Predator-Proof Nests May Help Save Endangered Tassie Parrots

Tasmania’s critically endangered swift parrot population has dwindled to a mere 2,000.

They're a swift parrot's worst nightmare: cute but deadly sugar gliders.

As deforestation in Tasmania spreads to accommodate growing agriculture and logging industries, the region's critically endangered swift parrot population has dwindled to a mere 2,000.

In addition to losing access to the massive 75 metre trees where they lay their eggs, swift parrots have had a more difficult time evading the resilient population of sugar gliders.

The palm-sized mammals resemble squirrels but with larger eyes and more rotund bodies. They were brought to the region from mainland Australia as pets in the mid-19th century and, after being released into the wild, became an invasive species.

They've been uniquely good at adapting to regions subjected to deforestation, said Dejan Stojanovic, a conservation scientist from the Difficult Bird Research Group.

Stojanovic says the conservation group's name was inspired by the difficulty researchers have in studying the small, bright green birds. While their nesting grounds are in Tasmania, they also visit other parts of Australia and small surrounding islands in search of flowering trees. Not all trees flower every year, the researcher said, and while the birds have uniquely adapted to figuring out which trees supply their food source, scientists are still catching up.

"I always describe them as hyper caffeinated," said Stojanovic. That's because the birds quickly zip through the trees, chasing each other and "singing their heads off" to attract mates.

It's the habitats the scientists most easily located that have caused them the largest source of anxiety about the birds' descent toward extinction.

Their breeding grounds, the sites most critical to keeping their population numbers healthy, are infested with sugar gliders that feast on swift parrots' babies and eggs.

Stojanovic and a team of researchers from the Australian National University are hoping they can outsmart the small predators with a simple habitat they're calling the "possum keeper outer."

"It's a great name isn't it?" Stojanovic said, laughing. Despite the box's light-hearted name it's been seriously successful at protecting the small birds from the island's invaders.

The parrots have taken to the boxes, using them as nests. To keep the sugar gliders out, a small mechanised rectangle is attached to the outside of the box, near the circular hole the birds use to enter and exit. It's controlled by a light sensor that moves the door over the hole when it's dark, and opens it when it senses morning light.

The simple concept works because swift parrots are diurnal (awake during the day), while sugar gliders are nocturnal. In other words, when the parrots go in their nest boxes for the night, the door closes behind them, keeping them safe from predatory sugar gliders until the morning, when the predators are no longer active.

It's one small but effective way the Difficult Bird Research Group has attempted to protect the few "swiffies," as Stojanovic affectionately refers to them, that are left in the wild.

"I'm optimistic, but I'm also extremely cautious, and my caution exceeds my optimism," Stojanovic said. He emphasised that the boxes prevent sugar gliders from preying on parrot babies, but it's only a band aid on a gaping wound.

"At the end of the day if we continue to lose habitat—and there don't appear to be concrete changes to stop logging—it seems like deforestation is locked in. If that's the case, then all of this that we're doing is ultimately for nil."

Lead Image: The swift parrot. Photo from footage by Difficult Bird Research Group at Australian National University. 

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