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ABSTRACT

Chatterjee A., Adhikari S., Barik A., Mukhopadhyay S.K. 2013. The mid-winter assemblage and diversity of bird populations at Patlakhawa Protected Forest, Coochbehar, West Bengal, We compared avian community structure of six contrasting habitat types at Patlakhawa Protected Forest of Dooars of West Bengal. During three weeks of the mid-winter studies 154 bird species representing 41 families were recorded. Of the 154 recorded species, 22 were observed in grasslands, 22 in swamp forest, 46 in riverine forest, 52 at miscellaneous plantation areas, 43 at forest edges and 51 at wetlands. The Shannon-Wiener general diversity indices varied among the habitats and ranged from 2.323 to 3.458. Richness (5.813-11.410), evenness (0.406-0.641) and dominance (0.042-0.128) indices also varied considerably among the study locations. The highest diversity, the lowest dominance and a very high evenness were characteristics of miscellaneous plantations. Grasslands showed highest evenness and considerably high species diversity. The lowest avian evenness and diversity were recorded in wetlands and swamp forests. Insectivorous birds were most numerous (53), followed by carnivorous (40), omnivorous (29) and frugivorous (15) birds. Winter appeared to be the best time for niche occupancy at the Himalayan foothills for assemblages of either winter migrants and visitors or altitudinal and passage migrants, as about 30% of all encountered species were migrants. 96 bird species were observed to occur at any one of these habitat types showing high habitat fidelity. Mixed avian foraging assemblages that varied in species number and compositions were observed and they contain 11 to 17 species. Avifaunal niche diversity and richness in different habitats of Patlakhawa Protected Forest during mid-winter envisaged its importance from conservation point of view.

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The present investigation is conducted to study the year wise (2011 to 2018) changes of water hyacinth (Eichhornia crassipes) cover at Santragachi Lake a Wetland under National Wetland Conservation Programme of India. Further the relationship between water hyacinth cover and the most abundant migratory waterbirds of Satragachi, Lesser Whistling Teal (LWT; Dendrocygna javanica) is assessed because this bird species is fully depended on water hyacinth mat for their roosting. The study comprises of eight satellite images procured from Google earth (2011 to 2018) to explore this relationship. A marked decline in the number of LWT at Santragachi wetland is observed in the year of 2017 and 2018. It is very interesting fact that from 2017-2018, the water hyacinth mat of this wetland is almost cleared before winter and the result of cluster analysis supports this fact. Significant positive correlation is also observed within LWT number and water hyacinth cover area (r = 0.7481 at p< 0.05) along with the total perimeter (r = 0.8648 at p< 0.05) of the water hyacinth islands at Santragachi wetland. However, open water area is also needed for diving, swimming, food searching for the LWT and other waterbirds. Therefore, more study is needed to optimize the clearing operations, focused on optimizing shape and size of water hyacinth islands for proper management of the waterbirds habitat.