These little brown critters might look harmless but the World Conservation Union takes them very seriously. They put them in the list of the 100 most invading species in the world and describe them as an extreme threat to Australia. And humans don't get off easily either. Mynahs carry bird mites and have the potential to carry avian-borne diseases that are dangerous to people, not to mention the huge amount of droppings they leave under their communal roosting trees. Often gathering at night in numbers in excess of a thousand, these raucous birds can take over clumps of trees, especially around areas where lots of people go (where they encounter fewer predators) like shopping centres. In a short time their droppings can cover 100% of the ground and public seating under the trees. I speak from personal experience when I say you don't want to park your car underneath them.

What do they look like?
Indian mynahs are easy to recognise. They're about 25 cm tall and mainly chocolate brown, with a black head and neck, and a yellow beak. Some people confuse them with the noisy miner, an indigenous Australian species about the same size. The noisy miner is a honey eater indigenous to Australia, while the Indian mynah is part of the starling family and comes from India. The photos below should help you tell them apart.

Indian mynah
A pest introduced into Australia

How aggressive are they?
I have on some occasions watched Indian mynahs aggressively swooping at other species of birds although most of the time they behave peacefully, hopping about with other species. The noisy miner (an Australian species shown above) is much more likely to be the one seen swooping and charging at other birds, or even at cats, dogs or people! However it seems that the mostly-pleasant nature of Indian mynahs changes when it comes time to move into a nest for breeding. The excellent Birds in Backyards website describes 'violent battles' staged by Indian mynahs evicting the birds that already occupy a nest. This is a common theme in literature about the birds. And in Tim Low's fascinating book the new nature, the author mentions Indian mynahs piling straw right over the top of baby parrots.

So then, what about nesting boxes?
Again refering to the new nature, author Tim Low described a study in Canberra's bushland parks to see which species were using the nesting boxes that had been put up. It turned out that Indian mynahs had taken over thirty five, starlings five, feral honeybees in seven and native rosellas just seventeen. So the way I see it, it seems that putting in nesting boxes just lets the Indian mynahs breed even faster until once again, there aren't enough nesting spots to go around. Apparently, if you want to put in a nesting box then you have to be extremely vigilant to keep the mynahs out.

The sugar industry went ahead and released cane toads into Queensland. Did the cane toads stop the cane beetle? No way. The problem was that the cane toads couldn't jump even remotely high enough to reach where the beetles sat at the top of the cane plants. Instead they walked off and began spreading and spreading and spreading through Northern Australia eating pretty much everything (except cane beetles). So getting back to Indian mynahs, after the dismal failure with the cane toad, Indian mynahs were let loose there too, bringing forward the mynah problems in that state.

Biological control - better left to the experts
In 1925 Australia was in the middle of a crisis with the prickly pear - yet another invasive imported species. The plant had infested more than 25 million hectares and was spreading at a rate of half a million hectares per year. Pesticides and mechanical clearing were shown to be ineffective, so scientists started doing tests with a little caterpillar called cactoblastis. They knew it ate prickly pear, but wanted to make sure it wasn't going to eat everything else.

After lots of testing the little cactoblastis caterpillar was considered safe enough to let loose onto the Australian environment. So they released lots of them on a bunch of prickly pear infestations. The cactoblastis spread through the bush, munching their way through prickly pear at an amazing rate. They didn't wipe out every last bit of prickly pear, but they did weaken it to the point where it no longer threatened to take over.

The cactoblastis campaign against prickly pear is now considered one of the most successful biological control campaigns in the world. The trouble is, in one way it was perhaps a little too successful. Because it received so much publicity for its great work, everyone heard about it and assumed that all you had to do to control a pest was just release another species to eat it. People didn't understand how much work had been done by the scientists to check that cactoblastis wasn't going to cause more damage than good.