Pollution: Fewer feathered guests arrive this year (Hindustan Times 02 February 2012)

The high pollution level in the Yamuna, continuous destruction of natural habitat and inconsistent winter have made many migratory birds — 21 of the 27 major species —skip the city this year.
Endangered species like painted storks, black-headed ibis and ferruginous pochards have come in few numbers, says the Asian Water birds Census (AWC).
Of the various stretches of the Yamuna between Wazirabad barrage and the point where it leaves the Capital, the Okhla Bird Sanctuary has fared better with 58 of the 75 local and migratory species being sighted there.
Those who did not show up include temminck’s stint, Indian cormorant, greater flamingo and great white pelican. Also, the numbers of several species of ducks and storks – bar-headed geese, northern shoveler, northern pintail and red-wattled lapwing – have witnessed a sharp decline at Okhla, the census said. From the other stretches of Yamuna, the species that have missed the city include red-crested pochard, common coot, spot-billed duck and little cormorant.
Besides water pollution and loss of habitat, the inconsistent winter has played a spoilsport, said TK Roy, conservationist and AWC Delhi state coordinator. “Usually, birds start arriving in the city by October-end or the beginning of November. This time in 2011, Delhi lacked the chill, so many species flew past the area,” he said.
Sajit P Mohanan of Delhi Birds Group said it is not exactly that birds are “missing” but certain species may have chosen some other locations. For instance, construction activity along Dwarka Expressway has affected the arrival of birds at Najafgarh jheel.
Manoj Mishra of Yamuna Jiye Abhiyan said some birds survive in polluted water, but many need clear water and these species avoid polluted stretches. “With polluted stretches, we find that the diversity of bird life comes down drastically. The difference can be seen at the Yamuna Biodiversity Park and upstream of Wazirabad compared with areas downstream of it,” he said.