Abstract
Distributional range, population trend and factors regulates the occurrence of a species are often required for conservationist and managers to implement management activities. In this context, the work addressed few issues pertaining to distributional range and factors influencing the distribution of owls in the southern Western Ghats with the support of GIS and landscape level modelling tools. Standard sampling and survey protocols identified for owls were followed. Since owls are raptorial in nature, factors influencing the occurrence of owls were assessed at two scales: patch and landscape scale. Surveying owls during night hours in the elephant dominated landscapes like Western Ghats is not practical. Hence, based on the occurrence and non-occurrence of owls in a sampling point, two modelling approaches viz., presence only and presence-absence model were applied to predict and quantify the extent of suitable sites available for six species of owls in the southern Western Ghats.
Altogether, 276 points across 24 forest stations were surveyed. Call playback of conspecific calls was found appropriate method for lesser owls while dusk watch and initial quiet listening methods for large and moderate owls. Six hundred and eighty five owls belonging to 13 species were documented. Short-eared owl in Peechi-Vazhani Wildlife Sanctuary and Ceylon bay owl in Idukki and Neyyar Wildlife Sanctuaries were new records from the study. Patch characteristics around sampling point influence occurrence of lesser owls however, landscape characteristics influence large and moderate owls. Extent of suitable sites available in southern Western Ghats to Jungle owlet (24% of southern Western Ghats), Indian scops owl (24%), Oriental scops owl (25%), Brown hawk owl (26 %), Brown fish owl (31%) and Indian eagle owl (7%) were quantified by employing free spatial data and open source software.
Large tracts of deciduous with undisturbed riparian forests are needs to be secured for sustaining current population of owls in the southern Western Ghats. Further, forest areas falling over the juncture of wet (rain fed) and dry zones (rain shadow) support a wide array of owl species as a result of diverse eco-climatic zones and therefore, conservation of these unique patches is suggested.
Dr S. Babu works as Scientist (Ornithology) at Salim Ali Centre for Ornithology and Natural History, Coimbatore.