory species, which occupy a range of habitats, including inland lakes and tanks, submerged paddy fields, rivers, forest pools, and coastal lagoons. Large congregations of ducks occur in Chilika, Pulicat, Rann of Kachchh, Maguri, Loktak, Sambhar, and Keoladeo. The
Baer’s Pochard, Common Pochard, Andaman Teal have been found to be most vulnerable.

Riverine sandbar-nesting birds are also showing a decline due to widespread pressures on rivers from irrigation schemes, transportation, human disturbance, domestic use, and pollution from agricultural and industrial chemicals, variations in the water level and sand mining.

Of the large waterbirds, the Glossy Ibis and Black-headed Ibis have increased dramatically in abundance over the past three decades, by over 130% and 80%, respectively. The Painted Stork and Spot-billed Pelican show a trajectory of increase and then more recent decrease of 2-4% per year to reach historical levels. But the Eurasian
Spoonbill has declined by more than 50% in the long term and by over 6% annually since 2015.
Sarus Crane has rapidly declined over the long term and continues to do so.

Of the 11 species of woodpeckers for which clear long-term trends could be obtained, seven appear stable, two are declining, and two are in rapid decline. The Yellow-crowned Woodpecker, inhabiting widespread thorn and scrub forest, has declined by more than 70% in the past three decades.

While half of all bustards worldwide are threatened, the three species that breed in India – the Great Indian Bustard, the Lesser Florican, and the Bengal Florican – have been found to be most vulnerable.