Downside to colonisation

It is a pity that when folk come to start a new colony on the other side of the world, they feel compelled to bring part of their old home with them.
Here in Victoria, in this rather English of Australian States, we have sparrows, starlings, blackbirds, rabbits, domestic (now feral) cats and a predator with no other predator, the Fox.

I was driving down a quiet dirt road outside of Geelong when I spotted 2 collections of fox carcases. What are they doing here? Have they stopped the foxes from entering the field? Have they reduced the population a little?
Who knows?
Interestingly, their tails had been skinned for the fur.