Other than natural predation, weather and food shortages, the most common man-made hazards that affect Flying-foxes in S.E. Queensland include:
Entanglement in fruit tree netting
Fruit tree netting thrown loosely over a fruiting tree is a dangerous trap for all nocturnal wildlife, especially bats as they get tangled very quickly. Once caught, they can suffer cruel and extensive injuries, even death, depending on how long and how badly the bat has been entangled. Inappropriate netting is readily available via suburban hardware stores to backyard growers and the danger to hungry wildlife is becoming a major threat to their survival if people do not check their nets daily or erect them properly. There are alternatives to using netting to protect fruit trees. Guidelines for fruit netting
Entanglement in barbed wire
There are kilometers of barbed wire across Australia and it not only affects Flying-foxes but many other animals. It is largely the nocturnal wildlife that is at most risk, and many rescues from barbed wire occur where there is a nearby fruiting or flowering tree and they have been caught on approach or departure from this food source.
Flying-foxes simply cannot see the wire strands at night but some success has been reported from tying tape, old CD's or other visible markers on the top strand.
This is an uncommon occurrence in SE Queensland, however in some parts of FNQ it is a serious problem. The impact of severe tick infestation on Spectacled Flying-Foxes during the 2004-05 bat season was immense. The popular theory is that they are obtaining the ticks from tobacco plants which are low to the ground. Bat Rescue Inc. was directly involved in the rescue effort of Spectacled Flying-fox babies orphaned as a result of ticks in 2004-2005 (see the report under Special Projects for further information).
With increasing habitat destruction and urban sprawl, wildlife are forced to live in closer proximity to humans than ever before. Flying-foxes have also adapted to take advantage of the backyard fruiting and flowering plants and are becoming increasingly urbanised. Large gatherings of the animals as they follow seasonal flowering can also result in local residents becoming annoyed by noise and smell issues and calling for the colonies to be relocated. There are strict guidelines regarding deliberate colony disturbances and relocation attempts, and these can result in poor outcomes for the Flying-foxes depending on the methods and time of year it is conducted.
Electrocutions/electroshock on powerlines
Flying-foxes can come into contact with powerlines when fruiting or flowering trees are growing amongst or near the wires, but this is not always the case as the photo indicates. There were four bats electrocuted on this particular occasion in a once notorious stretch, but Energex have bundled the cables to prevent any more deaths.
Injuries most often occur when resting on the lines and when two lines are touched simultaneously by their wings. Unfortunately the outcomes are usually fatal. Those that are not electrocuted outright but receive an electroshock usually have to be euthanased due to their injuries.
A dependent flying-fox baby being carried by its mother (during the months of October-December) often survives and can remain hidden in the folds of its dead mother's wings for days before eventually dying of starvation and fly-strike, unless it is rescued. Report all bodies on powerlines (make a note of the pole numbers) to your local wildlife group or electricity company. Helping to identify stretches of powerline that are regular deathtraps to bats and other wildlife supports the need for rectification by the local electricity company or pruning of nearby food trees. Inconvenience to the local residents through power disruptions can also be avoided.
Entanglement in fishing line
Flying-foxes like to feed on the flowering mangroves that line river banks. Unfortunately, careless fishermen leave tackle. Discarded line can be snagged or washed into the trees during high tide. This is a problem in heavily used waterways such as the Noosa River, Moreton Bay and the canal estates and waterways on the Gold Coast
Orchard protection methods
There are legal and illegal methods in use today, however the culling of any wildlife is illegal unless a damage mitigation permit has first been obtained from the Queensland Parks and Wildlife Service. It is believed that culling for the protection of crops has played a significant part in the rapid decline of Flying-fox populations in recent years. Several court cases prosecuting growers for illegal practices have shown some of their methods have severely impacted local populations with the deaths of hundreds if not thousands of animals over a short period of time when fruit crops are ripening.
Cocos Palm - Syagrus romanzoffiana
This South American palm has been a popular garden and street tree for its fast growth and tropical look. It is now regarded as an undesirable plant due to its rapid spread into bushland and its harmful effect on many species of wildlife. Tree lopping companies say it is keeping them in work as it becomes increasingly unpopular with gardeners and councils due to its high maintenance costs.
Above: Grey-Headed Flying-fox entangled in shredded cocos palm fronds
Cocos palms can affect Flying-foxes in the following ways:
- Poisoning when seeds are eaten green in times of hunger (September to January)
- Sticky fruits can cause severe constipation causing dehydration and death in young animals
- Toes caught in flower sheath causing self mutilation and death
- Whole body or body parts caught in leaves that are easily shredded by claws creating a 'cocoon' effect around the animal causing stress and death if not physically removed. See photos above of entanglement
- Juvenile animals can get seeds caught at the back of their 'dog like' incisor teeth causing a slow death from starvation
- Premature wearing of teeth due to the hard seed. Flying-Foxes have been known to live for 30 yrs in captivity but wild animals who appear young are now presenting with worn, missing or even no teeth.