Strychnine poisoning was diagnosed in free-flying mallards (Anas platyrhynchos) and a ring-billed gull (Larus delawarensis) found dead on a pond in a zoo. The probable source of toxin was improperly applied strychnine-treated grain used for control of rodents on adjacent farm land. Ingesta of the birds contained 19.7–85.1 mg/kg of strychnine.