Above: A group of Gouldians drinking at a waterhole in the northernmost region of Western Australia. Photo: Minden Pictures + Alamy Photo
ENDANGERED WILD BIRDS and other species can now be tracked through samples taken from watering holes where they drink.
Researchers from Charles Darwin University in Australia used environmental DNA (eDNA) to detect the movements of the Gouldian finch, a species native to tropical savanna woodlands and once numbering many thousands but now down to just 2,500 adults in the wild.
The finches are found in small groups across the vast, sparsely populated north of Australia, making it difficult to track changes in their numbers from year to year.
However, the strikingly coloured bird has to find water to drink several times a day. The research team realised they could develop a test to identify estrildid finches such as the Gouldian from a fragment of mitochondrial DNA, and a probe designed to register Gouldian finches specifically. This was important as several estrildid species would likely flock to the same waterhole and it was necessary to be able to separate the Gouldians from masked finches (Poephila personata) and long-tailed finches (P. acuticauda).
Team leader professor Karen Gibb said: “By having primers that pick up other finches it tells us the eDNA is good enough quality to be amplified. If the Gouldian test is then negative, we can be confident that the eDNA test worked, but there just weren’t Gouldian finches at that site.”
A 200ml (about 33 teaspoons) water sample allowed them to spot Gouldian finch eDNA from waterholes the birds had visited up to 48 hours before and it was still measurable from the samples two weeks later.
“This is essential information to guide land management decisions that will assist the recovery of wild populations,” said Prof Gibb.
“When it worked in the real world at the waterholes, even where the water was poor quality in places, we were really excited.”
The study, published in Endangered Species Research, opens up new ways for wardens, scientists and conservationists to monitor birds’ movements with a simple cup of water.
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