Monday, October 31, 2011

Malabar ornithological survey: Kerala sets new benchmark

Red-whiskered bulbul. Photo: C.K. Vishnudas and E.M. Manoj
The Forest Department of Kerala has just completed the first-ever ornithological survey for the Malabar region recording 341 species of birds.
The survey is one of a kind notable for its sheer depth and span, more comprehensive than all such surveys undertaken so far in India. Hopefully, the five-member team including four eminent ornithologists commissioned by the Forest Department of Kerala, having completed such a through status report on the birds of Kerala, has established a new national benchmark for all such wildlife surveys in future.
The survey spans locations in North Kerala, which covers Palakkad, Malappuram, Kozhikode, Wayanad, Kannur and Kasargode districts. The area extends from the Ghats, through the midlands, to the seacoast, which lies north of Palakkad Gap.
The forest areas studied are the Silent Valley National Park, Mannarkad forest division, Nilambur North and South divisions, the Malabar Wildlife Sanctuary, the Wayanad Wildlife Sanctuary, Aralam Wildlife Sanctuary and their neighbouring areas as well as the Reserve Forests of Kasargode district and the wetlands of North Malabar.
Twelve locations, within them 58 sites and 103 transects, covering a distance of 2,200km were identified in the survey. This included six habitat types – tropical evergreen, tropical moist deciduous, tropical dry deciduous, Shola grassland, low elevation evergreen grassland and wetland areas.
The 341 species of birds surveyed comes to 73.27 per cent of all bird species so far recorded from Kerala. The survey could successfully estimate the density of 48 species of birds. Yellow-browed Bulbul is credited with the highest density (122.4 birds/sq km) followed by Small Sunbird with a density of 109.7.
The other high-density birds recorded are White-cheeked Barbet, Red-whiskered Bulbul, Black-headed Babbler and Oriental White-eye. Interestingly the density estimate also includes some of the skulking birds such as Indian Blue Robin, White–throated Ground Thrush and Spotted Babbler but the density of such birds could not be estimated during the Travancore-Cochin Survey 2009.
Density estimate for six migratory birds including Green Leaf-Warbler, Large–billed Leaf Warbler and Blyth’s Reed Warbler, and for some Western Ghat endemic birds such as Blue–winged Parakeet, Malabar Hornbill, Grey–headed Bulbul and Indian Rufus Babbler are also be obtained.
The survey also records the encounters of raptors, globally-threatened species of birds, rare birds, and abundant birds, as well as sightings of heronries of Malabar and breeding nests of birds. Of the 1,149 individual raptors belonging to 32 species encountered, 11 species are migrants and 21 residents. The two critically endangered vulture species, the White-backed vulture and Red-headed vulture, are sighted in Wayanad Wildlife Sanctuary, the only region in Kerala that supports these vulture species.
22 of the 341 species surveyed belong to globally-threatened category as notified by IUCN. Alarmingly, of the 22 threatened species 17 are residents and, of which 9 are specifically endemic to Western Ghat. 15 species of birds are found to be abundant in the region, of which two are migrants, and one endemic. They include Yellow-browed Bulbul, Small Sunbird; Green Leaf-Warbler, Large–billed Leaf-Warbler and the three species of Bulbuls including the Black Bulbul.
15 species are found to be rare with only one sighting for each. Syke’s Warbler, Indian Grey Hornbill, Jerdon’s Bush Lark and Sirkeer Malkoha are some of the rare birds recorded. 121 breeding records for 58 species, of which five records each are for Malabar Grey Hornbill and Small Sunbird, four for White-bellied Blue Flycatcher, one each for Nilgiri Laughing-thrush and Black and Orange Flycatcher, and two for Wayanad Laughing-thrush, all of which are endemic to Western Ghat.
The landmark survey was conducted by an efficient team of five ornithologists led by C. Sasikumar, the Chief Investigator, and his four research associates, C.K. Vishnudas, S. Raju, P.A. Vinayan and V.A. Shebin. The surveyors spent a year (from November 1 2010 to the middle of October 2011) during, which they had covered over 4000 km, trekking through treacherous forest areas enduring extreme weather conditions and threats from wild animals.

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