Abstract
Context Research on large, terrestrial mammals often requires physical captures to attach tags or collars, collect morphological data, and collect biological samples. Choice of capture method should minimise pain and distress to the animal, minimise risk to personnel, and consider whether the method can achieve study objectives without biasing results. Aims We studied how capture via helicopter net-gunning affected survival, post-capture movement patterns, and space use of exotic nilgai (Boselaphus tragocamelus) in southern Texas, USA. Methods We estimated daily survival rates for 101 collared nilgai over 28 days, following 125 captures. We calculated mean daily movement rates and net-squared displacement for 21 recaptured nilgai for 60 days, starting 30 days before capture. Key results The survival probability of 125 nilgai individuals was 0.97 (95% CI = 0.92–0.99) over the 28 days following capture, with the lowest daily survival for the day after capture ( x ¯ WR22049_IE1.gif = 0.99; 95% CI = 0.96–1.00). We observed an increase of ~65% in the mean daily movement rate of 134 m/h on the first 2 days since capture, followed by a period of reduced movement out to the 5th day before returning to pre-capture levels. Analysis of net-squared displacement for 21 nilgai showed that 17 resumed pre-capture space-use patterns within a week, whereas four individuals did not return to the pre-capture range for ≥1 month. Conclusions Capture-related mortality rates for nilgai using helicopter net-gunning in our study (3%) were similar or lower than those reported for similar species captured using the same method. While we were able to detect a period of elevated movement rates, followed by a recovery period of diminished movement as a result of capture, nilgai appeared to return to typical behaviour ~6 days post-capture. Most nilgai in our study also resumed typical space-use patterns within a week of capture; however, our results suggest high individual variability in their response. Implications We recommend using net-gunning from a helicopter as a method for capturing nilgai when conditions and where vegetation and topography allow. We suggest censoring data for a minimum of 7 days following capture for analyses related to survival and movement rates. For analyses relating to space use, we suggest inspecting net-squared displacement or some similar displacement analysis for each animal separately to account for individual variation in response and exclude data accordingly.
Subject
Management, Monitoring, Policy and Law,Ecology, Evolution, Behavior and Systematics
Reference45 articles.
1. American Veterinary Medical Association (AVMA) (2020) ‘AVMA guidelines for the euthanasia of animals.’ 2020th edn. (American Veterinary Medical Association: Schaumburg, IL, USA)
2. Evaluation of a hand-held net-gun to capture large mammals.;Wildlife Society Bulletin,1982
3. Effectiveness, economics, and safety of drop nets and helicopters with net-gunning for capturing white-tailed deer.;Wildlife Society Bulletin,2022
4. Impact of capture and chemical immobilization on the spatial behaviour of red deer hinds.;Wildlife Biology,2019
5. Evaluation of helicopter net-gunning to capture wild fallow deer ().;Wildlife Research,2021
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