The common Indian myna bird is fast becoming Australia's number one feral enemy! In autumn, mynas start to aggregate in large flocks - providing the perfect opportunity to trial a new trap that could finally provide a way to remove these clever and aggressive pests.
The myna bird has been declared the second greatest threat to native birds after land clearing. It's currently spreading through eastern Australia, yet in some areas its arrival is so recent that unknowing residents welcome it into their backyards and encourage it to feed alongside native birds.
First introduced to Australia to control insect pests, the arrival of the Common Indian Myna (Acridotheres tristis) in a region signals a disastrous change to come in local bird populations. This extremely aggressive bird chases out native birds and small tree dwelling marsupials such as feather-tailed gliders.
It's not just Australia that is suffering from the myna onslaught - in 2000, the International Union for the Conservation of Nature (IUCN) declared the bird among '100 of the World's Most Invasive species', and for good reason. It is now a pest bird in many regions from Singapore to the Seychelles, and has pushed native birds towards extinction in Polynesia, Hawaii, and Mauritius.
Dubbed the 'garbage bird' because of its unseemly habits, myna birds flourish wherever humans live, their populations booming around garbage tips, factories, schools, shopping centres and dumped cars. And their presence may also have health implications for humans.
Calling Australia home
Native to India, the cocky brown-and-black myna with its characteristic yellow eye-patch has become an unwelcome but all too familiar sight in many parts of Australia. Sydney, Melbourne and Canberra in particular have become favourite myna haunts and the myna has been pushing relentlessly north and westwards from its major population base, on a path following the highways and towns where it thrives on the rich bounty of human society.
"The numbers have exploded here in the past 18 months - they've probably increased 10-fold", says Mark Graham, a terrestrial ecologist with Coffs Harbour council and a member of the North Coast Vertebrate Pest Working Group. "They are now up and down the entire coast, except for the highest areas". Graham says the birds have spread beyond the towns out into the surrounding farmland and in particular, areas which border farm and bush.
In south-east Queensland, mynas have only recently arrived, with the locals just beginning to experience what it is like to live with the 'flying cane toad'. In the Queensland city of Caloundra, city councillor Pauline Clayton says the birds arrived about two years ago. The council is urgently preparing a policy to control mynas, which Pauline hopes will be adopted by all councils in the south east Queensland region.
And they are also making their way south - a pair that turned up in Tasmania just before Christmas were quickly despatched, but others not doubt will follow them.
When: Autumn - March, April, May
Where: East coast of Australia - Sydney, Melbourne and Canberra in particular have become favourite myna haunts and the myna has been pushing relentlessly north and westwards.
Other info: In Autumn mynas have finished breeding and have begun to aggregate into large flocks. This is the best time to catch birds in large numbers.
Mynas compete aggressively for nesting hollows, chasing away competitors and even throwing other birds' chicks out of the nest. President of the Queensland Ornithological Society Peter Crowe says he witnessed a group of nesting mynas going to the trouble of filling up nearby vacant nesting hollows with rubbish - the mynas didn't need the extra nests, but they sure as hell won't going to allow any other bird use them!
Closer to home, mynas love nesting in the roofs of houses, and the accumulated droppings and mites are a breeding ground for disease. Inhaled mites can cause asthma and hay fever, and their bites cause itching. Once the baby birds have fledged, the mites get hungry and move down into the house in search of alternative food - the human residents. Peter Blythe of the Central Coast Common Myna Action Group warns that Common Mynas have the potential, as do any birds living close to humans, to spread salmonellosis, Newcastle Disease, Avian influenza and infections leading to pneumonia.
For years, bird lovers watched in despair as Common mynas came to dominate the local avifauna in town after town. But after seeing this feathered tide gradually take over formerly peaceful towns with their raucous calls and bad attitude, community groups and councils from Caloundra in Queensland to Anglesea in Victoria and as far west as Albury on the NSW/Victorian border are marshalling forces. After several years of intense research the fightback has begun, the first serious and widespread attempt ever to stop the myna invasion.
Councils and community groups up and down the coast are setting up hotline numbers to track the spread of the birds, with one council even considering putting a reward on every myna's head. Local residents are being asked for eternal vigilance, with press ads, radio promotions asking for reports of any sightings. Those living away from the towns on rural properties are dusting off their rifles and taking up arms against this new winged enemy.
