Ipswich City CouncilWildlifeFlying FoxesAustralia is home to four species of flying-fox (Pteropodidae) which rely on certain forest types for their survival. Forest Habitats of Australian Flying-foxesThe species and their habitats include - Black flying-fox (Pteropus alecto)The Black flying fox mainly roosts in wet and dry eucalypt forests, mangroves, melaleuca swamps and casuarinas. Black flying-foxes form permanent camps, often with Grey-headed flying-foxes, and feed on nectar, flowers and fruits of native trees and on cultivated fruit (bananas, paw paws, mangoes, lychees) when native food is sparse. Grey-headed flying-fox (P. poliocephalus)The grey-headed flying fox occupies similar habitat to Black flying-foxes (see above) but over a smaller range that extends south into Victoria. Populations that once extended north to Rockhampton are now contracting southward of Maryborough in response to diminishing forest resources. The species was listed as nationally ‘vulnerable to extinction' under the Environmental Protection and Biodiversity Conservation Act 1999 in December 2001. Little Red flying-fox (P. scapulatus)The Little Red is a nomadic species feeding preferentially on nectar, Little Red flying-foxes move seasonally in response to the patterns of flowering eucalypts and paperbarks and form only temporary camps. While they share the camps of Black and Grey-headed flying-foxes during their breeding season, Little Reds breed six months out of cycle with the other three species and the locations of their breeding camps are unknown. Spectacled flying-fox (P. conspicillatus)This species is restricted to coastal Far North Queensland, Spectacled flying-foxes are predominantly rainforest dwellers which can also be found in melaleuca and mangrove swamps. Spectacled flying-foxes depend on the health of tropical rainforests for their continued survival and their numbers have decreased dramatically in recent years as a result of culling at orchards. Seed dispersal and PollinationFlying-foxes have a vital role in the regeneration of native forests. Due to their nocturnal feeding habits and extensive feeding ranges, flying-foxes are able to pollinate tree species which produce most of their nectar at night and are thus less easily serviced by day-feeding birds and bees. The dispersal of seeds by flying-foxes may happen in one of three ways:
Pollen is collected on the fur of flying-foxes while feeding on the nectar of flowers. It attaches mainly to the head and neck region and is thus distributed between different feeding sites. This may lead to cross-pollination between flowers of the same tree or between flowers of different trees of the same species in separate forest patches. Native eucalypts depend on cross-pollination for maximum fruit-set and seed viability. Living with Flying-foxesFlying-foxesIn Queensland, all four species are protected by the Nature Conservation Act 1992, and the Grey-headed flying fox is considered nationally vulnerable to extinction and has been listed under the Environmental Protection and Biodiversity Conservation Act 1999. With well developed sensory systems, flying-foxes rely on eyesight, sound and smell to interact with their environment. Unlike their smaller, insectivorous bat cousins, they do not echolocate or use ultrasound. Flying-foxes weigh between 300-1000gm and have a wing-span of up to one meter. The wings of flying foxes have the same structure as human hands with bones elongated to accommodate the wing-membrane and support the body in flight. LifestyleFlying-foxes are social mammals which spend the day hanging in the canopy of trees at their camp. They fly out at dusk to feed and can travel up to 50 kilometres from their camp-site in search of nectar, blossom and fruit. There are twelve known permanent camps of flying-foxes in the greater Brisbane area, including Indooroopilly, Woodend and Logan. These camps swell in number during the berthing/mating season between November and March. Woodend is home to between 50 000 and 200 000 bats at various times of the year, although larger numbers may aggregate in response to seasonal food shortages in the wild. Female flying-foxes become sexually mature at 2-3 years and give birth to one young per year. Young are cared for during a period of three to four months after which they become independent. In urban environments, flying-fox hazards include goannas, snakes, powerful owls and eagles, and introduced ones such as foxes, dogs, cats, humans, powerlines and barbed-wire fences. Provided these can be avoided successfully, a flying-fox may reach 8-10 years of age. NoiseFlying-foxes use sound as a means of communication. Their hearing is similar to humans, making their calls clearly audible to our ears. Vocalisations between individuals are necessary for social communication, eg: during the defence of territories. Periods of noise occur mainly at dawn and dusk when the bats arrive at or prepare to leave the camp. Calls during the day occur mainly during the mating season in March/April or as a response to disturbances. These may include roaming dogs, birds of prey, planes, machinery noise (chain-saws, lawn-mowers, loud bangs) in or near the camp or people walking among the roosting bats. Flying-fox noise can be minimised by preventing disturbances at the camp sites. Away from camps, flying-foxes can sometimes be heard feeding in trees at night. Flying foxes are loyal to feeding sites; noise indicates the defence of feeding territory and will cease as soon as the trees in which they are feeding finish flowering or fruiting. OdourAmongst flying-foxes, odours are used for identification and as attractants during the mating season. The scent is stronger in males, who secrete it from scapular glands and use it to mark their territory and to attract females during the mating season. Scents emitted by young which are left behind in camps at night allow mothers to locate their infants in the colony. Flying-foxes defecate primarily at their feed-sites, not at their camps. Smell is therefore not generally caused by a build-up of faeces underneath the colony, but by the bats themselves. As in other mammals, this may be intensified by very hot or humid weather when bats