The 2023 State of
India’s Birds Report was released in August 2023. The report is a
periodic assessment of the distribution range, trends in abundance, and
conservation status for most of the bird species that regularly occur in
India. With their ubiquity and ecological importance, birds are
excellent indicators of the state of our natural world and are potent
cultural symbols of nature. As a comprehensive, national-level
assessment, the report points the way towards conservation needs of
India’s birds.
The
report was produced as a partnership between the 13 organisations
including the Bombay Natural History Society, WWF, Wildlife Institute of
India, and Wetlands International.
The report assesses the
status of 942 bird species largely using data uploaded by birdwatchers
to the online platform eBird. The assessments are based on three
indices. Two are indices of change in abundance: Long-term Trend (i.e.,
change over c. 30 years) and Current Annual Trend (i.e., annual change
over the past eight years); the third is a measure of Distribution Range
Size within India.
Key points of the report:
• 30,000+ birdwatchers contributed 30 million observations analysed for trends and distribution.
• 942 Indian birds assessed for conservation priority.
o 178 classified as High Conservation Priority.
o 217 species stable or increasing in the last eight years.
o 14 species, including Indian Roller, recommended for IUCN Red List reassessment.
o Asian Koel has increased in the past three decades.
o Indian Peafowl continues to thrive.
o Raptors, migratory shorebirds, and ducks have declined the most.
o Birds that live in key habitats like open ecosystems, rivers, and coasts have declined.
•
Policy and action must align to highlight species of high conservation
priority, address problems of neglected habitats, and promote research
and monitoring.
Of the total of 942 species, 523 had sufficient
data for estimating Long-term Trends. Among the 523, Long-term Trends
could be determined for 338 species (the remaining 185 had trends
categorised as inconclusive trends). Of these 338 species, 204 have
declined in the long term, 98 show a trend that is indistinguishable
from stable, and 36 have increased.
Using these three indices together with the IUCN global Red List of Threatened Species 2022 (hereinafter ‘IUCN Red List’), species were classified into categories of Conservation Priority for India: 178 as High 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. Species were also
categorised as High Priority species for India, if their current range
is Very Restricted, or if their abundance trend could not be assessed
but they are classified as Globally Threatened in the IUCN Red List.
Threats to birds
The report also listed the following threats to the birds of India:
Monocultures:
Monoculture plantations (or monocultures) include commercial
plantations of coffee, tea, arecanut, cardamom, rubber, teak, or other
species, which are created by large-scale clearance or modification of
natural habitats like forests and grasslands. Commercial monocultures
are known to harbour fewer bird species than natural forests within the
same biome.
Environmental Pollutants: Heavy metals,
pesticides and even veterinary drugs are on top of the list of known
environmental pollutants endangering birds. The evidence implicating
environmental pollutants in the massive decline of vultures is clear.
However, the long-term consequences of other toxic chemicals for birds
are still unclear in the absence of rigorous research that combines
systematic sampling of pollutants in the environment together with
toxicological studies on birds.
Forest Degradation:
Forest degradation is a well-known driver of biodiversity loss. As a
result, specialist bird species, including forest specialists, have
suffered long-term declines. One evident impact is a reduction in
species richness and overall abundance in degraded forest in comparison
with protected forest. Further, species composition also changes, mainly
due to the decline of forest specialists, large-bodied frugivores, and
understorey insectivores.
Urbanisation: Urbanisation has
become a key driver of global land-use change in the past 50 years. As
roads and built-up areas increase, the resulting loss and fragmentation
of natural habitat for birds exposes them to novel stressors such as
elevated pollution levels, increased temperature, and increased density
of free-ranging domestic predators like cats and dogs. Food subsidies in
urban areas can result in the increase of behaviourally dominant
species such as House Crows and feral Rock Pigeons, thereby crowding out
other species. The most urbanized areas have the least number of
species, the least number of rare species, and the fewest insectivorous
species.
Energy Infrastructure (Wind energy and power lines): A wide range of bird species are known to be killed by collisions with wind turbines.
The species most at risk appear to be large-bodied birds, such as
storks, bustards, cranes, vultures, eagles, but other smaller species
suffer collisions too.
Avian Disease: Anthropogenic
drivers such as land-use change, intensive livestock production,
wildlife trade, and climate change are now known to have indirect
effects on the emergence and cross-species transmission of pathogens.
Globally, birds are hosts for an astonishing diversity of parasites such
as Plasmodium, avian influenza virus and West Nile virus. The impact of disease on avian population declines in India is
poorly understood due to a lack of long-term studies. India is
considered a hotspot for endemic vector-borne diseases. Avian influenza
outbreaks in 2020–2021 swept through many Indian States, causing mass
mortality of wild birds.
Illegal Hunting and Trade:
Illegal hunting is the hunting or capture of wild species without legal
sanction. Live birds are trapped for the pet trade, or hunted for their
derivatives such as meat, eggs, feathers, claws, beak, and casque.
Further, superstitious beliefs can lead to the illegal hunting of
species like owls or Indian Roller. Fashion or hobbies can lead to a
demand for feathers for hats, for fly-fishing, and other body parts for
amulets or curios. To tease out the synergistic effects of land-use
change (habitat loss/alteration) and illegal hunting on a bird species
may be difficult and extremely challenging, and hence hard to
generalise. Within India, it is this combined effect that is likely to
be the most critical, as exemplified by the decline of Manipur Bush
Quail and Green Munia.
Climate Change: Shifting baselines caused by climate change make it challenging to diagnose threats to birds. Researchers commonly compare disturbed and undisturbed habitats to infer degree of suitability for birds. However, climate-driven changes in avifauna make modern bird communities
in undisturbed habitats different from historic ones. Without long-term
data, the unknown extent of climate change impact on comparison
benchmarks makes it difficult to assess land-use change effects on
birds.
One way in which climate change affects bird survival and
reproduction is through the disruption of species interactions by
phenological mismatches and range shifts. Mismatches in seasonal timing
(of migration, breeding, emergence) between birds and their prey can
reduce survival and reproduction and also lead to fatal competition with
other species. In parallel, range shifts lead to the loss of overlap
between species in space, and thereby loss of their interactions.
Additionally, new and dangerous interactions might emerge.
Climate
change can also push mountain species directly towards extinction.
Terrestrial bird species diversity is concentrated in tropical
mountains, with each species adapted to a specific temperature range
tied to altitude. The Himalaya and Western Ghats are particularly rich
in bird diversity, with the latter being a hub for bird endemism.
However, climate change poses a threat to high-elevation bird species as
favourable conditions shrink at mountain summits, potentially causing
local extinctions.
