Tropical Topics An interpretive newsletter for the tourism industry Feral and introduced animals No. 25 January 1995 Foxes at the door Notes from the European red foxes (Vulpes vulpes) were released in Victoria in the 1840s-70s Editor for sport hunting. They spread rapidly over most of the continent, following introduced rabbits, reaching Queensland by the 1900s. They were first recorded at Longreach in 1920, and by 1933 had moved north by 400km. There are two main types of animal pest in Australia, feral animals -- domestic livestock or pets which Until recently it was thought that Elsewhere in Australia, foxes have have gone wild -- and introduced north Queensland would remain free of been implicated in the decline of at wild animals -- which were foxes -- that they did not thrive in a least 19 native mammals and the deliberately or accidentally set free tropical climate and environment. extinction of at least two, possibly in the Australian environment. However, as rabbits have been nine. A further 30 are considered at Sometimes this was for sport (foxes, increasing in numbers in the risk. Although habitat clearing remains rabbits), as an attempt at biological Ravenshoe/Herberton/Atherton area the main reason for the decline of control (cane toads, mynahs), in the last few years, so too have foxes native species, foxes may be the factor accident or thoughtlessness (fish, been appearing. In 1993 two road- which tips a reduced population rats, birds) or simply because killed foxes were discovered between towards extinction. Certainly, where people thought they would make a Mareeba and Kuranda and they have they have been excluded, endangered pleasant addition to the Australian now been sighted at Laura and Mt animals, such as rock wallabies in countryside (birds, deer). Carbine. Western Australia, have made a good recovery. Not all creatures introduced by Foxes prefer open country and are not people have been successful. A found in rainforest. It seems, therefore, With their additional potential as number of birds were released and that they have been circling around rabies carriers, should this disease never seen again. Certain the wet tropics, hunting along ever reach Australia, foxes are a characteristics, however, made rainforest margins, including wet priority for control measures. some of the introductions into pests scleropyll forests, and taking -- rapid breeding, few or no natural advantage of areas cleared predators and diseases, adaptability of forest by people. and a talent for thriving when others are in difficulty (foxes do well For this reason, foxes may during times of drought). pose a major threat to Illustration courtesy Rural Lands Protection Board northern bettongs Most pests have been greatly (Bettongia tropica) which assisted in their invasion of the exist only in a few small continent by the activities of pockets uncomfortably close people. Foxes and feral cats have a to recent fox sightings. Other ready food source in the introduced wet tropic animals at risk from rabbits, rats and mice. Rainforest, foxes include rufous bettongs, which is avoided by most pest bandicoots, wallabies, animals, becomes vulnerable when phascogales, quolls, planigales, openings are cleared for them to tree-rats and various other make their way in. marsupial mice and rodents in drier tropical woodland, as well as ground birds. Apart from direct predation, foxes also tend to outcompete native carnivores for food. Controlling the pigs It is almost certainly impossible to eliminate feral pigs from Australia. There are too many, they are widespread and they are too clever (they are more intelligent than dogs.) Local eradication in sensitive areas, such as rare and endangered species habitat, is the best we can hope for. Under the Lands Protection Act every landholder and land manager is responsible for the pigs on their land. Hunting, poisoning and trapping are all effective control methods, but when the pigs are scattered throughout inaccessible forests it is impossible to target enough of them at one time. Poisoning and hunting, especially with dogs, endanger native species, so trapping is seen as the best option, from the point of view of efficiency and environmental sensitivity. Copyright NSW National Parks and Wildlife Pigs move in and out of the rainforest. A pig cannot go longer than four hours Service. Illustration by without water and a sow with young must stay almost permanently by water. In Gavin Gatenby. the dry season large numbers concentrate around water holes on the coastal plains. Pigs also need cover, disliking the open. By day they may hide in the forest, especially when the cane is too short to cover them, coming out at night. The plus side of pigs The most efficient way of trapping them