Lights that were earlier switched off by 7 p.m. now stay on until 9 p.m., after the installation of the centrally-monitored lighting through CCMS smart meters at the lakes. Kere Mitras and NGOs working on lakes say applying the same timing to lakes ignores ecological function, particularly in the evening when large numbers of birds return to sleep.
The concern is particularly worrisome at Dorekere lake, where birds arrive in large numbers in the evening and settle on the island and surrounding trees for the night. A biodiversity study by ActionAid, in association with the Australian Consulate General, Bengaluru, recorded 63 resident species and 11 migratory species at the lake between July 2023 and May 2024.
The lighting, volunteers say, makes the lake less attractive as a roost because birds use the onset of darkness as a cue to settle down for the night. Keeping the area brightly lit for another two hours can keep birds active, particularly when the lights fall directly on the trees or the island where they roost. Birds may then eventually move to darker parts of the lake or look for another roost altogether.
Raghavendra B. Pachhapur of ActionAid said the lighting schedule earlier allowed the lake to become dark relatively soon after dusk. He argued that it was not about preventing residents from using the lakes in the evening, but about treating a lake ecosystem in the same way as a conventional public space.
Dorekere’s bird records show that the lake is not simply a place where birds just pass through. Species such as Glossy Ibis, Cattle Egret, and Black-headed Ibis have been observed using the island to roost during the non-breeding season, even though they have not been recorded breeding there. The Glossy Ibis numbers increase significantly around mid-October, with up to 620 birds recorded roosting on the island.
At Doddakalasandra too, ActionAid’s recent survey recorded 46 bird species in a single day during March this year. Volunteers like Soundararajan Rajagopalan, a Kere Mitra for Doddakalasandra lake, pointed out that migratory birds visit Bengaluru between October and March, and the lake attracts both water-dependent and tree-dependent species.
The impact of artificial lighting is not limited to birds choosing a different tree for the night. A roost is part of a larger habitat, and repeated disturbance can change how birds use a lake over time, he said. “If you continue to do that, it disturbs birds and they will not consider this as a home and it has to switch places,” Mr. Rajagopalan said, adding that with this small change, we are pushing birds again to go outskirts.
GBA officials, however, said that the lights were set on an auto-timer till 9 p.m. to avoid any kind of illegal activity and to make the public feel safe as the lakes are usually open till 7.30 p.m. to 8 p.m., depending on the location.