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Many fruit growers see flying-foxes such as the Grey-headed Flying-fox as a threat to their livelihood. Understandably, when large numbers of the animals suddenly enter orchards and cause significant damage, growers start to talk of “population explosions” of the animals. In this paper we describe the seasonality, longevity and low reproductive potential of flying-foxes, and show that rapid expansion of their populations, at rates comparable to those of small rodents, simply is not possible. Sudden incursions of large numbers of flying-foxes into orchards reflect migration of animals into a food source from elsewhere. The “natural” longevity of flying-foxes and low reproductive rate of only one offspring per female per year reflects the environment in which these bats evolved - one in which they suffered a low annual mortality and could afford a low reproductive rate. We show that the major factor which determines the rate at which flying-fox populations increase or decline is mortality, and that an additional annual mortality of 10%, “imposed” (for example by “culling”) upon the animals' “natural” mortality, could lead the entire Grey-headed Flying-fox population into decline. Because of the animals' mobility, localised culling (as in the Melbourne Botanic Gardens) will not solve problems caused by the bats and, if continued, will act as a pteropucidal black hole, attracting to their deaths a continuing stream of animals from far afield. If the community wishes to protect flying-foxes, then it must recognise the genuine concerns of growers for their livelihoods, subsidise non-lethal modes of protecting crops, and provide support for research into cheaper and more effective means of protection.

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