| The vulture: Dwindling numbers
Once upon a time, not so long ago, there were hundreds of vultures in Calcutta, which soared over the city in flocks that occasionally perched on bridges and treetops. The bird that is considered one of the most critically endangered species in the world has been disappearing fast from the skyline. However, in spite of its appearance on the endangered list several years ago, there has never been a study conducted on them in Calcutta. Until now.
An enthusiastic group of amateur bird watchers, kolkatabirds.com, has finally come up with a study on the white-rumped vulture. With the threat of extinction looming large, the time, they felt, was right to study the majestic scavenger birds in an attempt to increase awareness. The “first-of-its-kind” study, commissioned by Sumit Sen of kolkatabirds.com, mapped the birds’ habits in the city, over a period of four months, from June to September last year.
Initially, data was collected to locate the spots where vultures exist. Once the sites were identified, the birds were monitored on a weekly basis. The aim was to identify and monitor different roosting and feeding sites. Dead and sick vultures were also recorded, and possible threats to them investigated.
Seven roosting spots were found — Monkey Lane, near the Fort William water supply unit; a pocket within National Library; three trees in front of the Police Training School; the Victoria Memorial grounds; five trees on the St Paul’s Cathedral grounds; four trees near Rotary Sadan; and the Botanical Garden. Of the 18 study days, no vultures were reported from at least one study site on 12 days. The maximum daily count was 92.
The study, released last month, shows that the vultures, although present in Calcutta during the monsoon, disperse to other places towards winter, their breeding season. Nesting vultures are very few in the city, and nesting or incubating vultures are frequently mobbed by kites and crows.
While St Paul’s Cathedral was a favourite roosting ground, the Maidan was a preferred soaring area, and a busy feeding place was near the EM Bypass, close to Ruby General Hospital.
The problem of declining numbers in Calcutta, explains Sen, is the loss of tall trees, the primary nesting location for the birds. At the roosting sites observed during the study period, the vultures used mature debdaru trees that provide a greater height than most other trees in Calcutta. The average height of a roosting branch was about 29.5 ft.
Despite the data collected, there is no previous information available to compare with, he says. “I remember earlier being able to see many more birds around, often a single flock of 100 sitting on Majherhat bridge. Now, all that’s left here is probably about a total of hundred. We had wanted to do another study this year, which is why we held back the report, so that we could compare the results from the two years, but we had no funds,” he adds. “Ecologically, the dwindling population is not a disaster for Calcutta, as such, but the city can support a large vulture population. They’re dying out for various reasons, which is very sad and a loss for us,” Sen signs off.