The Hindu : Pesticides spell doom for bird life in Wayanad

Online edition of India's National Newspaper
Tuesday, Apr 01, 2003

Southern States

Southern States - Kerala

Pesticides spell doom for bird life in Wayanad

By R. Madhavan Nair

KOZHIKODE MARCH 31. 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 level 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 from subsistence cropping to cash cropping and intensive application of chemical fertilizers and pesticides have caused irreparable damage to Wayanad's natural eco-system and created 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 crake, 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 has led to accumulation of these 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 thimet, a pesticide used in paddy fields, has resulted even in weakening of flying ability of egrettes. This was noticed in Kaniyambetta panchayat 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 there.

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, ayora and woodpeckers find it difficult to survive. Building nests in open spaces increases chances of predation by large birds.

Dried trees kept in farms for firewood 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. The 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 possesses 16 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.

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