seems to be to catch them as they move between the coastal areas and the forested ranges. Reducing populations on the Since it is impossible to eradicate fringes should both reduce damage to agriculture in these areas and control these animals, it has been numbers within the World Heritage Area. suggested that they be seen as a resource instead. In fact, it has Pig traps been pointed out that when sheep prices are low it would make more Over the last two years the Wet Tropics Management Authority has purchased economic sense to kill the sheep $50 000 of materials to build 200 large traps. These have been issued to various and feed them to the feral pigs! organisations who have contracted 14 professional trappers to operate them. Australia is now the world's These trappers have killed over 1 000 pigs this year. Additional numbers have biggest exporter of wild pig meat been trapped by several Aboriginal Corporations, DEH and Forestry staff and for human consumption as game Cassowary Protection groups. meat. The 120 000 pigs exported annually to European markets earn The most successful method involves providing free food for the pigs for some foreign revenue of up to $20 time before the trap is set. Numbers of pigs increase as news gets around the local million, more than from the population and then one night, when they are all at the party, the gate shuts! commercial pork industry. Thus a valuable industry has the added The traps are set at night to avoid catching cassowaries but the accidental bonus of cutting down numbers of trapping of native wildlife is a concern. Recently farmers from Mission Beach, in feral animals. conjunction with the Wet Tropics Management Authority and the local Community for Coastal and Cassowary Conservation (C4), designed a wildlife- Aboriginal people complain that proof trap based on observations of pig foraging. A metal trigger bar is placed in feral pigs have damaged many of front of the food. The pig reaches under this bar and then, in the process of their traditional food sources, such eating, throws its head up, hitting the bar. This causes the door of the trap to as yams. However, the pig itself shut. If cassowaries and other animals enter the trap, they simply reach over the has become an important food bar and are not caught. In its first year the trap has caught 55 pigs on three farms source for many remote -- and no other animals. More are being manufactured. Called the trailer trap, it communities. Provision of mobile can be transported to where the pigs are. Despite this success not all pigs will be abattoirs could enable those outwitted. A number of these very intelligent animals will communities to earn a good income never go near traps. from the game meat industry, while Controlling the cats also participating in feral pig control. In addition, if trained in It is impossible to eradicate feral cats Responsible cat identifying disease symptoms, they except on islands where trapping ownership could give early warning of an baiting and shooting can be effective. involves: outbreak of problems such as foot These methods are also worth using · keeping cats and mouth disease. in specific habitats of endangered indoors, in the Illustration by John Allison species. A biological control is the house, a shed or special outdoor run, only long-term possibility. At the particularly at night. Cats kept at home Control complications moment CSIRO scientists are live much longer. attempting to use a modified virus to · identifying cats by microchips, collar Control of feral animals is not a immunise foxes against their own and tags or tattoos. simple matter of concentrating on sperm or eggs, effectively sterilising · limiting the number of cats kept. one at a time. A certain balance is them. This method could possibly be · desexing all cats not used for maintained between all these used eventually for feral cats. commercial breeding. unwanted introductions. If foxes · providing adequate food so cats will and cats are eliminated, rabbit In the meantime, responsible cat not hunt due to hunger. populations will explode, ownership is one way to reduce the · attaching two or more bells to their competing with native animals. On cat problem. Straying and dumped collars. Though not very effective this the other hand, if only rabbit cats quickly become feral, restocking may give potential victims some numbers are reduced, foxes and areas where eradication programs warning. cats will prey even more heavily have been carried out. · never dumping cats in the bush. on native wildlife. 