General information

Kangaroos are marsupials and belong to the Family Macropodidae (i.e. big feet) that is grouped with the Potoroidae (potoroos, bettongs, rat-kangaroos) and Hypsiprymnodontidae (musky rat-kangaroo) in the Super-Family, Macropodoidea. This comprises around 50 species in Australia and a dozen or more in New Guinea.  Some of the smaller species, such as Yellow-footed Rock-Wallabies, Burrowing Bettongs, accompanied Pig-footed and Golden Bandicoots, Bilbies and possibly Hairy-nosed Wombats into extinction with the advent of pastoralism. However, the largest species remain in much of their original range with the grey kangaroos expanding inland as grazing habitat increased and coastal habitat was lost in clearance for agriculture. The defining feature of the kangaroo family is that they are the largest vertebrates to hop (both currently and from what we know from palaeontology).

The genus Macropus includes not only the large kangaroos but a range of mid-sized macropods known collectively at wallabies or brush wallabies. The exception is the Swamp Wallaby which is in its own genus Wallabia by virtue of its different chromosome number and other features. With the advent of agriculture and pastoralism the wallabies have fared less well than the kangaroos with most species in reduced ranges since European settlement. One species, the Toolache Wallaby (Macropus greyi) is extinct. In this pattern of range contraction, the Swamp Wallaby, is again an exception as it remains reasonably abundant in many peri-urban parks and reserves.

The Wallabies like the larger Kangaroos are predominantly grazers but may take some browse, especially the Swamp Wallaby. They share a similar body form and habits to the larger Kangaroos and are sympatric with Grey Kangaroos or the Antilopine Wallaroo in the north.

Species

Swamp Wallaby

Wallabia bicolor ('two-coloured wallaby')

Best place to see

Mornington Peninsula National Park, Victoria

Mornington Peninsula National Park is 90 km south-east of Melbourne. The area is thus close to a large city and major tourism hub and is popular for a range of leisure activities including the food and beverages of the many wineries on the Peninsula. Both the Swamp Wallaby and the Eastern Grey Kangaroo are readily seen in this Park but the former is much more cryptic. The Park conserves a variety of native vegetation types including coastal dune scrub and grassy forests, Banksia woodlands, coastal heath lands, heath woodlands, riparian forests, and swamps. You might expect the Swamp Wallaby to favour the swamps but the common name is something of a misnomer and this species is a generalist in terms of habitat selection provided there is some dense cover to shelter in such as may be found around the margins of a swamp. Greens Bush and the Highfield area of the Park are recommended for viewing macropods. The park has a diverse fauna that include 32 mammal species and 167 bird species.

The Park does not allow camping but there is a wide range of accommodation including camping in the numerous nearby towns. The lighthouse keeper's quarters at the Cape Schanck Lighthouse. can be booked for a stay.

Identification

The Swamp Wallaby is not a member of the same genus as the other Brush Wallabies due to a number of features in its morphology, genetics and behaviour. For example, the chromosome number in Macropus is 16 but 11 in male Swamp Wallabies and 10 in female Swamp Wallabies. The Swamp Wallaby is the sole surviving member of its genus Wallabia  and bears a distant relationship to Macropus. The specific name bicolor refers to the marked difference between the back fur which is dark brown to black and the belly fur which is yellow to a strong reddish orange. A light yellow to light brown cheek stripe is faint in its southern range and distinct in the north. The paws, feet and tail are dark through to black but the tail tip may be white in the northern range. The tail is long and held straight out behind the body when hopping and the general gait is to keep the head low to the ground. The long black tail and overall dark colouration has possibly lead to false sightings of 'panthers' in the Australian bush as the Swamp Wallaby's hindquarters disappear into dense cover.

 

Males are larger reaching 21 kg than females reaching 15 kg.

