Camera trapping for Northern Bettongs at Yourka Reserve

about  Yourka 
on 25 Mar 2015 

Not even an impeding cyclone nor freezing creek crossings could put off the intrepid camera trappers at Yourka Reserve last week. Bush Heritage staff Paul Hales (Reserve Manager), Allana Brown (Healthy Landscape Manager and Ecologist) and volunteer Robert Goodwill teamed up with WWF’s Jess Koleck to establish 19 camera traps around Yourka’s most inaccessible ridge lines.

Northern bettongs (Bettonga tropica) are a small species of nocturnal, solitary macropod with adults weighing in at around 1.2kg. During the day, they are excellent at hiding themselves away in grass nests they construct out of materials gathered with their tails, waiting for night to fall before emerging to dig for truffles (hypogeous fungi) and the stem bases of cockatoo grass. Because of this highly specialised diet they're limited to the tall, wet eucalypt woodlands that can produce enough truffles throughout the year. Unfortunately in north Queensland this habitat is highly fragmented; found as narrow strips within an area less than 500 square kilometres.

Through this Australian Government funded project, WWF is working with local stakeholders throughout the region to gain a better understanding of this endangered marsupial. The camera trapping at Yourka is the first recent serious survey effort undertaken to ascertain the distribution of this highly endangered species beyond the known populations around the Lamb Range.

The team used all-terrain buggies to explore suitable habitat, looking for abundant cockatoo grass as well as a mix of Xanthorrhoea (grass trees), mature Eucalyptus tereticornis and Corymbia citriodora (blue gum and lemon-scented gum). There have been whispered rumours of possible northern bettong sightings at Yourka, however limited spotlight surveys have not yet turned up any proof. 

So you can imagine our excitement when Jess discovered the first possible sign of bettongs — the distinctive shallow digging with a shoot of cockatoo grass growing out of it. Bettongs dig up the grass to find the enlarged base to chew on, but often miss small parts of the root which result in a new shoot.

Soon after Paul spotted an even better sign. Although appearing like nothing but dried grass to the eyes of most, this evidence was in fact a bettong spit-ball, known as an oort. Oorts are made once the bettong has had its fill of the tasty cockatoo grass juice and it spits out a ball of dry grass-fibres.

James Cook University will do DNA analysis of the oort to allow us to identify whether this has come from a Northern Bettong or the more common Rufous Bettong, which are known to occur at Yourka (in fact, we see these cousins regularly around the shed).

Although our hopes are high for some northern bettongs, these camera traps will undoubtedly also provide information about other species that occur on the reserve. Our plan is to leave them out for five weeks before returning to analyse the photos. We’ll keep you posted on the results!