Badgers dig up our lawn for earthworms and the nests of ants and mason bees-
a major excavation can be a territorial marking thing as well as a search
for food. They leave conical holes about 60cms and 150cms deep along with
general scratchings.
Most animals dig for a purpose-what is your fox looking for? Our local foxes
leave the occasional fox smell and take chickens fron a nearby paddock, but
lawn digging is not one of their activities.