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From brightly coloured birds to the much-loved sugar glider, Australia’s native animals are a sight to behold.

The island continent is home to  plants, animals and insects, many of which are found nowhere else in the world.

Tragically, though, we’re  of these species to habitat destruction and climate change.

Worse still, conservationists are increasingly seeing one native species threaten the survival of another. One example is the critically endangered regent honeyeater, currently being threatened by native possums and gliders.

���ܰ��� shows this trend could mean at-risk bird populations go extinct much earlier than they otherwise would.

Why native birds matter

Australia has  native bird species – more than almost anywhere else in the world. And they’re a  of our unique ecosystems, helping to spread pollen and seeds and ensuring some plants and animals don’t become too numerous.

But many bird species are now at risk from ongoing  of our natural environment through land clearing, urbanisation and the introduction of pest species.

Clearing land to make way for farms or houses has hit Australia’s woodlands particularly hard.  are full of trees and shrubs, like forests, but have have thinner canopies to let more sunlight in.

Since European colonisation, we’ve cleared  of many temperate woodlands in Australia. As a result,  of our unique native woodland birds are currently in decline.

When one native species threatens another

Native predators and prey are generally able to coexist. If a predator drives its main food source to extinction, it would threaten its own survival. This rarely occurs in nature.

Usually, two native species maintain their coexistence through an . If the predator gets faster or smarter, the prey follows suit.

But if prey numbers suddenly drop due to other factors – such as habitat loss and  – even occasional attacks from a native predator could push a species over the edge.

�ճ���� is a prime example. Less than a century ago, these striking black-and-yellow birds  the forests and skies of southeastern Australia in flocks of hundreds. However, they’re now on the  due to the effects of habitat loss and increased competition. Today, there are  regent honeyeaters left in the wild.

In our , we looked at how predation by possums and gliders – which  bird eggs and nestlings – may affect the survival of regent honeyeaters.

We found even occasional predation by these two species increased the regent honeyeater’s chance of going extinct in the next 20 years by 35%. This is significant because infrequent predation by a native species doesn’t typically threaten the survival of native prey.

This matters more because regent honeyeater numbers are so low. If there were 1,000 of these birds alive – the  there were in the 1990s – our research shows predation by possums and gliders wouldn’t have the same impact.

An ethical dilemma

The case of regent honeyeaters, possums and gliders is an example of a “conservation conflict”. These conflicts arise when protecting one native species may come at the cost of another. For example,  predate on regent honeyeaters, but they are also  in multiple Australian states. So efforts to protect regent honeyeaters from predation by possums and gliders may interfere with squirrel glider conservation.

Conservationists have limited options when it comes to stopping predators eating threatened bird species. At present, the only widely used method is killing predators.

Culling invasive predators  for conservation in certain situations. For example, in Australia we routinely cull �����Ի��� populations to protect native species and livestock.

But it’s much more contentious to kill one native species to protect another, especially when the predator species isn’t the main cause of decline.

Yet if we do nothing, we might lose endangered species – such as the regent honeyeater – forever.

So, what can we do?

To protect possums, gliders and regent honeyeaters, it’s vital to bring back woodlands. Governments and conservation organisations are  to restore habitat for regent honeyeaters.

Even so, it can take years to  these areas. And while endangered bird populations remain low, predation by other native species will remain a problem.

That’s why researchers are investigating ways to protect threatened species without killing predators. One approach is spreading  to deceive predators. Another is using  to protect nests.

These methods are promising, but won’t work everywhere.  shows possums don’t use bird odour to find nests, so spreading smells around is unlikely to affect them. Gliders also  through tree canopies, so tree collars likely won’t stop them accessing nests.

As we lose more of our native animals, these conservation conflicts will only become more common. But to save the regent honeyeater, we must explore new non-lethal ways of managing predation by possums and gliders. Hopefully, these will help us protect other endangered species too.

Main image

Australian regent honeyeater. Photo: Ken Griffiths/Adobe Images

Research

McBryde, B. et al 'Herbivores as predators: how an arboreal herbivore encounters and impacts declining bird populations' ( Volume 318 June 2026). DOI: 10.1016/j.biocon.2026.111855

Declaration

The authors declare no competing interests. Funding was received from the Taronga Conservation Society Australia�����Ի���Birdlife Australia [Taronga Conservation Society Australia Field Grant 2023]