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There is a widely-reported estimate that almost half a billion (480 million) animals have been killed by the bush fires in Australia.

It’s a figure that came from Prof Chris Dickman, an expert on Australian biodiversity at the University of Sydney.

He released a statement explaining how he had reached the figure – a statement which refers to the number of animals affected rather than those necessarily dying as a direct result of the fire (although the title of the release talks about 480 million being killed).

The numbers are based on a report he co-wrote in 2007 for the World Wide Fund for Nature (WWF) on the impact of land-clearing on Australian wildlife in New South Wales.

It estimated that there were an average of 17.5 mammals, 20.7 birds and 129.5 reptiles per hectare (10,000 square…