Lead poisoning in six captive avian species

Red-winged blackbirds (Agelaius phoeniceus ), brown-headed cowbirds (Molothrus ater ), common grackles (Quiscalus quiscula ), mallards (Anas platyrhynchos ), northern bobwhites (Colinus virginianus ), and eastern screech-owls (Otus asio ) were poisoned with a concentration of lead (Pb) acetate in the diet which was increased by 60% each week until half of the birds in each treatment group died; surviving birds and all control birds except screech-owls were then killed by euthanasia. An additional group of mallards was poisoned with Pb shot. The gizzards of mallards poisoned either way usually were stained with bile; some of these birds also had proventricular impaction.