Low secondary risks for turkey vultures from a sodium nitrite toxic bait for wild pigs

Abstract

AbstractAn acute and orally‐delivered toxic bait for wild pigs (Sus scrofa) containing sodium nitrite (SN) is being developed and tested for potential registration in the U.S. We evaluated oral toxicity of SN and risk of secondary consumption in a common avian scavenger, the turkey vulture (Carthartes aura), by 1) conducting an acute oral toxicity test (LD50) for turkey vultures by oral gavage, and 2) allowing turkey vultures to feed on whole carcasses and digestive tracts of wild pigs that died from consuming SN‐laden bait. Captive tests were conducted during fall 2016 and spring 2017 in the Wild Pig Research Facility at Kerr Wildlife Management Area, Hunt, Texas, USA. We estimated the LD50 of SN for turkey vultures at 659 mg/kg. None of the turkey vultures died or exhibited any symptoms of SN‐toxicity from consuming whole carcasses, or digestive tracts of wild pigs that were poisoned with SN. We concluded that the risks of secondary poisoning to turkey vultures are low, which agrees with previous work on another scavenger, the coyote (Canis latrans). Overall, we found no evidence to suggest that 2 common scavengers would be at risk of acute mortality from consuming wild pigs that were poisoned with SN.