Social Behavior and Movement Ecology of Nilgai Antelope
[Thesis]
Zoromski, Lisa Diane
DeYoung, Randall W
Texas A&M University - Kingsville
2019
124 p.
M.S.
Texas A&M University - Kingsville
2019
Nilgai antelope (Boselaphus tragocamelus) are an exotic ungulate species in Texas. Native to India, Nepal, and Pakistan, nilgai have expanded into much of coastal southern Texas and northeastern Mexico since their introduction in 1924-1949. The presence of nilgai in Mexico and South Texas has complicated the eradication of cattle fever ticks (CFT; Rhipicephalus annulatus and R. microplus). Cattle fever ticks can transmit bovine babesiosis to cattle, a serious economic threat to the U.S. cattle industry. With CFT quarantine areas established in South Texas, ranches with infested cattle must comply with extensive eradication requirements. Wildlife can hinder eradication efforts because white-tailed deer (Odocoileus virginianus) and nilgai are alternative hosts for CFT. Control methods, such as acaricide-treated baits, are available for deer. Nilgai do not respond to bait, which is a major challenge for controlling the spread of CFT. One unique aspect of nilgai ecology is their use of latrines, or repeated defecation at a localized site. In addition, nilgai are not impeded by standard livestock fencing, and often push under fences at well-established crossing sites. The existence of these repeatedly visited areas present an opportunity for CFT treatment through application of acaricides using remotely activated sprayers. With limited information on nilgai ecology, there is pressure to understand nilgai latrine and fence crossing behavior to design efficient CFT treatment measures. I analyzed the density, size, activity, and placement of nilgai latrines. I used trail cameras to assess frequency, time of day, sex, and age of nilgai that used latrines and all animals that used fence crossings. Also, I used genetic markers to determine how many individual nilgai use latrines. Knowledge of nilgai movement and behavior will help identify areas to target with remotely activated acaricide sprayers. The results of this study will have important implications for the development of treatment methods for eradication of CFT in the U.S.