"We are starting an education and awareness program through the local media," says Ms Clayton. "We're saying: 'here's what they look like, and they are arriving here now. People don't know what they look like - or they think they are native".
One of Peter Blythe's concerns is the widespread planting of palm trees. "Whenever they build a new shopping centre, they put in palm trees, and the mynas just love them," he says. A project manager by profession, Peter Blythe started the Central Coast Indian Myna Action Group to educate the public and local businesses about mynas - and he's thinking really big: "If we could have 200 members trained to operate 20 traps, and each trap catches about 50 birds per week - that's 200,000 birds!"
In Albury Wodonga, the town is still myna-free, but their nearest stronghold is only 70km away at Wangaratta, and getting closer. Local government, council and bird groups including the Albury Wodonga Field Naturalists have joined forces to keep the area free of the bird. A 'wanted' poster has been sent out with a detailed description of the bird, asking for reports of any sightings. The birds rely on leftovers around petrol stations and roadside restaurants to sustain them as they travel from one town to another, so they too are being summoned to help, by keeping rubbish sealed away from marauding birds, and blocking up any nests that appear under eaves.
Outsmarting the bird
While the desire to catch mynas has never been lacking, they have always eluded their captors with their intelligence and complex behaviour. They quickly learn to evade any trap set for them and if caught, warn their comrades to stay away with loud distress calls.
Like the Velociraptor in Jurassic Park, these creatures are clever and seemingly unstoppable. Mynas have an extremely broad diet, ranging from fruit to insects, lizards and even small fish. Any attempt to restrict their food has resulted in mynas merely shifting to another food. Poisoning, a favoured method for controlling pest birds, has also failed to provide a solution: there are too many risks the bait might be picked up by native animals, children or pets.
But mynas do have their weaknesses, and these have been cunningly exploited in a new trap specifically designed to catch the birds. The trap was launched this year and is now undergoing its first broad scale trial. Developed by Dr Chris Tidemann at the Australian National University, the myna trap is relatively low-tech, but relies on a sound understanding of the biology and behaviour of mynas.
Tiddeman has chosen autumn for the trials, because the mynas have finished breeding and have begun to aggregate into large flocks. This is best time to catch birds in large numbers, he says.
"I think you need a bit of understanding of the psychology of the bird," says Tidemann. "They are highly intelligent and learn to avoid traps when they hear the distress calls of their companions. The reason this trap works is because it doesn't alarm them."
After testing four prototypes over the last few years, Chris came up with the current design. The trap is made up of two sections, a base for catching the birds and a top for roosting. Here, under cover, perches, food and water are provided. The birds willingly enter the trap at the bottom to feed on pet food, entering through special valves designed to allow in only mynas and closely related starlings.
What's different about Chris's trap is that it offers a home away from home for the birds, inviting them in and enticing them to stay. Birds are free-fed for several days and once trust is established, they are easily caught. Sometimes a pair of birds are placed in the trap to lure others in. While its dark and the birds are roosting quietly, the top section containing the birds can be removed, and the birds humanely destroyed with carbon dioxide. The trap can then be used again the next day.
"It's been a long haul to get this far," says Tidemann. "I'm pleased it offers a mechanism where communities can do something themselves to help the biodiversity."
In the biggest test yet, Tidemann has place traps throughout Canberra suburbs to see just how many birds can be removed, and how long the area will remain clear. "We hope to catch about 50 birds per trap per week, there are six traps and we'll being doing it for two months, so catching a few thousand is likely," he says. "But this would be an ongoing process - it's not sensible to think 'one whack and they're gone'. It's a bit like weeding."
The trials will tell Tidemann what the cost benefit of the traps are: how many traps, and how much time is needed to catch a certain number of birds. It will also enable researchers to monitor whether or not the birds reinvade a cleared area, and how quickly this happens.
"If technology to reduce their numbers can be made available and enough people use it, people power may indeed be able to beat the myna, at least on a local scale," Tidemann says.
Peter Blyth is also optimistic, but only if enough effort is put in. "How much impact could it make on the population? It all comes down to the will to do it," he says. "You get enough people out there trapping mynas, and you'll make a real dent in the population."
Further info and credits
Special thanks to:
The Central Coast Indian Myna Action Group
Kind permission to reproduce images given by:
Dr Chris Tidemann, The Australian National University
Published 08 April 2004