sweat and fan themselves to keep cool. Droppings/GuanoFlying-foxes can defecate in flight, splattering objects beneath their flight path with excrement or guano. Guano is easily removed with water and does not pose a serious health hazard. In swimming pools it is neutralised by normal chlorination. To avoid damage to lacquered surfaces, cars parked in the street can be covered with a tarpaulin. To avoid the contamination of rainwater tanks with guano from bats, birds and other animals, keep tanks covered, chlorinate regularly and drain and clean the tank and area used for water collection on a regular basis. The spillage mechanism of the first flush following rain is the best way of keeping your tank clean. Flying-foxes in Fruit TreesAlthough flying-foxes prefer the fruit and nectar of native plants such as eucalypts, paperbarks and figs, they will also feed on cultivated fruit, especially when there is a shortage of native food. Fruit that has been partly eaten by flying-foxes should not be consumed by people. Fruit covered in guano should be washed thoroughly and peeled prior to consumption. Non-peelable, contaminated fruit such as mulberries should be avoided as a matter of good hygiene practice. Encounters with Injured BatsOccasionally, juvenile or injured bats may be found on the ground or caught in barbed-wire fencing. Do not handle these animals, but immediately contact the Queensland Parks and Wildlife Service on (07) 3202 0200 and your call will be directed to a qualified wildlife carer. In case of a bite or scratch injury, wash injury site thoroughly with soap and water and contact your local GP. Management of Flying-foxesBackgroundIn recent decades, the increasing modification of our natural environment has had a detrimental impact on most species of flora and fauna, including flying-foxes. Extensive clearing of native forests for agriculture and urbanisation has diminished the habitat of much of our native wildlife to small, isolated patches. The loss of this forest resource and its function as food-provider and roosting habitat has led to an increased confrontation between flying-foxes and people. Small forest remnants in urban areas are often over-crowded with bats, and seasons of poor fruiting and flowering in nature force hungry flying-foxes to turn to cultivated fruit as an alternative. In an effort to reduce mutually disturbing confrontations between bats and humans, a number of different management strategies have been employed with varying degrees of success. Culling/PoisoningThe reduction of local flying-fox numbers by means of shooting or poisoning (illegal) is a long-standing, ineffective tradition in Australia. Orchards are most affected by bats when native food-resources are extremely scarce and cultivated fruit provides the only alternative to starvation. While a small number of bats can be removed by shooting, this does not deter bats from returning later. Shooting creates a ‘sink-effect', whereby new bats take the positions vacated by the dead bats in the food trees. Apart from briefly, and often illegally, venting the frustration of fruit-growers, culling does not protect orchards. In Queensland, all flying-foxes are protected by the Nature Conservation Act 1992. The Grey-headed flying fox is also protected nationally under the Environmental Protection and Biodiversity Conservation Act 1999. Culling can only be undertaken via a permit from the Queensland Parks and Wildlife Service (ph: 07 3202 0200) where significant economic loss is proven and other methods have failed. NoiseThe installation of high-frequency emitting bat-repellents has repeatedly been trialed with high hopes of success. Contrary to popular belief, flying-foxes do not use echolocation or ultrasound as a means of negotiating their environment. Their hearing range is similar to that of humans, making high-frequency sound inaudible to them. Sounds that can potentially detract flying-foxes have an equally offensive effect on humans and meet with very limited popularity in the neighbourhood. The banging of metal drums was employed by Sydney City Council to disperse flying-foxes from the Botanic Gardens and this strategy was abandoned due to lack of success in 1998. Bright or Flashing LightsStrobe lights and other bright or flashing light sources installed in trees have been similarly unsuccessful as bat deterrents. While flying-foxes may be disturbed initially, hunger and desensitisation to the light causes the effect to be short lived and may eventually serve to attract the bats. Driven by desperation, flying-foxes will become accustomed to most novel stimuli in a matter of days or weeks. Pungent OdoursDue to the bats' highly developed sense of smell, strong and unpleasant odours would seem the most likely detractor of flying-foxes. Pungent kerosene, creosote, and more recently fish paste and snake faeces, have been placed in fruit trees with limited success. While odour detraction may warrant further investigation, hungry bats are likely to habituate to it if no food alternatives exist. Protecting Your TreesBackyard Fruit Trees: Small individual fruit trees can be protected from flying foxes using netting stretched over a home-made frame, for example, by inserting lengths of poly-pipe over metal star pickets driven into the ground. Space bars of pipe or wood stabilise the frame at the top. Knitted nylon 40mm mesh or netting is stretched taut over this frame and securely pegged to the ground. Warning - fine nylon netting loosely hung over fruit trees entangles wildlife often causing fatal injuries. Bagging individual clumps of fruit with brown paper bags or old fertiliser bags has also proved successful. Orchards: The exclusion of flying-foxes from fruit trees via a cover of specially designed netting is currently the most effective protection available. Although netting involves an initial financial outlay by fruit-growers and not all orchards may be suitable, the benefits of installing this type of cover where possible are considerable. In addition to excluding flying-foxes, netting also excludes equally invasive birds and may improve the setting of fruit by limiting bees and other insect pollinators to an enclosed environment. While the