2 Nature notes A diary of natural events creates a pleasing journal which grows richer with the passage of time. Watching for the recurrence of an event after noting it in a previous year, and trying to understand what could have caused changes in timing, is intriguing. These notes are from the author's own notebook, or were offered by researchers and fellow naturalists. Readers will, inevitably, note variations between their observations and those appearing here. If you do not keep a nature diary perhaps this will inspire you to begin one. While some plants put on flowers quite dependably over a short period each year and others may flower sporadically at intervals of many years, there are some species which carry a few flowers in many months of each year. Two plants which often reward a Fruit from a member of the search for flowers are both members of persimmon family in northern the family Celastraceae. Neither is rare rainforests should be on show in suitable habitat, but they are still during the summer months. Scrub without common names. ebony, as it is known, produces a red to orange fruit. It is set on a robust green calyx comprised of four prominent star-like sepals joined at the base. At a diameter of up to 40mm, this A related plant is Hedraianthera Diospyros hebecarpa fruit is larger porphyropetala, a small shrub or tree than any other wet tropics persimmon, which produces delicate, five-petalled although a long way short of the flowers varying in hue from white to luscious cultivated fruit. pink to purple. The flowers are carried on fine stalks about 2-3cm long, which grow into thick woody stems bearing a stubby fruit if pollination has been successful. The hard-surfaced fruit splits into five component lobes which scatter shiny brown seeds ornamented with only a small, pale aril. These seeds seem to fall unnoticed to the earth, quite unlike those of Hypsophila which are plucked and dispersed soon after they go on show. Hedraianthera Hypsophila dielsiana is an allusion to the almost stalkless has bright red flowers, a anthers described as growing like ivy little over 0.5cm across, clinging to a wall! carried on long, slender flower stalks. Fruits borne Summer beside rainforest streams or from successful flowers rivers will often yield sightings of two look rather like gherkins, lovely butterflies attracted to damp hanging from surprisingly thin stalks. Those who give attention to the leaves or still pools. The orange and After quite a long maturation period summer skies above open fields, black male cruiser will often allow these `gherkins' split open revealing particularly in February, may be quite a close approach, making it seeds encased in bright orange arils rewarded by the song of an inspiring possible to take photographs at which are soon devoured by birds. bird known as the singing bushlark. distances of about a metre. Male The name Hypsophila is derived from Widespread in Australia and common cruisers sometimes alight on bright the Greek hypsos, meaning high, and in many parts of the wet tropics, this orange flagging tape such as that used philos, loving, an allusion to the little bird is seldom noticed except by bushwalkers. Cruiser females are montane habitats preferred by some when it lifts into the air on display markedly different in appearance, species of this genus. flights during the breeding season. showing more colours and yet not The singing bushlark flies a long way looking as brilliant. The blue triangle up, circling and hovering while putting (above) is an even more prominent out a stream of melody and mimicry, streamside butterfly on hot summer sometimes for as long as 40 minutes. mornings, the males being not only One of the delights of a bright approachable but often flying to summer's night is to hear the clear people wearing a colour comparable to song of this little bird long after dark. the sky blue of their wings. 3 Ferals and pests in the Wet Tropics Pigs While most feral pigs originated from European domestic stock, some may have been introduced from Melanesia and China. Now an estimated 12 million of them roam Australia, 3 million of them in Queensland. Pigs are considered a major agricultural and environmental pest. It is calculated that they do over $70 million agricultural damage annually, eating and trampling crops and damaging fences and roads. Omnivores, they kill and eat up to 40% of newborn lambs in some areas. There is also great concern about their potential to carry foot and mouth disease, estimated to cost at least $9 billion in the first year if it gets into Cane toads Australia. The introduction of the South American cane toad (Bufo marinus) represents a Pig damage is evident in the environment. They dig up large areas, eat roots and spectacular failure of a biological control trample saplings, rub and ringbark trees, erode stream banks, muddy and contaminate method. In 1935, 102 toads were imported to water. Weeds thrive in areas disturbed by pigs, possibly