Star finches. Photo: Mick Todd

From Tropical Topics newsletter, No. 73 May 2002, produced by Stella Martin at the Queensland Environmental Protection Agency. Download the PDF to read the whole issue.

Finches

Sub-species of star finches and crimson finches which were once widespread in Cape York Peninsula are now confined to two small populations on the east and west coasts of the peninsula. Studies have shown that changes in vegetation on Cape York may be the cause. Both birds depend on very dense grass. Star finches nest in it and crimson finches rely on it for shelter from predators while feeding. Trampling by cattle, and fires, however, have reduced the availability of this type of vegetation in drier areas. In places other than Cape York, where the finches still thrive, they seem to have benefited from agriculture, particularly sugar cane, which provides a similarly sheltered habitat.

More profound changes in the vegetation, brought about by cattle grazing and altered fire regimes are also affecting the birds. Coastal grasslands in Cape York are being steadily taken over by woodland, dominated by melaleucas and eucalypts. In addition, the types of grasses are also changing, with species favoured by the finches being replaced by those which are more resilient to grazing but which do not provide the finches with food. On the other hand, introduced grasses in agricultural areas, where the finches are not in trouble, may help to feed them.

Until recently, mystery surrounded the whereabouts of star finches in the wet season, after they disappeared from dry season feeding grounds around Princess Charlotte Bay. Then, in late 1999, flocks were discovered feeding in unburnt grasslands on saltpans near the sea. Star finches on the western side of Cape York, however, have a different strategy. They move into casuarina woodlands where they sit up on the branches picking seeds from the cones. To see a list of research findings on star finches click here .

The crimson finch subspecies ( Neochmia phaeton evangelinae ) found in Cape York and New Guinea has a white belly(above right) instead of the black belly seen on crimson finches elsewhere in Australia. Differences in the subspecies of star finch ( N. ruficauda clarescens ) are more subtle. Curiously the bills of both these endangered subspecies are smaller than those of their cousins* elsewhere. This means they cannot handle larger seeds efficiently (husking them is too time consuming) so the range of food available to them is more limited. To see a list of research findings on crimson finches click here .

*Sub-species elsewhere in Australia ( N. phaeton phaeton and N.ruficauda subclarescens ) although also declining in numbers, are thriving in some parts of the Northern Territory and Western Australia.

Gouldian finch

The bright colours of Gouldian finches have led to extensive trapping of these lovely birds for the caged-bird industry. These finches were once widespread in woodlands across northern Australia, flocks of thousands providing a spectacular sight as recently as 50 years ago. They have now disappeared from nearly half their previous range and numbers are continuing to decline. Populations in Queensland have been particularly badly affected.

Grazing and changes in fire regimes seem to be affecting seed availability. In the dry season, the finches are able to find seeds on the ground in recently burned areas and in the wet season they like to feed in areas which were burned in the previous dry season, targeting perennial grasses. However, if the areas burnt are too large, they have problems finding food. Gouldian finches seem to be persisting best in rocky areas, such as the Kimberley, where pockets of grassland remain ungrazed. Diseases have also been implicated but are not considered a major cause of declines.

Twenty Gouldian finches were recently released into the wild at the Mareeba Tropical Savanna and Wetland Reserve in north Queensland. They are part of an experimental breed-and-release program which aims to re-establish populations in an area where they have been absent for 25 years. The birds quickly paired up and have been nesting. To see a list of research findings on gouldian finches click here .