The Sensitivity of Australian Animals to 1080 Poison. Vii. Native and Introduced Birds.

Abstract

Birds in Australia vary greatly in their sensitivity to 1080 poison (sodium monofluoroacetate). Median lethal doses (LD*50s) range from 0.63 mg kg-1 for red-browed firetails, Emblema temporalis, to approximately 278 mg kg-' for the emu, Dromaius novaehollandiae. Significant differences occur between the sensitivity of different groups of birds and may be related to differences in their metabolic rates. A few species may also have developed a tolerance to 1080 from being exposed to indigenous plants that contain fluoroacetate, or to insects and other animals which have fed on such plants. The most common signs of 1080 poisoning among birds are depression, fluffed feathers, a reluctance to move, and convulsions. Signs of poisoning first appeared among the species tested at 1-60 h after dosing, and deaths follow between 1 h to almost 11 days after dosing. The susceptibility of 48 species of birds in Australia to 1080 poisoning is discussed in relation to typical baits and poison concentrations used against vertebrate pests. Theoretically, fewer types of birds are likely to be at risk from dingo-poisoning than pig-poisoning campaigns that also use meat baits but higher concentrations of 1080. Individuals of 39 out of the 48 species could be at risk from rabbit and other pig-poisoning campaigns. The impact on bird populations will depend, among other factors, on the amount of bait individuals eat and on the poisoning methods employed.