Proceedings of the Vertebrate Pest Conference

Tracerite®, the chemical marker used in M-44 cyanide capsules, contains cadmium which the Environmental Protection Agency identified as an inert ingredient of toxicological concern. An alternative nontoxic marker was identified and tested. In a weathering test, capsules with Day-Glo® performed as well as those containing Tracerite, and presence of potassium chloride in the capsules did not improve capsule function. Day-Glo was further tested by allowing captive coyotes to discharge M-44s containing sodium cyanide and various colors of Day-Glo. Twelve of 13 coyotes that died or were euthanized soon after recovering from sublethal doses had obvious marks in their mouths for 4 to 5 weeks. On the basis of these tests, the registered formulation for M-44 capsules was changed; Tracerite and KCl were deleted and Day-Glo Blaze Orange was added.