Effects of translocation on American crocodile movements and habitat use in South Florida

The range of the threatened American crocodile (Crocodylus acutus) in the United States is limited to the southernmost parts of Florida. As this species has recovered concurrently with an increasing human population, human-crocodile conflicts have also increased. Resolving conflicts can involve translocating crocodiles; however, they often return to the site from which they were removed. We examined the effects of translocation on crocodile movements, habitat use, body condition, and survival in Florida, USA, in 2018-2019 to refine recommendations for managers considering translocation to resolve human-crocodile conflict. We captured and attached global positioning system (GPS) units to 17 crocodiles, 10 of which served as a reference group (free-ranging crocodiles released at their capture site) and 7 served as a treatment group (crocodiles that were translocated 14-158 km from their capture site). We collected location data from individual crocodiles for 34-661 days ((x) over bar similar to 250 days for each group). Body condition was similar for both groups. Corticosterone levels measured periodically during handling indicated that crocodiles experienced increasing stress levels during handling. Three crocodiles translocated <= 45 km from their original capture site returned to that location within 13 days. Three crocodiles translocated >= 110 km did not return. One female translocated 152 km was recaptured 0.42 km from its original capture site 965 days after its release. We identified 2 states of characteristic movement patterns: state 1 indicated individuals moving slowly and somewhat randomly, and state 2 indicated individuals exhibiting fast, active directional movement. Translocated individuals were more likely than reference individuals to switch to, and stay in, state 2. Because of concerns regarding return rates and heightened stress as a result of capture and translocation, we suggest crocodile translocations have limited conservation value and may only be worth considering once all other reasonable options are exhausted.