The Yellow-throated ‘bulbul’ of the Eastern Ghats4 min read . Updated: 28 Jul 2017, 04:06 PM IST
How scientists are trying to find out more about this rare songbird through genetic studies
In one of the laboratories at the Centre for Cellular and Molecular Biology—Laboratory for the Conservation of Endangered Species (CCMB-LaCONES), Hyderabad—hangs a whiteboard where research students have drawn a clock-face circle and marked the points with doodles depicting their research topics: a salamander, a pile of faeces (yes you read it right—understanding wildlife diet through faecal matter), a toad and a bird.
The bird turned out to be unique—the Yellow-throated Bulbul, endemic to the Eastern Ghats of peninsular India. “This is an ancient bulbul, with preliminary studies pointing towards a unique evolutionary history, but unfortunately the species is threatened with extinction due to habitat loss," says Karthikeyan Vasudevan, senior principal scientist, LaCONES. Since 2015, Vasudevan’s student Ashish Jha has been trying to find out more about the songbird through genetic studies but getting permissions from the forest departments of different states has been an uphill task.
The crestless yellowish-green and grey Yellow-throated Bulbul is found in small patches (and in small numbers) in south India, especially in rocky scrub forests. “The northernmost population of the species is in Achampet (Telangana), the southernmost population is in the Grizzled Wildlife Sanctuary (Tamil Nadu), the westernmost population is in Hampi (Karnataka), while the easternmost population is in Gingee hills (Tamil Nadu)," says Jha. T.C. Jerdon, a British naturalist, first described it in 1844 from Horsley Hills, Chittoor (Andhra Pradesh).
Vasudevan takes me on a birdwatching trip to get a look at its habitat. A 2-hour drive from Hyderabad takes us to the edge of the Amrabad Tiger Reserve, the Nallamala Hills, where Vasudevan and his team have been monitoring a small population of Yellow-throated Bulbuls.
On the edge of the reserve, the Umamaheshwaram temple complex nestled on the rocky cliff edge is a well-known pilgrimage site. There, under the giant canopy of a fig tree which has branched out from a narrow crevice, we found our bird. Through binoculars, we watched it play hide-and-seek in the canopy. Then it darted inside the temple portico in search of insects. Pointing to the numerous crevices in the cliffs above, from where water trickles down, Vasudevan says the bulbul uses these spaces for nest-building—it is the only bulbul known to breed in rock cliffs.
My interest prompts him to ask, “How many birds (Yellow-throated Bulbuls) do you think there are in this habitat?" The consensus was 20. Unlike the other feisty bulbuls, which move in flocks, this shy species is often seen in pairs.
For the past couple of years, Vasudevan and his team have been trying to gather blood samples from the known populations in different places—approximately 10 microlitres (about one-third of a drop from a dropper) for DNA analysis and phylogenetic studies. This will reveal, apart from population estimates, the entire biogeography of the species, the reason for endemism, and whether there are any parasites in the blood or diseases. They use mist netting to trap the birds.
“The preliminary phylogeny of Indian bulbuls reveals that the Yellow-throated Bulbul does not have a sister species and has a unique evolutionary history," says Jha. The team has managed to get seven samples so far and is looking for more in Tamil Nadu and Karnataka.
“Our ongoing research shows that less than 100 separate populations of the Yellow-throated Bulbul remain in less than 1,000 sq. km of suitable habitat across peninsular India, the bird’s geographical range," says Vasudevan. “In-depth genetic study of individual bulbul populations will reveal if they are interconnected (signifying the ability of the bird to fly to new habitats) or inbred. It can reveal if these small populations are the result of shrinkage of habitat or one population that has dispersed and occupied suitable habitats around," adds Jha.
Vasudevan wants this endangered bulbul to be declared the flagship species of the Eastern Ghats, which has been largely overshadowed by the biodiversity-rich Western Ghats and mined extensively, especially by the construction industry. This has eaten into a large chunk of the bulbul’s habitat. According to research data from BirdLife International, a global non- governmental organization, the species has disappeared from six sites in Karnataka—Thondebhavi, Bananthimari, Shivanahalli, Devanahalli, Chinthamani and Sadahalli. News reports suggest that a portion of the Amrabad reserve could be denotified for uranium mining. There are, apart from the bulbul, at least six other threatened and endemic species in the Eastern Ghats.
“What is needed is preventive conservation; an idea to adopt conservation measures for a species before its population crashes to become ecologically defunct (like the Great Indian Bustard, with just around 100 individuals surviving) and its conservation prospects, gloomy," says Vasudevan.
In effect, by focusing on certain categories in the International Union for Conservation of Nature’s Red List of Threatened Species, wildlife conservationists are ignoring vulnerable species like this bulbul. “Categories such as ‘endangered’ and ‘critically endangered’ in the Red List prompt certain action, those that are ‘near threatened’ or ‘vulnerable’ do not evoke any response. Unfortunately, these are the species that are going to move into the next higher level of endangerment," says Vasudevan.
The team at LaCONES hopes that work on the Yellow-throated Bulbul will also help preserve scrub habitat across the Eastern Ghats and promote the concept of preventive conservation for similar species.
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