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Recognisable by their distinctive tails – rust coloured at the top with a black and bushy end, the Red-tailed Phascogale is a carnivorous marsupial that lives off insects, spiders and small birds.
When the sun goes down at our Kojonup Reserve in south-west Western Australia, these tiny creatures spring into action, performing giant leaps between branches and trees.
Measuring 10cm in the body and weighing just 60g (about the weight of a chicken egg), they move at blink-and-you-miss-it speeds, leaping up to two metres in a single bound!
Once widespread through the southern half of Australia, surviving populations are mostly restricted to remnants of native vegetation throughout the wheatbelt region of WA.
Their preferred habitat is dense, mature forests of Wandoo (Eucalyptus wandoo) and Sheoak (Allocasuarina huegeliana), which provide tree hollows that phascogales line with grass and feathers for nesting.
In 2010 and 2011 populations were translocated from nature reserves managed by WA's Department of Biodiversity, Conservation and Attractions (DBCA) to our Kojonup Reserve, which provides fantastic Wandoo habitat sprawled across the 389-hectare property.
To support the translocation, 20 nest boxes (one per animal released) were set up at Kojonup and the animals transported directly into them, to give them a home-base to return to if faced with predators in unfamiliar surrounds.
The area is actively monitored with camera traps and regularly surveyed. During surveys we’ve often found many phascogales huddled in groups in their nests and we think they do this to keep warm.
We provide Alpaca wool in the artificial nest boxes, which is highly prized as boxes are raided for wool, which is often supplemented by feathers, bark, leaves and sticks.
Red-tailed Phascogales are nocturnal and live in trees. They can be more active in the day time if seeking food and will often move to the ground to feed on a wide range of small insects, spiders and small birds.
They’re territorial and the females will come back to the same nesting sites year after year, with three or four sites that they’ll use. Males move, on average, three to four times as far as females, with the greatest disparity during the July mating season. Home ranges vary from 1.5 ha to 8 ha.
As with some other small dasyurids (such as Brush-tailed Phascogales and antechinus), each year all males die within a month of mating.
Research suggests the stress of breeding season and the physiological changes males undergo results in fatal gastrointestinal ulcers (Bradley 1990). The physiological response is driven by free corticosteroid hormones that lead to immune suppression, haemorrhaging, infections and, eventually, death.
This male die-off is known scientifically as 'semelparity'. For species like phascogales, all males in the population die each year regardless of breeding success or resource availability. This probably evolved in response to highly synchronised, short breeding seasons (typically about two weeks, during predictable seasonal peaks of food abundance) in combination with intense sperm competition. Males trade off higher reproductive effort and, ideally, success against a lethal physiological cost.
While males can live up to 11 months, females can survive up to 36, reproducing two or three times.
The gestation period is 28 to 30 days, and while up to 13 young may be born, the maximum litter size that can be reared is eight (adult females have 8 nipples). Many marsupials employ this strategy. As marsupial young are born very early in their development, it's low cost to a female to produce extra young at that stage, which improves the likelihood that all eight teats will be found by offspring in the race from cloaca to teat.
From August to October young remain dependent on their mothers, but they’ll have weaned and dispersed to set up their own home ranges by the end of summer.
Red-tailed Phascogales are listed as nationally ’vulnerable’ under the EPBC (Environment Protection and Biodiversity Conservation) Act and considered Near Threatened by the International Union for the Conservation of Nature (IUCN). One of their primary threats is habitat loss and fragmentation from the widespread clearing of habitat for agriculture and development, and changed fire regimes.
Foxes are a threat when phascogales are active on the ground, but they can escape to the trees. Cats, however, are able to climb and can significantly impact on a population.
In 2010 our Ecologist Angela Sanders received a phone call from a colleague at the Western Australian Department of Parks and Wildlife who was looking for a place to translocate Red-tailed Phascogales.
Our Kojonup Reserve was a great candidate – it was part of their former range, it had Wandoo, it had Sheoak, plus we’d been controlling foxes for many years and no cats had been recorded on the reserve.
The idea was simple – moving a small proportion of a phascogale population from elsewhere in the wheatbelt and establishing a new, self-sustaining population on Kojonup.
Between 2010 and 2011 around 30 phascogales were released onto Kojonup Reserve just before their mating season. Trees were fitted with wool-lined boxes to allow safe nesting and to increase their chances of survival.
The results have been astounding. Recent surveys suggest they’ve started to spread out of Kojonup Reserve and into neighbouring bushland. The original 20 nest boxes have been added to, and there are now more than 60.
“We’ve been seeing more individuals every year since 2011,” said Angela. “Since these critters are short-lived, all of these would have been born at Kojonup, which indicates the phascogales are breeding – a wonderful sign."
– Angela Sanders, Ecologist"It’s really great habitat and it probably hasn’t had phascogales on here for 50 or 60 years, so it’s really good to put them back."
Climb up the tree. Open the nest box. And look inside...
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Bradley, A.J. (1990). Seasonal effects on the haematology and blood chemistry in the red-tailed phascogale, Phascogale calura (Marsupialia: Dasyuridae). Australian Journal of Zoology. 37:533-543.
