Sydney’s wild mammals

The Sydney region provides a range of habitats for native mammals, with over 70 species recorded. But, as elsewhere in Australia since European settlement, the number of native species has decreased while introduced species have increased.

For example, the Platypus once occurred in streams flowing to the Harbour but has now disappeared, and the diversity of marsupials, bats and native rodents has also diminished.

The reasons are not hard to find, with habitats in woodland, heath and wetland decimated by land clearance for urban expansion; herbivorous introduced species such as rabbits competing for food; and predatory cats, dogs and foxes capturing and eating the natives.

The good news is that despite these losses, Sydney is still home to a variety of fascinating mammals, some of which have adapted well to the urban environment. Others, however, maintain a tenuous presence and require conservation action to ensure their continued survival.

At the time of European settlement the Sydney region supported a diverse array of marsupials ranging in size from the Grey Kangaroo, Macropus giganteus, to the tiny Feathertail Gliders, Acrobates pygmaeus and Acrobates frontalis.

Thanks to the Australian Museum mammal collection, we have a permanent record of the former distribution of mammals in Sydney with representatives of at least 28 marsupial species from the mid-to-late 1800s and early 1900s.

Some species, like the Brush-tailed Rock-wallaby, Longnosed Potoroo, Yellow-bellied Glider and Brush-tailed Phascogale, have disappeared from the Sydney area but survive in bushland to the north and south of Sydney. Others, like the Koala, Squirrel Glider and Spotted-tailed Quoll can still be found in isolated pockets of suitable habitat around the city.

Two species, the Greater Glider and Dusky Antechinus, may even be making a modest comeback, having recently reappeared in Royal National Park after absences of more than 18 years and 40 years respectively.

Today the Common Brushtail Possum and the Common Ringtail Possum are the only marsupials that inhabit urban areas in reasonable numbers. They occupy remnant bushland, parks and many suburban backyards, where they feed on the leaves, flowers and fruits of native and introduced plants (including rosebuds, in the case of the ringtail).

Long-nosed Bandicoot

One fascinating species which was common around Sydney Harbour until the 1960s and early 1970s is the Long-nosed Bandicoot, Perameles nasuta. Museum records of this species span more than 130 years, dating back to 1878. The species maintains a tenuous presence, with two endangered populations: one at North Head, and the other (discovered in 2002) in Sydney’s Inner West. These small, disjunct colonies in the midst of a city of over 4 million people are remarkable. Long-nosed Bandicoots are also found in Sydney’s northern beaches and are common in the eastern parts of their range in New South Wales.

Eastern Quoll

The Eastern Quoll, Dasyurus viverrinus, is a beautiful, catsized marsupial carnivore with a particularly tragic history. It was recorded by Arthur Phillip in 1789 from Port Jackson and was known from a range of other localities around the Harbour, such as Concord, Drummoyne, Hunters Hill, Mosman, Rose Bay and even the grounds of Taronga Zoo.

A small colony survived in Neilson Park up until 1963 when a female quoll was killed by a car. The specimen, brought in to the Australian Museum, turned out to be the last known individual recorded from mainland Australia. Fortunately Eastern Quolls are still present in Tasmania and captive breeding colonies have been established with a view to returning this species to the mainland in future. This is timely given that recent studies have found Tasmanian populations appear to be undergoing a severe decline and the conservation status of this species in its last stronghold is no longer secure.

Bats are a group of native mammals still seen regularly around Sydney, in particular the Grey-headed Flying-fox, Pteropus poliocephalus. These large, sometimes noisy and much-maligned bats could, until as recently as January 2012, be seen roosting in large numbers in the Royal Botanic Gardens, a site they have occupied for more than a century.

Sadly (for some people), their numbers at this site have been greatly diminished by ongoing efforts to prevent them roosting there and damaging historic trees (although numbers at other roosting sites have increased accordingly).

Another smaller species of flying fox, the Little Red Flying-fox, Pteropus scapulatus, is also present in Sydney during some years, as is the larger Black Flying-fox, Pteropus alecto, which appears to be spreading south in response to climate change.

At least 20 different species of ‘micro-bats’ (small, mostly insectivorous bats) have also been recorded from the Sydney region over the last 120 years, although several species are likely to have disappeared from their inner city roosts.

The Australian Museum Mammal database reveals a number of past urban hotspots for micro-bats. All Saints Church at Hunters Hill has been a popular roosting site for a number of species, including the East-coast Freetailedbat, Micronomus norfolkensis, and the Eastern Broadnosed Bat, Scotorepens orion. Other areas where bats and humans have coexisted are the cellars of Elizabeth Bay House, the North Sydney railway tunnel and the Balmain power station.

The majority of Sydney’s bat species, however, depend on the surrounding native forests and woodlands for crucial feeding and roosting sites. Most species roost under bark or in tree hollows, and the loss of urban bushland would result in their disappearance from the Sydney region. ‘Bat boxes’ erected in suburban backyards can provide supplementary roosting sites for micro-bats and provide an opportunity to get a closer glimpse of some species.

Five native species of rodent survive in Sydney and its environs. One, the Water-rat, Hydromys chrysogaster, lives in and around the Harbour, while other more cryptic species inhabit native forest, woodland and heath to the north and south of the city. In 2011 researchers at Sydney University began releasing native Bush Rats, Rattus fuscipes, at several sites in Sydney Harbour National Park in an effort to reestablish populations there.

Water-rats
The Water-rat is an attractive, shy and unique species of native rodent that was once recorded from many localities around the Harbour and along the Parramatta River. Water-rats are large rodents that are superbly adapted to aquatic life. They have webbed feet, sleek dense fur, small ears and strong whiskers that enable them to detect invertebrates such as mussels and crabs, even in the murkiest of waters.

Specimens of Water-rat in the Museum’s collections date back to 1879 when they were apparently common in places such as Hunters Hill, Point Piper, Elizabeth Bay, the Botanic Gardens and further up-river near Gladesville. Water-rats seem to have disappeared from many parts of the Harbour but can still sometimes be seen around the foreshores of Manly and Rose Bay, Clarke Island, Sisters Bay and Goat Island (ironically, where the TV cop series Water Rats was filmed).

Having such a relatively little-known species of native mammal in the midst of Sydney creates a marvellous opportunity for scientific researchers to learn more about the ecology and genetics of this relatively cryptic species.

Introductions
Three species of rodent were inadvertently introduced during the early days of European settlement and are now well established. They are the Black Rat, Rattus rattus, Brown Rat, Rattus norvegicus and House Mouse, Mus domesticus. The Black Rat (the name is misleading as it is generally grey-brown) is frequently encountered in backyards and roofs as well as in urban bushland. Young animals are often mistaken for native species as they are relatively attractive with soft fur and large rounded ears. However, this species is distinguished by its long tail (longer than the body) and excellent climbing ability.

TO THE FUTURE

A review of the marine mammal fauna of the Sydney region deserves an article of its own, with various species of whale, dolphin and seal seemingly making a comeback. Yet across New South Wales, 26 species of native mammal have disappeared since European settlement, and nine of these are now extinct everywhere. We are fortunate to co-exist with the remaining species, but their survival depends on our continued vigilance.