Birds may
fly no more

By Radhakrishna Rao

FOR many years now, bird-watchers and ornithologists are concerned about the rapidly dwindling number of migratory birds coming from far-off places to India. After a gap of three years, a couple of Siberian cranes have been sighted in the beautiful Keoladeo Ghara National Park in Bharatpur once a well known wintering ground of Siberian cranes.

Crane-lovers say, ecological changes in and around Ghana National Park, as well as the migratory routes of cranes across mountainous regions of China, Afghanistan and Pakistan have resulted in the dwindling number of Siberian cranes visiting India. In parts of Pakistan and Afghanistan Siberian cranes are being trapped and killed by nomadic tribals.

The South Indian "Garden City" of Bangalore was not long back one of the largest wintering grounds of migratory birds. Unchecked air pollution and elimination of tanks and water bodies in the city have conspired to turn Bangalore into an unfavourable destination for migratory birds. Most lakes are being converted into a "real estate goldmine" and the remaining lakes are facing degradation due to infestation of water hyascinth. So most birds have started skipping Bangalore. Says an avid bird-watcher of the city, "It is like watching a dance of death. This morning I stood with my binoculars near the Forest Department’s nursery at the edge of the Madivala tank and spotted a blue kingfisher. I saw it dive into a tangle of water hyacinth. As I trained my sight, I saw it struggling to fly free."

A variety of water fowls, babblers, red-headed merlin, gobblers and flycatchers were a regular visitors to this city with a salubrious climate. In fact, these birds were attracted by the multitudes of insects that thrived in the mango groves in the city. These mango groves have been felled to make way for settlement colonies.

From a small-time town occupying just 60 sq. km, Bangalore has now blossomed into a megacity covering an area of 400 sq km and this unprecedented growth accompanied by the destruction of greenery has resulted in the city becoming a far from ideal haunt for migratory birds.

At the famous Ranganathittu bird sanctuary, located about 15 km from Mysore, pollution of the river Cauvery by industrial effluents and pesticides residues is adversely affecting this avian paradise famous for its water fowls, spoon-bills, pelicans and painted storks. Similarly in the nearby Kokarebelluru the number of pelicans has come down to 300 from an all time high of 2000.

The Chilka lake in Orissa occupying an area of 1165 sq km and considered as Asia’s largest brackish water lagoon, attracts the world’s largest number of birds after lake Victoria in Africa. Among the avian varieties attracted to this lake covered by mangrove forests and known for its pleasant weather are flamingoes, grey pelican, pintails, mallards, black-headed storks and bar-headed shovellers. However, the dwindling number of feathery visitors to Chilka lake is attributed to the deteriorating conditions in and around the lake.

According to the ornithologist U.N. Das, large scale trapping of winged visitors by villagers and reckless expansion of prawn farming have turned Chilka into an unfavourable wintering ground for birds. Every year due to the indiscriminate deforestation in the catchment area of the lake, 13-million tonnes of silt are being deposited into the lake. According to a local farmer, Sushant Da, overexploitation of Chilka has contributed to the upsetting of the eco balance of this tranquil lake and the scarcity of food in the lake area has driven birds away to the paddy fields in the nearby village. Here many of the birds are caught alive by trappers waiting patiently for the avian varieties.

Widespread deforestation, aggravated by indiscriminate logging is known to exert an adverse impact on the migratory movement of birds — occasionally forcing them to change their habitat for survival. Tree felling invariably affects the nesting patterns of birds. "Some species which do it get adapted get affected by the ecological changes taking place, leading to a decline in their population while making room for other species", says Vivek Menon of the World Conservation Union. For instance, he says, while the grey hornbill adapted and survived, the great Indian hornbill could not. "Behavioural changes are passed on from generation to generation. In successive generations young ones develop traits which allow them to survive", says Menon.

Prachi Mehta, a researcher at the Dehra Dun based Wildlife Institute of India has done extensive studies on the consequences of logging in the forests of Satpura ranges in Central India. She point out that generally their population of birds declines at the time of logging. Several species come back after a period of one or two years as logging is done under prescribed conditions and the principle is very selective. "The density of population of yellow-legged pigeon and golden backed woodpeckers was almost zero at the time of logging. But they came back after a year", says Mehta.

Another leading ornithologist, Bikram Grewal says, "besides logging, drainage and pollution too are responsible for the decline of the population of birds such as the hornbill." Grewal says, "this is vicious cycle. If the birds don’t have enough nesting place their frequency will decline. You have to have trees to help birds to propagate."

Interestingly, the ecologically blighted Kashmir valley has become a favourite with the winged visitors. According to recent reports, birds are now returning to the picturesque Kashmir valley in a big way. For instance this year more than one lakh birds from North Europe, Siberia, China and Central Asia migrated to the Hohera wetland reserve, about 10 km to the west of Srinagar. Ornithologists attribute this unusal bird concentration during the current year to the new management inputs like regulation of the optimum water level, controlled and sustainable exploitation of fish, grass and plant resources and added protection provided to the habitat.