Above: A positive sight: a regent honeyeater nest means birds are breeding. Photo: David Stowe
THE BEST CHANCE for the survival of the Critically Endangered regent honeyeater (Anthochaera phrygia) is for its fast-disappearing habitat to be protected. And scientists say the same goes for many species in decline, where shrinking habitat ranges create smaller isolated populations, which drastically reduce mating options and, therefore, genetic diversity.
In the case of the regent honeyeater, researchers from the Australian National University (ANU) discovered that the diversity of its genetic make-up remained intact.
“Birds in the north of the range are closely related to both their near neighbours and birds in the south of the range,” said Dr Ross Crates of ANU’s Difficult Bird Research Group, which carries out conservation research into birds endangered now or likely to be in the future but whose rarity and mobility makes them tricky to study.
“This strongly suggests that small numbers of birds are travelling long distances to breed with each other,” he added, “The birds’ long-distance movements are naturally helping to maintain genetic diversity in the population.”
Tracking down such a small number of birds (as few as 250 in the wild due to loss of breeding habitat and increased competition with larger bird species) in such a huge area (their range stretches some 600,000 square kilometres) was a challenge for researchers. In order to make comparisons between DNA of the bird when it was common and current populations, they had to extract DNA from museum specimens.
The study, published in scientific journal PLOS ONE, stated that “a rapid population decline, coupled with the regent honeyeater’s high mobility, means a detectable genomic impact of this decline has not yet manifested. Extinction may occur in this nomadic species before a detectable genomic impact of small population size is realised.”
This is why, according to Dr Crates, “our best chance of saving regent honeyeaters from extinction is by protecting remaining breeding habitat, restoring as much lost breeding habitat as possible and protecting nests from predators.”
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