One issue that seems not to have been considered is whether the bird repellent devices are likely to be successful. I have worked in the area of bird deterrence on airfields for nearly 15 years, mainly at Chek Lap Kok airport. In the literature I am familiar with, there is little evidence that static or automatic bird scaring devices are successful in the long term. They may have a short-term impact, but after a short while habituation occurs. In other words, birds become accustomed to the noise or visual disturbance, realise it is not a threat to their well-being and, after a while, simply ignore it. It reminds me of an observation made by David Melville at Kai Tak airport, where gas cannons were deployed to scare birds. David saw Black Kites perching on the cannons; every so often, when the birds felt the firing mechanism commence, they would lift off a short way while the cannon fired, and then simply drop down again to resume their rest.
Ultrasonic devices have only been proven to work with two types of birds: owls and, perhaps rather surprisingly, Barn Swallows. There is absolutely no evidence that other species even hear ultrasound! While CDs and coloured ribbons, as well as effigies and other items, are deployed in many parts of the world, there is no evidence that these work for anything other than a short period of time. It is thus likely that, in the case of LV rice, the effect would simply be to extend the time the munias require to strip the fields of rice by a few days. Static devices are also subject to the same habituation effect.
It is only when these acoustic and visual devices are used by humans in a highly visible way that there can be said to be long term impact. That, however, requires substantial investment of time and effort.
The accepted view is that, if you want to deter birds from an area, then you make sure the habitat that attracts them is not present (the South Korean government is well aware of this!). Obviously, this is not an option in this case, and it seems to me that if it is desired to exclude birds from a particular area of rice paddy, then probably the only effective way is to enclose it with netting through which birds cannot pass.
I must confess to being slightly unclear as to what is happening in the LV case. Is the rice is being sold as income for the project? If so, is the rice not harvested before it becomes highly attractive munia food? Like MikeT, I'm slight puzzled as to why ECF thinks that income, public involvement and publicity are so important. But perhaps that's simply due to our ignorance of the aims of the ECF and this project? And if these things are so important, then whether we support 7 or 10 or 15 Yellow-breasted Buntings may not be very important. It's still a very small proportion of the population, and there are probably ample food supplies elsewhere in northwest NT. I realise, of course, that these buntings are part of the educational resource, but so are thousands of munias and the other common species.
My feeling is that if it is required to save a portion of the rice for some purpose, then do so with an effective measure, and not techniques that are not proven as successful. As for the rest, simply let nature take its course, and exploit it for educational purposes in any manner it allows.
GeoffC
