Altitudinal Variation of Avian Fauna from Kalimpong Town to Nokdara of West Bengal, India

The spatial distribution of bird species across altitudinal gradients is governed by a complex interplay of ecological and biogeographic factors, making this relationship a central focus in avian research. The Kalimpong Town – Nokdara stretch study region examines important study sites within the 80 Km range. It was subdivided into three zones with altitudinal ranges: which are, Pudung Khasmal, Relli, and the lower part of Lolay (less than 1000 m asl); upper Lolay to Budhabare (1000 -1500 m asl); Gitdabling, Nokdara, and Lava (greater than 1500 m asl). This preliminary study documented 48 avian species representing 25 distinct families within the study area. Avian species composition varied significantly across elevational gradients, with the highest species diversity and richness observed in low-elevation zones (<1000 m asl). This pattern may be attributed to greater vegetation diversity at lower elevations, which provides enhanced shelter and more abundant food resources, supporting a wider array of bird species. Concerns regarding ecological imbalances and possible long-term behavioural changes are raised, for example, by the concentration of species near waste disposal sites.