Saturday 1 June 2024

Brush-tailed, burrowing bettong populations increase at Newhaven Wildlife Sanctuary.

Extract from ABC News 

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Bettong numbers have increased at Newhaven Wildlife Sanctuary.(Victoria Ellis)

A survey of brush-tailed and burrowing bettongs in remote central Australia has revealed some positive results for the rare mammals.

Newhaven Wildlife Sanctuary, about 350 kilometres north-west of Alice Springs, has been using a capture-recapture survey method to estimate the number of bettongs in the 9,400 hectare fenced block.

A woman's face is framed by her arm, which she lifts above her head to hold a bag. Her headtorch shines against black night sky.
Sam Mulvena weighs a bettong in a bag.(ABC Alice Springs: Victoria Ellis)

Wildlife ecologist Tim Henderson said 92 brush-tailed bettongs and 100 burrowing bettongs had been caught in three weeks, but population estimates were 136 and 161 respectively.

"[It's] much better than we expected," he said.

"Last year we only got about 50 to 60 of each species over the whole survey, so we're already well past that mark. It's pretty exciting."

Torchlight illuminates two hands opening the top of a trap to reveal the head of a tiny brown bettong and it's pink nose.
Tim Henderson says 192 bettongs were caught during the survey.(ABC Alice Springs: Victoria Ellis)

Working at night, the survey teams also collected data including weight, parasite load, DNA samples, location and general health.

They also microchipped any new bettongs they trapped.

Why are the bettongs doing well?

Bettongs had been extinct from the central desert for more than 60 years, until brush-tailed bettongs were re-introduced three years ago and burrowing bettongs were re-introduced two years ago.

Mr Henderson said high rainfall over the past few years had helped both species increase in number.

The start of the year brought huge rains to the desert regions north west of Alice Springs, including 316 millimetres at Newhaven in March — the wettest March at the sanctuary on record.

Two photos: A portrait of Tim smiling at the camera in the dark, next to a picture of Tim bending over a trap to check it.
Tim Henderson worked late to check the traps.(ABC Alice Springs: Victoria Ellis)

Mr Henderson said it caused vegetation to grow and increased available food sources for the bettongs.

"And of course, being in a predator proof sanctuary, there's no outside feral predators, like cats or foxes, impacting their population," he said.

Newhaven Wildlife Sanctuary, operated by the Australian Wildlife Conservancy, is the largest feral-free area in Australia, due largely to it's 1.8 metre high, roughly 45 kilometre long fence.

Two people have head torches turned on as they inspect a bettong at night.
Sam Mulvena and Tim Henderson process a bettong by torchlight.(ABC Alice Springs: Victoria Ellis)

What are bettongs?

Brush-tailed and burrowing bettongs are omnivorous, nocturnal "little kangaroo-looking" marsupials that grow to about 1.5 kilograms.

Field ecologist Sam Mulvena said bettongs could only be found in fenced off areas around mainland Australia.

The spiral shaped hairy gray tail of brush tailed bettong sticks out from a blue bag. It's being held on a man's lap.
A brush tailed bettong is inspected by the team.(ABC Alice Springs: Victoria Ellis)

"[The brush-tailed bettong] carries their nesting material in a little prehensile tail, that's what differentiates them from the burrowing bettongs," she said.

"The burrowing bettongs are slightly cuter, have a smaller nose, and they create little warrens and live in there in a little community with other bettongs."

Two images: the first is a black box shaped trap on the ground in torchlight, the second is a hand holding little balls of bait.
A trap and a bait, made of peanut butter, sardines and rolled oats, is used to capture the bettongs.(ABC Alice Springs: Victoria Ellis)

Ms Mulvena said the burrowing bettongs played an important role in the ecosystem by digging burrows that could be used as refuges by other species.

"Their diggings also help with vegetation growth," she said.

"The brush-tailed bettongs, they're not a digging species, but they help with spreading seeds and moving them around so new plants can pollinate in new places."

A small rodent being held with one hand looks at the camera from where it is bundled in fabric on the back of a ute.
Ms Mulvena says burrowing bettongs are cuter, with a smaller nose.(ABC Alice Springs: Victoria Ellis)

What's next for the species?

 Ms Mulvena said she had high hopes for the species when the bettong survey would be repeated in another 12 months.

"[I hope] they keep growing and keep sustaining themselves and keep staying at a good condition level," Ms Mulvena said.

Two people sit on the ground, their head torches cast a circular glow over a hand held ipad, their laps and an open toolbox.
It's hoped the bettong populations will continue to grow.(ABC Alice Springs: Victoria Ellis)

Mr Henderson agreed.

"Australia is the leading country in animal extinction, so it's really important that we aim to conserve these animals, especially these unique animals that are suffering catastrophic extinctions," he said.

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