The number of vulture nests built during the breeding season in the Mudumalai Tiger Reserve has dropped drastically, from 47 active nests in 2018 to just over 30 this year.
The findings were made during a joint exercise by the Forest Departments of the Mudumalai Tiger Reserve (MTR) and Sathyamangalam Tiger Reserve (STR) to estimate the vulture population in the Sigur plateau, and to ascertain whether the breeding season for the critically endangered species of birds has been successful.
Speaking to The Hindu , A. Pushpakaran, Deputy Director of MTR (buffer zone), said that field staff had identified around 32 active nests in the Sigur forest range during the two-day-long exercise. “What is concerning is that all these nests are located in a concentrated cluster in an area called Jagulikadavu in the Nilgiris North Eastern Slope,” said Mr. Pushpakaran, who said that the number of vulture nests in the other sites where vultures usually nested in the previous years had dropped dramatically in 2019.
“We still don’t understand the reason for the dramatic decrease in the number of nests,” admitted Mr. Pushpakaran, who said that forest staff had recorded the presence of nests of the White-rumped vulture, long-billed vulture and the Egyptian vulture during the exercise. However, the nest of the extremely elusive Asian king vulture had still not been recorded, said officials.
“One explanation for the decrease in the number of nests may be because of invasive weeds taking over large parts of the MTR buffer zone as well,” said Mr. Pushpakaran, who said that the birds required wide open spaces to take off and land when scavenging for food. As a result of invasive weeds taking over, scavenging on leftover remains left behind by carnivores may no longer be an option for the animals, forcing them to move to other locations in search for food, officials said.
B. Ramakrishnan, assistant professor at the department of wildlife biology at the Government Arts College in Udhagamandalam, who has outlined strategies that need to be adopted to secure the vulture populations in Southern India, corroborated the Forest Department’s findings, stating that in Anaikatty, where usually there were between 9-12 nests during the breeding season, only a single nest was recorded this year, while in Ebbanadu, where anywhere between 12-18 nests are usually found, only six were identified in 2019.
“One scientific reason for the decrease in the number of nests could be due to the effects of the drought which affected the Nilgiris in 2017,” said Mr. Ramakrishnan, who said that one of the vultures’ prime sources of food – cattle, being raised by villagers in the fringes of the tiger reserve, had seen an almost 50-75 % drop in their population.
“Cattle are easy targets for carnivores, and we have seen around 60 heads of cattle being preyed on by carnivores over the last 5-6 years. Due to the drought in 2017, many cattle died, or were sold off by farmers in the tiger reserve, greatly diminishing prey not just for tigers, but also scavenging opportunities for vultures,” said Mr. Ramakrishnan.
Mr. Ramakrishnan said that recent studies showed that food availability had a direct correlation with the success of vultures’ breeding season. “It is also premature to assume that there is a decrease in the population,” said Mr. Ramakrishnan, stating that the vultures could have moved and set up nests in other areas in the Sigur plateau – in Bandipur, Nagarhole and Muthanga Wildlife Sanctuary. “This is why a synchronous monitoring exercise, carried out in Tamil Nadu, Kerala and Karnataka, to estimate the number of nests in a breeding season across the landscape was of paramount importance,” he added.
