DOI: 10.5061/dryad.c866t1g92
title: Hourly locations and survival data of Nilgai Antelope (Boselaphus tragocamelus) in South Texas

description: 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.
description: Nilgai_41: Data are hourly locations from 40 nilgai antelope
 (<em>Boselaphus</em> <em>tragocamelus</em>) 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.