number of effective management strategies at this stage is clearly limited, research into improving flying-fox management continues. Several options already exist which will help to minimise the negative effects of flying-foxes and humans on each other. The most urgent of these is the planting of native food sources to lessen the impact on cultivated fruit. Maintaining and improving native forest resources is the only management strategy which will be effective in the long term. Flying-foxes and public healthSummarySeveral apparently new viruses capable of causing diseases in animals and humans have been linked to bats in recent years. Of these, Hendra virus (equine Morbillivirus) and Australian bat Lyssavirus are the most notable. Research by the Queensland Department of Primary Industries (DPI) and others has shown that some species of bats act as a natural reservoir of infection for these viruses, and so members of the public are strongly advised against handling any bat. Only those few trained individuals who are protected by vaccination and suitable equipment should care for bats. Australian Bat Lyssavirus (ABL)A newly identified virus capable of causing a rabies-like disease in bats and humans was first identified in a Black Flying-fox in northern New South Wales in 1996. Research to date has shown the virus to be present in four species of flying-fox in Australia, and in two species of insectivorous bat. Given the invariably fatal consequences of human infection with Lyssaviruses, we need to assume that any and all Australian bats have the potential to carry Australian Bat Lyssavirus. ABL infection in humans is extremely rare; only two human cases have ever been documented in Australia. Infection is thought to occur by a penetrating scratch or bite, whereby virus in an affected bat's saliva comes into direct contact with exposed tissue. There is no evidence to suggest that contact with bat urine or faeces poses a risk of infection, nor that bats flying overhead or feeding or roosting in trees pose any risk to humans. Infection with ABL has not been reported in any other species than bats and humans. Bats are regarded as the natural reservoir of ABL, and research findings to date suggest that while infection in bats is uncommon (perhaps less than 1% are infected at any time), it has been found in bats across much of Australia. It is probable that the virus has been present in Australian bat populations in Australia for a very long time. Further research is being conducted into the distribution and transmissibility of the virus. ABL is not known to be spread by ingestion, however, as a general hygiene measure, fruit that has been damaged by any animal should not be eaten, and fruit which has been soiled should be washed and peeled before being eaten. Minimising the risk of exposure:The known risk of Lyssavrius infection relates to being bitten or scratched by an infected bat. The best approach is to leave bats alone. If you find a sick or injured bat or encounter a bat caught on a barbed-wire fence, do not touch the bat but call your local Queensland Parks and Wildlife Service office on 07 3202 0200. If you are bitten or scratched:If you are bitten or scratched, wash the wound carefully with soap and water for at least five minutes. Do not scrub the wound, but do wash it thoroughly. Proper cleansing of the wound is the single most effective measure for reducing transmission of Lyssavirus. Contact your doctor (even if you are already vaccinated) who will contact the local Queensland Health Public Health Unit to arrange appropriate treatment that may include vaccination or booster vaccination. If you get bat blood or saliva in your eyes, nose or mouth, you should flush the area thoroughly with water and seek immediate medical advice. In addition, as with any animal bite or cut, you should check your tetanus vaccination status to see if you need a booster. If possible, the bat should also be collected for tests but do not handle it yourself. Contact the Queensland Parks and Wildlife Service as soon as possible to arrange collection. Hendra Virus (equine Morbillivirus)Hendra virus was first identified in 1994 when it caused the death of 13 of 20 infected horses in Brisbane. Subsequent research has shown that a virus isolated from flying-foxes is indistinguishable from the virus found in the affected horses, and it is now widely believed that flying-foxes (fruit bats) are a natural host of this virus. There have been three known human cases of Hendra virus disease in humans, two of which were fatal. On each occasion, sick horses appear to have been the source of infection to humans. There is no evidence that Hendra virus can spread directly from bats to humans. Antibodies to Hendra virus are widespread in Australian flying-fox populations, and it is probable that the virus has existed in Australia for a very long time. Spillover infection to horses is a very rare event. Bat DroppingsSome types of bacteria (such as Salmonella) which can impact human health are found in bat faeces from time to time, and members of the public occasionally express concern about potential contamination of swimming pools or rainwater tanks. Rainwater tanks:If the droppings of any animals collect on your roof, and you collect that rainwater for drinking purposes, contaminants could wash into your rainwater tank. In these instances, it is advisable to have a device that allows the first flush of rainwater to be diverted from your tank. It always good hygiene practice to keep your rainwater tank covered, and at regular intervals chlorinate the tank and drain and clean both the tank and the roof area used for rainwater collection. Swimming pools:Normal pool maintenance practices (cleaning, filtration and chlorination) should remove any contamination associated with flying-fox droppings. The above onformation was prepared with the assistance of the Queensland Dept. of Primary Industries (Animal Research Institute) for the Woodend Nature Centre Advisory Committee, in collaboration with Queensland Health (Central Public Health Unit),and the University of Queensland. Further Information
Last Updated 16 Oct 2007 |
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