Roost-Tier Preference in Roost-Trees: A Case Study in the Bats <em>Pteropus giganteus</em>

The Indian flying foxes Pteropus giganteus are habituated to spend the day hours roosting in suitable roost trees. They are seen hanging here and there in a roost tree. It is not known whether they have preferred roost sites rather hanging spots in the concerned roost tree. To testify the said hypothesis we selected two roost trees, Albizia lebbeck and Tamarindus indica locating at distant places (75 km apart) in the arid zone of West Bengal, India during the period of last ten years. It is revealed that P. giganteus preferred branches of the roost tree which are locating in the mid-tier of tree. But depending upon the situations the less preferred sites are not spared as these sites are used by the late comers. Statistical tests following application of one-way ANOVA justified significant effect of the roost branch on the abundance of bat population (P<0.05), abundance of bats in the roost branches is highly correlated in respect to the study years (r=0.96) is also justified from the study of normality distribution plot, and the results of GLMM strongly support the hypothesis irrespective of the variables, that is branches of the roost tree and the year of observations (P = 0.0)