Victorian Eastern quoll specimens

Overview

The Eastern quoll has not been confirmed on mainland Australia since 1963 when the last one died in Sydney, NSW. Prior to this the species' distribution extended from south-east South Australia, through most of Victoria, along the eastern seaboard of New South Wales and possibly into south-east Queensland.

In September 2008 Museum Victoria released an article describing two Eastern quoll specimens which had been collected as roadkill near Mount Rothwell Conservation and Research Centre, west of Melbourne.

Now, with the sanctuary's permission, Where Light Meets Dark would like to report two further Eastern quolls discovered in the same vicinity in 2005.

Mt Rothwell Sanctuary

Mt Rothwell sanctuary is a 45 minute car trip west of Melbourne. It has been designed as a "feral-proof enclosure", keeping predator species such as foxes, cats and dogs away from the endangered species that live within its boundaries. The sanctuary's first Eastern quoll breeding season was in 2002 and 50 young were produced.

Eastern quolls were released into the sanctuary from 2002 through to 2006. All captive-bred Eastern quolls during this time were tagged with microchips. As Eastern quolls are able to breed in their first year, the first "wild born" quolls (within the sanctuary) would have arrived in 2003 and these would not have received microchips.

In 2005 the sanctuary sold a 200 acre portion of the property. Trapping was undertaken over several weeks in order to attempt to remove as much of the endangered wildlife as possible, however there remains the possibility that not all quolls were removed. The two specimens which were discovered deceased outside the sanctuary in that year, were found after the exchange of the land.

In addition to the Eastern quolls, Mt Rothwell has had significant success breeding the critically endangered Eastern barred bandicoot. It is also home to red-bellied pademelons (now extinct in the wild on the mainland), brush-tailed rock wallabies (critically endangered in Victoria), long-nosed potoroos (vulnerable), spotted-tailed quolls (endangered) and rufous bettongs (extinct in Victoria).

2008 Specimens

(Photo of 2008 mainland Eastern quoll specimen from the Museum Victoria source article, where it is credited as "Image: Marilyn Blankley Source: Rayleen Reynolds")

Two dead Eastern quolls were collected in 2008 - one in June and the other in September. Both were found by local wildlife carer Raylene Reynolds and forwarded to Museum Victoria. Ms Reynolds reported having seen quolls feeding beside the road previously, where these two specimens were found. The location is also close to where one Eastern quoll was found in 2005.

Museum Victoria's news article on the mainland Eastern quolls raises a number of interesting questions. It is almost certain the quolls are connected with the sanctuary in some way - either as direct escapees, or the descendants of escapees.

If these are descendants then how long have Eastern quolls survived outside the sanctuary? Have they developed specific adaptive behaviours to cope with their environment? Have they interacted with predators, and in particular foxes? (The red fox, Vulpes vulpes has recently been introduced into the island state of Tasmania - the Eastern quoll's last stronghold - and may have contributed to their extinction on the mainland.)

The Museum proposes that an examination of the specimens' stomach contents may reveal more information about the inter-specific interactions it may have had. Genetic analysis may reveal more about the proximity of the relationship between these quolls and the sanctuary's.

2005 Specimens

Two dead Eastern quolls were also collected outside the sanctuary in 2005. The one pictured here was found as roadkill, near the same location as those recovered in 2008. The second was discovered drowned in an outdoor bath tub. (The property owner now places a branch in such water-stores so that any small mammal which falls in has an escape route.)

In many respects these two quolls pose even more questions than the recent specimens. To begin with, both were black.

By 2006, Mt Rothwell manager Paul Mervin estimates over 500 Eastern quolls had born in captivity across all mainland sanctuaries breeding Eastern quolls. Without exception, all captive-bred Eastern quolls were the more common fawn colour despite some sanctuaries even pairing two black quolls together.

In the wild in Tasmania, about 10 percent of Eastern quolls are black. Using this ratio, mainland breeders should have expected approximately 50 of the 500 captive-born mainland young to be the black form.

If the 2005 specimens were escapees, or descendants of escapees (possibly freed through the land sale), then is there something about the captive husbandry of the species - even on a 200 acre free-range property - which inhibits the expression of the black form? If not, then why were no black quolls produced in 5 years? Could these two quolls possibly have really been surviving mainland stock - from a remnant population far removed from expected habitat? If so, then they may have been attracted to the sanctuary because of the captive quolls - but this really is the most unlikely scenario.

Finally, could the 2008 specimens have come from a population which has survived outside the sanctuary since 2005?

It is doubtful we will ever have answers to most of these questions and with Eastern quoll sighting reports being forwarded to WLMD from a number of locations in NSW, there may well be other populations persisting in small pockets of wilderness.

Credits