having been carried there on Gordonvale and bred in a research station. the coats or in the stomachs of the animals. They can carry many diseases, including By 1937, 62 000 toadlets had been released forest dieback (phytophora). in the hope that they would eat their way through the swarms of beetles consuming Pigs prey on native wildlife, consuming large numbers of soil fauna, such as the sugar cane. earthworms and beetles. Feathers, fur and mammal bones have been found in their stomachs but it is uncertain whether these animals are killed or eaten as carrion. Unfortunately beetles can fly but toads (Other pigs' toenails have also turned up -- evidence of cannibalism.) They eat the can't -- plus the toads didn't like the cane eggs of ground nesting birds, such as the brush turkey, as well as eggs of sea turtles. fields. The insects were finally brought On at least one occasion strong evidence points under control by applications of chemicals to predation of cassowary chicks and they -- while the cane toads continued to certainly compete with these spread, well out of control. They have now birds for forest fruits, the pigs' colonised most of Queensland and are digestive systems probably advancing into the Northern Territory at the destroying the seeds which rate of 27km a year. They are a menace to the cassowaries distribute so the environment, gobbling up insects, other effectively. Pigs are also frogs, small mammals and reptiles, and responsible for attracting poisoning anything which tries to eat them. hunters, who often bring Their eggs and tadpoles are toxic, a threat to badly-controlled dogs, into other aquatic creatures. CSIRO researchers environmentally sensitive areas. are now studying their native environment (For information on pig control, in South America, in the hope that they will see page 2) discover a control which can be applied to Pig and rabbit illustrations courtesy Rural Lands Protection Board Australian populations. Rabbits Introduced birds Like foxes, rabbits were introduced for As many as 20 species of birds have been introduced to Australia. Many were imported sport in 1859. Their numbers have been by early settlers who wanted familiar animals around them in their new home and increasing in the Ravenshoe/Herberton/ Acclimatization Societies which deliberately set free all sorts of exotic fauna and flora. Atherton region in the past few years and have even been spotted well within the Many introduced birds originally escaped from captivity. The rainforest, although it is not anticipated nutmeg mannikin (spice finch) spread rapidly once it that they would move into this became established in Brisbane in the 1930s to become one environment in any numbers. of the most abundant birds on east coast Australia. Breeding all year round and eating seeds of almost any grass and Apart from attracting foxes, rabbits are herb, it is a major threat to native finches in tropical very damaging to the environment. They grasslands. compete for food with pademelons, wallabies, rufous bettongs and anything The common myna (right), a native of India, was introduced else that eats grass (including cattle). to north Queensland cane fields in 1883 in the hope that it They also change the habitat for animals would control insect pests. Sometimes referred to as flying such as the northern bettong. Many rats, mynas now compete successfully with native animals suffer from reduced cover which birds for food and, even worse, for nesting sites in also means reduced food supplies for holes. insectivorous mammals such as planigales and phascogales. Rats and mice The black and brown rats and the house mouse probably arrived with the First Fleet -- or even earlier on the ships of previous seafarers. They benefit from human habitation and crops. The black rat can carry serious diseases such as plague, leptospirosis (Weil's disease) -- a problem in cane fields -- and salmonella poisoning. Rats can also cause fires by chewing electrical insulation and they have been blamed for damage to seabird colonies. Plagues of mice can create huge amounts of damage to grain crops. 