The city's lakes, which used to harbour a large number of birds, have seen drastic changes.

Hopping from one lake to another, a vigilant eye skywards and on trees, the citizen-driven waterfowl census was conducted over the weekend, marking the first of its kind in the city in this millennium.

The small step, taken by students and avid birdwatchers, covered lakes on Hosur Road and Sarjapur Road. The waterfowl census is being conducted in the city for the first time in nearly 19 years, and the enormous changes in the city’s waterbodies are apparent.

“Land-use has been one of the biggest changes, and all of this has affected the bird population tremendously, particularly among waders,” said Ulhas P. Anand, an avid birder.

While these lakes harboured more than 200 ducks in the past, the number has come down to barely a handful in each lake. “Less than 50 shorebirds were spotted in lakes off Sarjapur Road. This is a worrying sign,” he said.

Garganeys and pintails, which numbered more than 8,000 in the city, have seen the most-drastic falls in population, said birder M.B. Krishna. Similarly, the wader species, sandpiper, was barely spotted.

Apart from Kaikondrahalli lake and Saul Kere, and Madiwala lake to an extent, where 81 spot-billed pelicans were seen, there was little life seen in lakes. In fact, the birders said, many lakes, such as Bhoganahalli lake, have sewage inflow and debris lining the shores; while, lakes such as Gunjur and Gunjurpalya lakes have turned bone dry even after copious rain this year.

Sheshadri, a wildlife expert studying in Singapore, believes leaks from sewage treatment plants, and cutting of trees had contributed to a huge loss. One island with a small clump of trees in the middle of Kaikondrahalli lake harboured more than 300 cattle egrets — a sight that was not seen in many denuded lakes, he said.

Allowing commercial fishing has also affected the bird population, with the census showing only a few birds in areas where nets are sprawled.

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Worse news ahead?

With barely a few lakes boasting thriving bird population, the continuation of the census across the city could lead to worse news.

Birders note that many of the lakes that were once hubs of breeding birds have now turned bone dry. For instance, the Ramapura tank had two decades ago seen over 4,000 ducks; while the nearby Yelamallappa Shetty tank is now bifurcated by the Old Madras road and surrounded by industrial areas.

Similarly, the large Hennagara lake and Jigani lake near Anekal are now barren land. The census in the late 1980s and the mid-1990s had seen several tanks holding a bird population of more than 5,000.

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Why the census?

From reports by Indian Institute of Science (IISc.) researchers on wetlands to the Justice N.K. Patil report on lakes protection, the need for continuous monitoring of bird population in the city’s waterbodies has been one of the critical recommendations.

However, after a series of winter surveys between 1987 and 1996, the waterfowl census, conducted by the Bird Watcher’s Field Club of Bangalore and the State government, wound up.

Ulhas P. Anand, birder, who had participated in the series of censuses, said the withdrawing of government support had seen the census take a long hiatus. “The Department of Forests had supported us in the initial censuses by providing transportation and access. The reports would be submitted to the Asian Wetland Bureau. However, the support stopped and soon even access stopped,” he said.

Birds, after all, are among the best indicator species for the health of a lake. Sewage inflow, cutting of trees, and disappearance of wetlands have a direct impact on their population — something that is being observed disconcertingly in the 2015 waterfowl census.

“Birds are a great indicator species to measure the health of the lake. There is neglect and apathy in many lakes, where sedimentation tanks storing sewage has leaked,” said Sheshadri, a wildlife expert.

Initial observations

Lakes surveyed: 20 on Sarjapur Road and Hosur Road

Only two lakes found with a thriving bird population

Good signs

Kaikondrahalli lake has more than 500 cattle egrets

Madiwala lake has seen 81 spot-billed pelicans

Terrible signs

Less than 50 waders (ducks, sandpipers, stints and stilts) found in these lakes

In 1996, over 50,000 ducks were seen only in Bellandur lake

Access to many lakes gone; lakes on the outskirts bone dry

Just 12 black-winged stilts spotted; compared to flocks of over 100 in the previous census

No garganey and pintail birds seen; their number used to be more than 8,000 in the mid-90s.

Birds in the city

55 species commonly found in the city have been estimated to have declined by 90 per cent

Birdwatchers have recorded at least 316 different species of birds (migratory and local) since 1975 in the city

Shallow water species in threat, while population of larger deepwater species going up owing to poor lake design

Birdwatchers have suggested 115 fruiting and nectar tree species that can be planted in gardens across the city to increase bird population