 

Habitat

The Swamp Wallaby has a remarkably broad latitudinal range extending from Victoria to North Queensland in a largely coastal distribution but it can be found well out into Western NSW. Along the east coast of Australia, it is present in a broad gradient of habitat and shares this generalist characteristic with the Red-necked Wallaby. The two species are largely separated by the Red-necked Wallaby's preference for the ecotone between dense and open vegetation and the Swamp Wallaby's preference for dense vegetation in forest, woodland, Brigalow scrub and heath. It gets its common name "Swamp" from often associating with moist patches of vegetation with dense grasses and ferns. For example, in logged forest in south-eastern NSW Swamp Wallabies persisted in gullies with high projective shrub cover.

 

The Swamp Wallaby appears to have resisted the advance of agriculture and pastoralism better than most of the Brush Wallabies. It generalist habitat use, ability to browse and graze and its cryptic nature have contributed to this adaptability. However, browsing tree-seedlings and shrubs has brought it into conflict with forestry and horticulture. Where suitable habitat persists, the Swamp Wallaby is at home in the peri-urban environment and this makes it vulnerable to dog attacks and roadkill.

Foraging behaviour

The diet of Swamp Wallabies has been studied in several localities. In north-eastern NSW they ate forbs, ferns, shrubs, a combination of grasses, sedges and rushes, and fungi in similar proportions. There were also some vines in the diet. The species is a generalist feeder and takes significant browse. An interesting component is hypogeous (under-ground fruiting) component which formed around 30 % of the diet in a burnt Victorian site. Mycophagy (fungus eating) is normally associated with the much smaller potoroos and bettongs. On North Stradbroke Island in Queensland the diet again comprised shrubs, forbs, grasses, ferns and fungi.

 

Home ranges are around 16 ha and overlap amongst individuals. Typically there is a shelter site in a densely vegetated gully and the Swamp Wallabies emerge to feed on more open patches of vegetation and on the margins of pasture.

Reproductive behaviour

The reproductive biology of the Swamp Wallaby is atypical of the patterns found in the Brush Wallabies. The Swamp Wallaby has a pre-partum not post-partum oestrus as the gestation period (36 d) is longer than the oestrous period (31 d). It does have a period of lactationally controlled embryonic diapause consistent for the Brush Wallabies. Breeding is not seasonal and births occur in all months of the year.

 

The Swamp Wallaby is usually seen alone or with a young-at-foot. Even so home ranges overlap and males may check females and mate with receptive ones when they emerge to common foraging areas rather than seeking them out in daytime shelter. This potentially leads to male-male competition which is likely resolved by short kicking attacks on each other with the larger individual emerging as the winner.

Social organisation

The Swamp Wallaby is a solitary species but loose aggregations may occur on favoured foraging areas. These are likely to be the places where the sexes interact. Home ranges overlap but have an individual rather than shared core centred on dense shelter often associated with moist vegetation.

Further readings

Ben-Ami D, Ramp D (2006) The effect of road-based fatalities on the viability of a peri-urban swamp wallaby population. Journal of Wildlife Management 70, 1615-1624.

Claridge AW, Trappe JM, Claridge DL (2001) Mycophagy by the swamp wallaby (Wallabia bicolor). Wildlife Research 28, 643-645.

Di Stefano J, Anson JA, York A, Greenfield A, Coulson G, Berman A, Bladen M (2007) Interactions between timber harvesting and swamp wallabies (Wallabia bicolor): Space use, density and browsing impact. Forest Ecology And Management 253, 128-137.

Hollis CJ, Robertshaw JD, Harden RH (1986) Ecology of the swamp wallaby(Wallabia bicolor) in north-eastern New South Wales. I. Diet. Australian Wildlife Research 13, 355-365.

Osawa R (1990) Feeding strategies of the swamp wallaby, Wallabia bicolor, on North Stradbroke Island, Queensland. I. Composition of diets. Australian Wildlife Research 17, 615-621.

Paplinska JZ, Moyle RL, Temple SPD, Renfree MB (2006) Reproduction in female swamp wallabies, Wallabia bicolor. Reproduction Fertility And Development 18, 735-743.