Just as with most residents looking to stay in the city, the populations of avian species seems to be moving away from the crowded city centre and into the outskirts.
With the city replacing its green cover with concrete and the lakes filling up with sewage instead of clear water, birds that had enthralled watchers within the city are becoming a rarer sight. Birdwatchers have estimated declines of around 80-90 per cent in species that used to be commonly sighted in Bengaluru.
“Imagine, in Belandur, we could find more than 25,000 ducks in the 90s. One clap and the whole flock would nearly blackout the sun. Now, all you can see is froth,” says Ullas Anand, who has been a birdwatcher here for 28 years. The group organises walks every Sunday, and through the years the number of migratory and breeding birds have drastically fallen.
Similarly, birder M.B. Krishna says species such as Copper-Smith Barbet, once seen in hundreds in Lalbagh, have declined by at least 98 per cent. Rapid commercialisation has wiped off almost all the birds seen in Jayanagar, Basavanagudi and Malleswaram, which were once birding hotspots.
Lakes and birds
It isn’t just green cover that is affecting the avian population. Renowned city birdwatcher S. Subramanya – who estimates that at least 110 species of birds once thrived in the tank eco-system of the city – said the dying lakes had changed the dynamics of the bird population.
“The encouraging of commercial fishing has seen the introduction of invasive species of fish. This has seen an increase in populations of larger birds which were rare such as Spot-billed Pelican (from 15 to more than 300 in some lakes) and the Large Cormorant, at the expense of the Little Cormorant,” he said.
Moreover, the nature of tanks themselves has changed. A few decades ago, the lakes were non-perennial, and in the summer seasons became mushy wetlands that aided the bird population. Now, the incessant flow of sewage has made the lakes perennial, while the tank beds have been coated with thick sludge, preventing any natural submerged vegetation from growing, he said.
The result is that a large number of breeding and migratory birds now chose to nest besides the lakes of Yelahanka or in the forests near Kanakapura Road.
Designing lakes for birds
Can lakes be developed better to accommodate the large diversity of avian species that used to make the city home?
Ornithologist Subramanya S., a senior professor at the University of Agricultural Sciences, believes the current system of “development” of lakes has not taken into account the large number of species that thrive in shallow waters.
“Naturally the lakes slope to a deep end. This allows for one end to be shallow, where aquatic vegetation can grow. Instead, lake developers are removing silt in a soup bowl design, while the shore is embanked. This design excludes shallow water and shore birds,” he said.
Among the success stories of integrating the knowledge of bird populations into lake design is Puttenahalli lake in Yelahanka. Similarly, Amblipura and Kaikondanahalli lakes emphasise a shallow water eco-system, resulting in a resurgence of birds.
Birds are among the best visible indicators of the health of the lake, he said. “Hebbal lake used to have many Pied Kingfishers. But, as the lake got more murky, these birds were spotted in fewer numbers. That is because they need clear water to see the fish they are hunting,” said Prof. Subramanya.
Birding reaches new heights in the city
Despite fewer spots available to spot birds, bird watching is on the rise in the city. Birdwatcher S. Subramanya says the number of those interested in the hobby has gone up from 30 in the mid-1970s to more than 2,700 now. “The internet has changed the way we look at birds. If we had this sort of interest and numbers when we started four decades ago, we could have still protected the lakes and birds,” he said.
Ulhas Anand, who has been birdwatching for nearly three decades, said the increase in interest coincided with the explosion of those using cameras to shoot the flora and fauna in the city. “Wildlife is now being viewed through the lens. They also want to know more of the species they find, and many contribute genuinely to the birdwatching community,” he said.
Falling numbers
- 55 species commonly found in the city are estimated to have declined by 90 p.c.
- 316 different species (migratory and local) spotted since 1975 in city
- Shallow water species in threat, while larger-deep water species going up due to poor lake design
What can be done:
Birdwatchers have suggested 115 fruiting and nectar tree species that can be planted to increase bird population
Threats of lake ‘development’:
‘Developed’ Hebbal lake: 18 species, 327 birds
‘Undeveloped’ Singanayakahalli lake: 32 species, 2,157 birds
Birds that have become rarer in the city centre:
Pheasant-tailed Jacana, Leafbird, Booted Eagle, Red-necked Falcon, Egyptian Vulture, Garganey, Blue-winged Teal, Northern Pintail, Northern Shoveler, Oriental White-eye, Red Vented Bulbul, House Sparrow, Purple Sunbird
Current birding hotspots*:
- Hessarghata Lake: 217 species
- Valley School, Kanakapura Road: 178 species
- Jakkur Lake: 140 species
- Kaikondrahalli lake, Sarjapur Road: 123 species; 43 residing in the lake
- Indian Institute of Science: 111 species
- Puttenahalli Lake, Yelahanka: 84 species of birds
- Lalbagh: 95 species
Source: birdwatchers; *ebird.org
