The endangered Gouldian Finch Erythrura gouldiae is the only Australian finch to nest exclusively in tree hollows or, more rarely, in termite mounds. It is sympatric with the abundant Long-tailed Finch Poephila aculicauda which nests frequently in tree hollows. The aim of this study was to define the characteristics of nest sites and breeding areas of Gouldian and Long-tailed Finches to determine whether nest hollows were in short supply, and where finches fed relative to their nest sites. The Gouldian Finch chose hollows with smaller, more northerly entrances than Long-tailed, or randomly chosen hollows, nested deeper down the hollow and on steeper hill-slopes. Both species preferred single to multi-trunked trees of larger diameter than trees with randomly chosen hollows. Discriminant analysis classified 22–25% of the randomly chosen hollows and 28–38% of Long-tailed nesting hollows as Gouldian hollows. Gouldian Finches were more specific in their choice of nest sites than Long-tailed Finches. The vegetation at the two sites differed floristically, but within each site there was no floristic distinction between feeding or breeding sites or sites chosen at random. Gouldian Finches chose feeding habitat where trees were more spaced, on less rocky, barer ground than around breeding sites.
On the basis of the criteria measured, there was no shortage of suitable hollows available to the Gouldian Finch for nesting. The overlap between feeding and breeding sites indicates the importance of managing breeding habitat for conservation.