4 Cats Cats are the most widespread pest in Australia, occupying almost every environment -- although they tend to avoid undisturbed rainforest. Some are domestic while many more are Cartoon by Patrick Cookİ Australian Nature Conservation Agency ferals, not relying on human contact. Both types are hunters. An average feral cat weighs 4kg (they are larger than domestic ones). It needs to eat 5-8% of its body weight, the equivalent of ten small animals each day or 3 600 each year. If only 1 000 of these are native animals, it is possible that the estimated 12 million feral cats kill an appalling 12 000 million native animals a year. The 3 million or so domestic cats take their toll as well. Surveys have shown that the average well-fed cat brings home 30 vertebrate animals a year. This adds up to almost 90 million vertebrates, probably 75 million of them native, killed annually by domestic cats. This is almost certainly an underestimate, since not all prey is brought home and not all domestic cats are as well-fed as those in the surveys. While rabbits, mice and other introduced species are among the species taken by cats they have been known to kill and eat more than 186 species of native birds as well as 64 mammal, 87 reptile, ten frog and numerous invertebrate species. They also compete directly with native carnivores for food and dens and transmit diseases, such as toxoplasmosis which is generally fatal to marsupials. Like foxes, cats have the potential to spread rabies. (For information on cat control, see page 2.) Ants Earthworms Geckos Along with many more foreign insects, a Originally a resident of Brazil, number of species of ants have somehow At least two species of these little lizards Pontoscolox corethrurus, an been introduced to Australia. The brown have arrived here from S.E. Asia, almost earthworm, has successfully Argentine ant is a common household pest. certainly with people. One is established itself throughout the parthenogenic, meaning that the female tropics. These worms may have Another introduced can produce young without any male arrived attached to equipment used ant is ousting the involvement. This assists greatly in their during the gold rushes or in potted native species from ant dispersal since just one individual is plants. Certainly they were well plants (left) -- those needed to begin a new population. established by 1913. Occurring in very peculiar epiphytes large numbers they have been moving which accommodate The introduced species, as well as one of into disturbed rainforest along ants in special our native forest geckos, make walking tracks, roads and streams. At passages in the themselves at home in our houses. While this point it is not known if the structure of the plant, looking very similar, the loud chattering invaders compete with and/or trading shelter for food supplies. The ant calls of the more recent arrivals displace native worms but natives are plants, however, are not thriving with their distinguish them from the native species rarely found where the newcomers new tenants. The seeds do not set as well which produce only a soft scolding. It is have become established. Native and the caterpillars of the Apollo jewel possible that the newcomers may worms are important for breaking butterfly, which are normally tended by the compete with the native geckos for food down and recycling nutrients from traditional residents of the ant plant, are and space. dead wood, a task which Pontoscolox being neglected. (See Tropical Topics 13.) does not perform. It doesn't aerate the People soil either and it may carry diseases. Many wet tropics worm species are While most of these animals have arrived in Australia naturally, found nowhere else. It would be a some were released or escaped from captivity in the Sydney area in great pity to lose them before they the late eighteenth century. They are, without doubt, the most have even been adequately studied. destructive of the introduced species, having extensively damaged the environment when building their shelters and in their quest for food. They are also responsible for introducing all pest species to the continent. Freshie crocs Although native to some parts of tropical Australia, freshwater crocodiles do not occur naturally in the wet tropics. However, they have been turning up in freshwater lakes and streams, both on the coast and tablelands. There are at least two in Lake Eacham and one in Lake Tinaroo. Probably people have picked them up (illegally) from the wild and have subsequently dumped them when they became too large to keep as pets. Animals (and plants) artificially transferred from one part of Australia to another can be just as destructive as imported pests. In the case of freshwater crocodiles they probably pose a threat to platypus and other aquatic life. 5 Facts and Stats Questions & Answers on pests these hungry animals thus allowing Q Why do some trees fruit on the Foxes are the largest mainland some to survive and produce the trunks? predators next to dingoes and feral next generation of plants. dogs. Apart from their main prey, A Cauliflory, as the habit of rabbits, they feed on other small Q How did the Great Barrier Reef flowering and fruiting on the trunk is mammals, carrion and even insects and survive the Ice Ages? wild fruits. termed, is a characteristic feature of tropical rainforests. Rather than risk A researcher tracking radio-collared A In the