Roost ecology, population size, behavioral patterns and morphometric analysis

The present study was conducted at Krishnai Forest Range Office Campus (26°2′ 0″ North, 90°40′ 0″ East) situated at Goalpara district of Assam. Throughout the pre-monsoon season (March-May 2022), the survey location was periodically visited. The current study aims to identify the numerous roosting trees used by Indian flying foxes (P. medius), their diurnal behavioral pattern, and to assess the population size of the species together with their morphometric variations. A large mean colony size (5479 332.99) of P. medius bats was found in the study site, residing in a number of preferred roosting trees (n = 101). In April 2022, a population count of 5509 bats was recorded as the mean population size. However, the population count varies in March (5871) and May (5057). Population fluctuation was mainly due to inter-colony migration and other environmental factors. A very high population density of 4094.91 was recorded. Direct roost count method was used to estimate the population size following standard literature key (Bates and Harrison, 1997). Different times of the day were used to record the diurnal roosting habit patterns of the bats. The most frequent behavior was sleeping, which was followed by grooming, wing flapping, and wing spreading. Two of the few captured bats (n) were used to analyze the morphometric variances. The average body weight of the specimens that were caught was 699 ± 26.87g, and the average forearm length was 172.05 ± 2.616g. When compared to the caught (P. medius) bat species, the mean value of the morphometric measurements revealed a substantial variation. Roosting site selection depends on their abundance, risk of predation, availability and distribution of food resources and physical environment. An essential species for maintaining the ecosystem's equilibrium is the Indian flying fox. For the reforestation of the forest environment, it is regarded as a crucial method of seed dissemination and pollination.