An Ecologically Founded Design for a Targeted Non-Lethal Predator Aversion Device to Protect Agassiz Desert Tortoises from Depredation

Kingsley, C., and Jenkins, M.

The 2019 Desert Tortoise Symposium, Tucson, AZ (February 2019)

Desert tortoises (Gopherus agassizii), currently listed as threatened under the Endangered Species Act (ESA), are experiencing depredation at unprecedented and unnatural rates due to the growing presence of human-subsidized predators in desert tortoise habitat, namely ravens (Corvus corax) and coyotes (Canis latrans). While a multipronged approach addressing the complexities of the issue will likely provide the most comprehensive, sustained solution (i.e. reducing trash, landfills, human food sources, and infrastructure in desert tortoise habitat), one smaller-scoped solution with the potential for immediate impact is training predators to stop preying on desert tortoises through highly targeted, non-toxic, and non-lethal aversion strategies. Charles River Analytics seeks to develop a scalable, low cost, modular device that can effectively identify predators and dynamically deploy repeatable, extensible, and diverse predator-specific aversion tactics to protect a variety of at-risk species without disrupting healthy predator-prey cycles. To this end, Charles River Analytics has defined initial designs and will be prototyping an animatronic desert tortoise decoy device equipped with a variety of non-lethal and non-toxic aversion stimuli (i.e. light, sound, vibration) to enable context-aware predator aversion strategies upon attack, initially targeting ravens and coyotes. For example, ravens identify juvenile desert tortoises on the desert floor through visual cues and fly down to attack by flipping the juveniles over and pecking through their softer plastrons. A visually-accurate decoy device could bait and detect this interaction and trigger a green laser towards the raven, a tactic shown to deter ravens. This effort will employ a hybrid approach of empirically- and ecologically-founded aversion strategies and iterative testing. This presentation will provide early design foundations and their links to desert tortoise ecology, as well as key considerations for this effort; effectively baiting predators, intelligently identifying interactions and selectively deploying tactics, avoiding habituation to aversion strategies, and maintaining healthy balances within the natural environment.

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