course of continental flowers and fruit being hidden from ringtail possums north of Sydney movements the northern tip of potential pollinators and dispersers in discovered that 45% fell prey to foxes Australia reached the warm waters of the dense canopy, producing them in while native predators took only 5%. the tropics about 17 million years the relatively open understorey may ago. Coral larvae from the Pacific be a better advertising strategy for A female cat can have three litters, coral reefs began to colonise the some species. As many rainforest averaging five kittens each, in a year. shores where water was shallow. species flower and fruit only If one female produces four female occasionally, visibility is especially kittens a year she could, in ten years, During the Ice Ages sea levels fell as have nearly 2 million female important at that time. A study of descendants. the climate cooled and more water bumpy satinash, Syzygium was trapped in the ice caps. Some cormiflorum, has shown that the In a `good year' a female pig can have corals were left high and dry and major pollinator of this trunk 2.2 litters, averaging five to seven (up died -- but others flourished where flowering species is the blossom bat. to 14) piglets in each. Rabbits produce waters became more shallow. During Honeyeaters, long-tailed pygmy 11-25 young annually and foxes four the last glaciation, about 20 000 years possums, moths, flies and or more. A female toad can lay almost ago, the area which is the Great cockroaches also helped. 100 000 eggs a year. One in 200 Barrier Reef lagoon today was survive to maturity -- and then live up probably a grassy plain where Mass flowering after a long non- to 16 years. Aborigines hunted. The reef itself flowering period is another common would have been on the edge of the Feral pigs from Cape Tribulation strategy of rainforest species. All the National Park show similarities with continental shelf. bumpy satinashes in a region may pigs of Melanesian origin rather then suddenly flower profusely after domestic breeds. They also carry a When conditions warmed sea levels several years without flowers. It has Melanesian tick. They may have rose again. Some reefs were drowned been suggested that this type of originated as the result of trade but others kept pace with the gradual mass flowering is a protection against between Aborigines and people from rise so that the growing coral stayed animals which destroy flowers and New Guinea or Melanesia or may have just below the surface in clear fruits by eating rather than accompanied Kanaka workers from sunlight. Coastlines changed pollinating or dispersing them. Melanesia brought to work on the enormously with these fluctuations sugar cane. Some spotted pigs on Botanists suggest that the sheer Cape York are thought to have been in sea levels, the ocean sometimes abundance of food produced by introduced by Chinese miners. The reaching 250km or more inland from mass flowering and fruiting swamps earliest record of feral pigs in the area the present coastline. is from 1896. Pigs need a diet containing 14% protein before they can breed. In the rainforest earthworms and insects provide this in the wet season, but since these burrow deeply in the dry season it may be one reason for the apparent migration of pigs to the coast at this time. Tourist talk Acclimatization Societies, formed in the 1860s, devoted themselves to introducing exotic creatures to ENGLISH GERMAN JAPANESE Australia. "The objects of the Society shall be the introduction, gai chu pest Plage acclimatization and domestication of yasei no feral verwildert all innoxious animals, birds, fishes, kaihou suru release freilassen insects and vegetables whether useful or ornamental..." Among their most nobuta pig Schwein stunning follies was the introduction neko cat Katze of the Australian possum to New kitsune fox Fuchs Zealand where it is now a major pest. usagi rabbit Kaninchen Happily, they failed to introduce " monkeys to Australia. gamagaeru toad Krote wana trap Falle shuriyou niku game meat Wildbret 6 Exotic fish -- keep them in the tank The Lake Eacham rainbowfish could causing the deaths of aquatic animals. no longer be found in its only known habitat within ten years of having There are heavy fines for releasing been discovered -- because of the exotic fish into natural waters. The arrival of species such as archerfish, contents of aquariums should never mouth-almighty, sooty and banded be tipped into reservoirs, farm dams, grunter and bony bream. These were drains or other waterways -- or introduced to the lake illegally flushed down the toilet. Unwanted fish sometime after 1982 and presumably can be taken to your local aquarium ate the rainbowfish and their eggs, dealer or the local