Damage to oat crops by the Tasmanian native hen, Tribonyx mortierii

Abstract

Damage by native hens, Tribonyx mortierii, grazing on young cereals constitutes their chief importance to agriculture. Native hens were responsible for a reduction of weight of yield, at 6-8 weeks after sowing, of 24-36% on the immediate edge of the one margin of a paddock that bordered water. For the entire paddock, the overall reduction of weight attributable to native hens was 8%. The grazing pressure of native hens was greater than that of rabbits on the edge nearest water, but the situation was reversed over the rest of the paddock. Even though the rabbit population was low because of earlier and more recent poisonings, damage attributable to rabbits was equal to damage by native hens. Clearance of the rough vegetation around the small paddocks near water, where damage by native hens occurs, is the best permanent remedy. When this is impracticable, local poisoning may be necessary. Widespread control campaigns are unnecessary and indeed are undesirable, as this flightless bird is conked to Tasmania and could become extinct.