Researchers in Australia have come out with a new economic impact report that estimates the cost of the top invasive animals in that country. According to this story from the Sydney Morning Herald, the top eleven feral animals, including foxes, cats and rabbits, cost at least $720 million AUS per year ($518 million US). The researchers made some interesting estimates of environmental costs, including losses to the tourist industry caused by a lack of native charismatic megafauna, and increased pesticide use following a drop in insect-eating bird populations (due to feral cat predation). The report, "Counting the Cost: Impact of Invasive Animals in Australia 2004," was produced by the Co-operative Research Centre for Pest Animal Control. Download the full report here.