THE number of collisions between Australian passenger planes and birds and bats has more than doubled in the past decade, despite airports using extreme tactics to scare them off, including gas cannons, blow-up figures, fireworks and imitation-hawk kites.
Such collisions, known as bird or bat strikes, are a significant safety threat and have caused serious accidents around the world, including the engine failure that forced US Airways flight 1549 to land in New York's Hudson River in 2009. A pair of Canada geese were ingested by two of the aircraft's engines just minutes after takeoff.
A report by the Australian Transport Safety Bureau found the number of strikes increased from 400 to 980 in large passenger aircraft between 2002 and 2011. This year, 1450 animal collisions with Australian aircraft have been reported.
Melbourne Airport recorded 58 bird strikes last year, Avalon 14, Essendon five and Moorabbin eight.
Bureau spokesman Stuart Godley said bird and bat strikes were one of the most common safety hazards.
''While it is uncommon for bird strike to cause any harm to crew or passengers, some do result in damage [to aircraft] and some have had serious consequences such as forced landings and broken windscreens,'' said Mr Godley, the ATSB's research investigation and data analysis manager.
Strike damage costs airlines millions of dollars each year.
The head of the Australian Centre for Wildlife Genomics, Rebecca Johnson, whose team uses DNA analysis to identify animals struck by planes, said the impact these flying animals could have on aeroplanes was extraordinary. ''The fan blades in [some] engines are the highest quality alloy and something like an ibis can tear those,'' said Dr Johnson, whose laboratory at the Australian Museum in Sydney receives about five tissue samples - blood or feathers - a week.
''When you have two things travelling in opposite directions towards each other, the speed and the concentration of mass colliding in one small area explains why they can do so much damage.''
Bird strike consultant Phil Shaw said while the total number of strikes had increased alongside a rise in flights in the past decade, the strike rate - the number of collisions per aircraft movement - had also grown.
He said the rise was due to many factors, including the growth of regional airports that did not have the resources to effectively manage wildlife, as well as bigger and quieter aircraft.
''They're able to sneak up on birds,'' he said.
Airports, with their ponds, creeks and grassy vegetation, had also become little oases for birds in urban environments.
The loss of flying fox habitat, which forced the mammals closer to cities, was behind the dramatic rise in bat strikes, Mr Shaw said.
Airlines must report all strikes and near misses, but it is the airports that are mainly responsible for reducing animal hazards.
Mr Godley said it was hard to tell whether bird strikes were increasing or pilots were reporting minor incidents more frequently. Most accidents had been low-risk strikes with small birds causing no damage, he said.
Dr Johnson said collisions were most likely to occur during landing and takeoff. ''That's the altitude most species fly,'' she said.
The Australian Museum's DNA facilities to identify which species were most commonly involved in plane collisions helped airports implement species-specific management programs, she said.
''[Animal strike] is not something that can be eliminated, but it is something airports dedicate effort to mitigating.''
Many metropolitan airports relocate bird nests and use flashing lights, sirens and fireworks to scare bird flocks. One of Melbourne Airport's tactics is to use ''Scary Man'', an inflatable figure with an alarm that operates about seven times an hour.