Wildlife play an important role in the emergence of livestock diseases and their movements can complicate disease management efforts. One of the most significant vector-borne diseases of livestock worldwide is bovine babesiosis, spread by cattle fever ticks, Rhipicephalus (=Boophilus) microplus and R. (B.) annulatus. Although cattle fever ticks were eradicated from the U.S. by 1943, bovine babesiosis and cattle fever ticks are prevalent in México. Recently, management of cattle fever ticks in the Texas-México region has been complicated by the presence of free-ranging, exotic nilgai antelope (Boselaphus tragocamelus). Nilgai are abundant, are competent hosts for cattle fever ticks, and make long-distance movements. The goal of this study was to better understand nilgai movements and space use to inform cattle fever tick treatment strategies. We analyzed hourly locations from 40 GPS-collared nilgai in Cameron County, TX, USA, from April 2019–September 2020. We assigned each nilgai a movement behavior using the net squared displacement metric. We estimated nilgai home range sizes at different temporal scales (monthly, seasonally, and overall) using Brownian bridge movement models. We calculated average movement metrics, activity patterns, and space use of nilgai using the Euclidean distance between locations. We observed movement patterns consistent with residency (52.5%), seasonal movers (17.5%), dispersal (5%), and unclassified (25%). Two young females made separate dispersal movements of about 40 km from their initial capture location. Overall, nilgai had large and highly variable home ranges: annual median home range estimate for females was 563 ha (range = 105–1,545) and for males was 937 ha (range = 221–1,602). Peak nilgai movements occurred during crepuscular hours, and median hourly movement for females was 57 m/hr and for males was 66 m/hr. Nilgai home ranges and long-distance movements have the potential to overlap multiple ranches, as the typical ranch size in South Texas ranges from 250–6,000 ha. Female dispersal can increase the rate at which viable nilgai populations can be established in new areas with implications for disease spread and management. Understanding these behaviors will help the Cattle Fever Tick Eradication Program develop more efficacious treatment strategies to treat infestations in nilgai.

Nilgai_41: Data are hourly locations from 40 nilgai antelope (Boselaphus tragocamelus) from 1 April 2019 through 30 September 2020. Time span varies for most individuals due to recapture and removal of collars to deploy elsewhere or mortality event. Easting and northing are WGS 84, zone 14.

Nilgai_movement_caps: Locations of 21 Nilgai for the 60-day period centered on capture. Nilgai were captured using aerial net-gunning.

Nilgai_movement_ID: contains the sex and age information for individuals in the Nilgai_movement_caps dataset.

Nilgai_sirvival_data: Survival data for 125 captured nilgai for 30 days where day 0 is day of capture. Nilgai were captured using aerial net-gunning.