Residential Population Structure and Abundance of Nilgai, Boselaphus tragocamelus, (Pallas) in Bihar, India

Nilgai (Boselaphus tragocamelus) is one of the most discussed animals after cow in agrarian society of India. However, conflict between farmers and Nilgai due to its habitat loss and the increased damage to the crops by this wild species in the agricultural lands. Present paper deals with the study conducted on the population structure, size group and abundance of Nilgai inhabiting Shahabad region in Dumraon (Buxar) Bihar, India from January, 2014 to December, 2015. Survey was performed in the morning to evening time on the specific days by motorcycle and walking, where, there was no local footpath due to difficult, undulated study area. The direct methods utilized sighting of animals carefully from a close distance and behavior of the animal were observed. During the course of study 07 herds with total 407 numbers of Nilgai were counted through direct sighting with from closed distance. The density of Nilgai was found under 431.10 acre are as covered in Haryana Cattle Breeding Farm (HCBF) and its surrounding in Dumraon. The sex ratio of Nilgai with age group structure of the population was represented in percentage. Female biased adult male, ratio was found 1:3. While overall sex ratio was found 14.25% male, 38.57% female, 9.58% semi adult male, 20.15% semi adult female, and 18.46% calves respectively. Female Nilgai has been observed social like behavior and grazing with juveniles in a group but males were found in scattered form. Nilgai migrate for food towards agricultural land during dusk and return to HCBF with less human activity during dawn. This shows mark migration behavior during summer and rainy season. Some Nilgai migrations were observed for searching food and water during summer from south upward plain region of Dumraon to low-lying north plain area near Bhagar oxbow lake Simri, Chakki and Brahampur.