Status, abundance and population ecology of Nilgai (Boselaphus tragocamelus Pallas) in Aligarh District, Uttar Pradesh, India

Abstract

The data on population ecology of nilgai was collected in Aligarh District, Uttar Pradesh, India from August 2013 to June 2014. A total of 108 herds of nilgai 54 in each season (summer and winter) were encountered, respectively. The density of nilgai was found 0.49/km2 in Aligarh district. While the encounter rate was found 0.66individuals per km. There was a mark seasonal change seen in group size of nilgai i.e. 11.38 ± 2.76, and 22.83 ± 5.40 in winter and summer, respectively. The overall mean group size was found 17.10 ± 4.08. The sex ratio of nilgai was female biased, adult male:adult female ratio was found 1:3 while overall sex ratio was found 61.55%,26.32% and 44% male, yearling and calves on per 100 females, respectively. The nilgai shows mark seasonal change in their group structure. The group size was found maximum at 25% in 0-5 individual category and minimum 9.25 in >21 category in winter, while about 30% were seen in >21 category and only 11% were seen in between 0-5 category in summer season. Thus, the nilgai was found less sociable in winter and more gregarious in summer season.