office of the fouled the water and perhaps passed Department of Primary Industries on diseases. It is just one instance of (Fisheries). how vulnerable fish can be. Another source of exotic fish (and Some fish are introduced into our plants) is escapees from overflowing waterways to provide sport and food. garden ponds. Beware the wet season! Others are simply pets which the owners have disposed of Certain fish and plant species are thoughtlessly, thinking that they can considered noxious -- officially fend for themselves in the wild. All too harmful -- and should not be kept. often it is the natives which then have Check with the Department of Primary to do the fending. Industries if in doubt. Exotic fish may eat the locals, or simply outbreed and outcompete them for food and places to live. They may change the habitat, making life difficult for native aquatic life -- for example, European carp destabilise bank vegetation and muddy streams. Exotic fish may also spread diseases and parasites to native fish and other aquatic animals. Pondweeds dumped with the fish can cause enormous problems, choking waterways and Illustrations courtesy ACT Parks and Conservation Service Illegal immigrants in the ballast At least 15 varieties of fish, worms, molluscs, seaweed and toxic algae have arrived in Australian waters in the ballast water of cargo ships. This water is taken on in overseas ports to balance large ships sailing to Australia without cargo. On arrival, this water is discharged into Australian ports and the cargo loaded. If conditions are right, whatever is alive in that imported water can grow, breed and spread. Already predatory fish which may threaten native ones have been found in several harbours, exotic mussels have blocked water pipes, seaweed is outcompeting native species and seastars which feed on shellfish (and breed rapidly) are threatening shellfish fisheries in Tasmania. The Tasmanian shellfish industry has also suffered from a toxic alga which, when eaten by shellfish and fish, causes paralytic poisoning in people who consume them. With about 66 million tonnes of ballast water, 58 million tonnes from overseas, being discharged into Australian ports each year the problem needs to be addressed. Guidelines now recommend that ships take on ballast water in deep water because oceanic organisms are less likely to survive in ports. Other possibilites are to heat or chemically treat the water or to store it on arrival for treatment. If you find any unusual species which you suspect are foreign, please contact the Australian Quarantine and Inspection Service or the health department of your local council. 7 Bookshelf They All Ran Wild Reports The Deadly Seven The Animals and Plants that Plague Feral Pig Management in the Wet Running Riot over Native Species Australia Tropics Peter Beeth Eric Rolls Jim Mitchell, Department of Lands (1993) Angus and Robertson (1969) Article on foxes, wild pigs, goats, cats, (Annotated version 1984) rabbits, buffaloes and cane toads. Community Based Feral Pig Trapping Program A result of years of intensive Brochures Jim Mitchell, Department of Lands research into the history of Feral Animals in Australia (1994) introduction of exotic animals, Introduced Wild Animals in Australia particularly rabbits. Cats in Australia Investigation of Feral Pig Australian Nature Conservation Populations and Control Measures Pest Animals in Australia Agency (1990/1992/1992) Cape Tribulation Section of the Wet A Survey of Introduced Wild Cats and Wildlife Tropics World Heritage Area Mammals DEH (1994) Pav Ecol/DEH (1992) G. Wilson, N. Dexter, P. O'Brien and M. Bomford Proceedings Bureau of Rural Resources (1992) Feral Pig Management Problems in Cat Management Workshop the Wet Tropics of Queensland Greg Siepen and Cathy Owens (eds) World Heritage Area GEO Vol 14 No 3 Aug-Oct 1992 pp DEH (1993) J.C.McIlroy, CSIRO 48-65 This newsletter was produced by the Queensland Department of Environment and Heritage (now The Environmental Protection Agency) with funding from the Wet Tropics Management Authority. For further information contact... Opinions expressed in Tropical Topics are not necessarily those of Stella Martin Wet Tropics Management Agency the Department of Environment and The Editor (For general infomation on the Wet Heritage (EPA). Tropical Topics Tropics World Heritage Area only.) Environmental Protection Agency PO Box 2050 While all efforts have been made to PO Box 2066 CAIRNS QLD 4870 verify facts, the Department of CAIRNS QLD 4870 Ph: (07) 4052 0555 Environment and Heritage (EPA) Fax: (07) 4031 1364 takes no responsibility for the Ph: (07) 4046 6674 Website: www.wettropics.gov.au accuracy of information supplied in Fax: (07) 4046 6751 Tropical Topics. e-mail: Stella.Martin@epa.qld.gov.au