Yahoo! News has a story about the impact of European red fox (Vulpes vulpes) control programs in Western Australia. The government, concerned that the removal of foxes from the ecosystem may have led to an increase in the number of feral cats, have now announced a $16 million AUS program to control the cats, which are apparently a bit smarter than foxes when it comes to taking the poison bait. As state environment minister Mark McGowan notes, "There is a strong suspicion that this is due to an increase in cat numbers, as a direct consequence of the decrease in fox numbers."
Suspicion eh? The fox control program has been in place for several years (see this older ISW post). A quick Googling brought up this press release from CSIRO, where a researcher brings up the possible positive effects on feral cat populations if foxes are removed from the ecosystem. There is also this report from the Australian Department of the Environment and Heritage that provides more information, including several examples of expanding feral cat pops. Both refer to work done back in the late 1990s!. Hmm...does Dr. Molsher get to say "I told you so!" now?
Update: As commenter Roadkill Goanna points out, Tasmania can no longer claim to be fox-free. This article from The Australian notes that foxes have been in the country since at least 1998. Thanks Roadkill! (never thought I would type that phrase :-) )