Ecology of Brown and Striated Thornbills in Forests of South-eastern New South Wales, with Comments on Forest Management

Abstract

Acanthiza pusilla and A. lineata often occur together, but striated thornbill forages mainly in the subcanopy and canopy (>75% of foraging observations) where it specialises in taking food from the foliage of eucalypts (>90% of observations). Brown thornbill forages mainly in the shrub layer (>70% of observations) and takes prey from bark, debris and the leaves of a large variety of plants including eucalypts. Both thornbills forage mainly by gleaning but striated thornbill commonly hang gleans (>20% of observations), a behaviour rarely used by brown thornbills. Striated thornbills are disadvantaged by logging, which reduces the amount of canopy and subcanopy vegetation, but brown thornbills benefit from the increased amount of shrub and ground vegetation that results. Conversely, brown thornbills are adversely affected by fires that reduce the amount of debris and low vegetation. In the absence of eucalypts, striated thornbills are absent from pine plantations, but brown thornbills may be abundant.