Pesticides Spell Doom for bird life in Wayanad By
R Madhavan Nair (Appeared
in THE HINDU, dated 01 April 2003) Many
bird species that once livened up Wayanad's landscape with their
brightly coloured presence and tuneful cries are headed for extinction.
Wayanad district, lying along 'the Western Ghats, is one of the endemic
bird areas (EBA) in the country and is home to nearly 300 species.
Warnings about threats to bird population
have been made
earlier also. But the threat to birds seems to have risen to 'an
alarming level-due to indiscriminate use
of pesticides,
habitat destruction, habitat fragmentation and high levels of deforestation. This
view is endorsed by Vishnudas, a naturalist who has been studying bird
life in Wayanad for nearly 15 years. Till the beginning of the 1980s,
Wayanad with its vast stretches of paddies and rich homesteads, was a
paradise for rich avifauna, including many rare and endemic birds. The
invasion of banana and arecanut into paddy fields and the shift in
agriculture practices torn subsistence cropping to cash cropping and
intensive application of chemical fertilizers and pesticides have caused
irreparable damage to Wayanad's fragile eco-system and has caused
unfavourable living
conditions for birds. Wayanad was almost an ideal habitat for many water birds. But
the ‘heronries’ (nests
of herons), which were once common in the swampy areas of the district,
have been
reduced to
a few sites. The whistling teals, one of the resident ducks, were
once common in paddy fields but are now
seen only in inland lakes of sanctuaries and a couple of sites
near to reservoirs. The
large population of pond herons, considered true indicators of
unpolluted paddy fields, has shrunk to an alarmingly low level in the
past few years. The ruddy crakes once common
along grass
thickets and
swamps, has almost
disappeared. The white-breasted water hen is struggling for survival.
Water birds are the worst affected by the large-scale pesticide
application and change in land use patterns. Use of pesticides
containing heavy
.elements like
cadmium and mercury
in paddy fields led to accumulation of the harmful substances in the
body of the birds through the intake of
small fishes
and shells.
In
birds in the higher levels of the food chain, like raptors, owls and
egrets, it causes abnormalities like laying of shell-less eggs or
sometimes eggs having very thin shells which cannot be incubated by
birds. This in turn affects the reproductive capacity of the birds. It
has been found that the application of thimlet, a pesticide used in
paddy fields, has resulted
even in weakening of flying ability of egrets. This was noticed
in Kaniyambetta panchayath
in 1997. It was
found that the birds that fed in the fields after the application
of the pesticide
were unable to raise their wings and died a slow death within a period
of three days. Similar incidents were
reported from some
other parts of the country also. Owls
are among the worst affected among the land birds. These are now seen
only in a few places. The large brown fish owl, once common among
homestead lands, and cultivations, has almost completely disappeared
from here. The
collard scops owls also have become very rare. The fearsome calls of the
mottled wood owl (popularly known as 'kalan kozhi') are rarely heard. The decline in
owl population is mainly due to large-scale felling of trees, which
support their nesting activities. Owls
usually make nests in tree holes. Big trees and food within easily reach
are needed for breeding. Eucalyptus, acacia and silver oaks, which have
replaced big forest trees, are .not suited to nesting for many birds. The
change from cash crops to pepper plantations has made life difficult for
birds. Though species like barbets are getting adapted to the new
situation, many other species like fairy blue. birds, yellow browed
bulbuls, iora and woodpeckers find
it difficult to survive. Building of nests
in open spaces increases chances of predation by large birds. Dried
trees kept in farms used to be good feeding ground for woodpeckers
and barbets. But very few farmers keep dried trees these days. The Baya
weaver birds, locally called 'thookanam kuruvi', famous for their
delightful hanging nests, have also almost totally
disappeared. The
remaining birds are also facing food scarcity because of
shrinking of paddies. Cutting
down of tall trees has had an adverse effect on rare species like wood
pigeons and emerald doves,
Nilgiri wood pigeon, an endemic and most endangered bird of the
Western Ghats, is almost extinct.
The mountain imperial pigeon, found in thick, forests having tall
trees, is also headed for extinction. The population of house sparrows
was also dwindling fast, according to field studies conducted by Mr
Vishnudas. This might be due to urbanisation and intake of pesticide
coated grains. The
Western Ghats possesses16 endemic bird species and most of them are seen
in Wayanad. Mr Vishnudas believes the current pace of destruction of
habitats would lead to the extinction of not only the endemic species
like the Wayanad laughing thrush, the white-bellied blue flycatcher, the
Malabar grey hornbill, small sunbird, Nilgiri pipit but also other birds
commonly seen in Wayanad. Birds
are ecologically important as they help in maintaining the delicate
balance of rhythms and cycles of Nature by playing the role of seed
disbursers, insect controllers and pollinators. Mr. Vishnudas, a
research associate with the Rural Agency for
Social and
Technological Advancement (Rasta), points out that not enough
attention was being paid to the conservation of birds and their
habitats. One
effective way of conserving bird population is for people in cities and
villages to provide birds nesting sites. Suitable trees have
to be planted in
homesteads and these
trees and shrubs left untouched during the breeding season. Very little
attention is paid to such measures that can help birds survive the
steadily rising threats to their habitats. |