Extinction looms large for our birds

When celebrities such as Leonardo DiCaprio take to social media to champion Tasmania’s swift parrots, a species that faces extinction, awareness of the threat becomes global. The seriousness of the threat to birds was confirmed in a study published recently in the journal Emu – Austral Ornithology. It found Australian birds living on islands are among the species considered the most vulnerable to extinction and Tasmania’s swift parrots and orange-bellied parrots have been listed as critically endangered for some years according to the International Union for the Conservation of Nature’s criteria, with just 750 swift parrots estimated to be left in the wild.

Lead author George Olah, an Early Career Researcher Award Fellow at the Australian National University’s Fenner School of Environment, said although Australia had over 750 bird species many of them faced an uncertain future.

“The numbers are quite sad. By 2020 eight species were already considered extinct, and 74 were threatened with extinction, but some species are more prone to extinction risk than others, and our study identified three significant factors,” Olah explained.

Habitat loss, human persecution and introduced predators were found to be the main threats to birds globally, and species with a larger body size and lower fecundity rates were associated with a greater risk of extinction. Bird species that struggled to adapt to habitat cleared for agriculture were also under threat, as were those with evolutionary distinctiveness.

“The more able birds are in finding food in agricultural areas, and able to adapt to take advantage of new agricultural lands – perhaps after some of their habitat has been destroyed to make way for it – the less endangered they were predicted to be, but the burden of extinction risk seems to disproportionately impact species that have high uniqueness,” Olah said.

Researchers came up with a score based on aspects such as the number of other species there were within the larger bird family, with indications that some shared traits formed a larger pattern. Slow breeders that had a larger body size, and were possibly longer-lived, generally found it harder to cope with environmental changes.

The study calculated the IUCN’s Red List for all Australian birds and found the increase in extinction risk that occurred between 2010 and 2020 was over 50 per cent due to the 2019-2020 bushfires. The greatest increases overall were in Queensland, South Australia, and New South Wales where drought and wildfires were pronounced.

Olah said the study highlighted the importance of phylogenetically informed conservation prioritisation as the loss of evolutionary uniqueness would have major consequences for Australia’s bird diversity, and that would influence ecosystem functioning.

Anne Layton-Bennett

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