Why do wild Gouldians need homes?
Until recently, thousands of Gouldians were regularly reported anywhere from Broome to Cairns. Today, however, individuals are largely restricted to small and isolated populations mostly in the Northern Territory and Kimberley regions of Western Australia. Obviously, something needs to be done. The big problem, however, is that the success of any conservation strategy depends on our understanding of the processes contributing to their decline – something we are finally starting to better understand....
The Problem – limited tree hollows
Declines in Gouldian finch populations were initially blamed on air sac mite and wild trapping of birds for the pet industry (banned in the early 1980’s). However, recent research suggests that the overriding factor is large-scale habitat change and inappropriate fire regimes, which not only alter seed diversity (directly affecting food availability), but can also affect the availability and production of Eucalyptus tree cavities (used for nesting).
Prior to the introduction of pastoralism in the nineteenth century, the fire regime in Australia’s northern savannas consisted of a patchy mosaic of regular (early dry season), low intensity grass fires. More recently, however, with increased pastoralism and reduced traditional land management, large areas are now susceptible to high intensity and late season fires. Although low intensity fires have a negligible effect on Eucalyptus demographics, high intensity fires typically destroy growing saplings and older trees. Cavity production in Eucalyptus woodlands is strongly related to the size and age of the tree, often requiring at least 80-120 years depending on species. In other words, trees planted now are unlikely to form suitable hollows for many decades to come.
The problem for the Gouldian finch is that they nest exclusively in tree cavities (they are unable to build their own free-standing nests). They are also very choosy about the hollows they will nest in, preferring very sturdy, deep hollows with narrow entrances (which are produced by older trees). Competition for these limited nest sites is fierce, with up to twelve pairs of birds often competing for access to a single hollow. There is also intense competition with the ecologically similar Long-tail finch, a competitively dominant species that typically outcompetes Gouldian finches for access to hollows. |
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The Solution – artificial nest boxes
Faced with all these problems, the big question is – what can we do about it? One solution is to provide artificial nest cavities in the form of nest boxes. Over the last three years, the scientists have been hard at work building specially-designed nest boxes (modelled on the natural tree cavities used by Gouldian finches). By providing artificial nest sites, we can increase the number of suitable Gouldian finch hollows (i.e. remove the constraints of the limited number of hollows available in the environment) and reduce the effects of competition (i.e. enough boxes for everyone to breed). The results have surprised even us – in areas with nest boxes, the number of breeding pairs has increased by over 200% and the number of offspring produced per pair has often doubled. This is an amazing success rate using a very simply solution. Now you can also help us to help the wild Gouldians.
The Nest-Box Project
The more boxes we can build, the more ‘homes’ we can provide for Gouldian finches, and the more we can boost both the population numbers and increase their range. All donations to this project are invaluable and will go a long way to reversing the decline in this endangered species.
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