Foxes take cats frequently here in Norway. They don't always succeed.    Our mean old farmyard tabby came home several times with fox fur in its claws (maybe HE was hunting THEM!?). Finally, he didn't come home. I've seen a fox walking down an early morning street with a dead cat dangling from its mouth in the town where I live in Norway. On the whole I would assume they mostly get old, sick and young cats, but the common assumption when ANY cat goes missing in the country is that "Mikkel" (fox's nickname) got him/her.
I once watched a fox work its way down a cliff to the spot where sea gulls were nesting, with a veritable cloud of angry gulls above it: swarming, diving, pecking,shitting, spewing gall and just generally raising holy hell in that skull splitting way of theirs. The fox finally reached a nest, grabbed one egg in its mouth and made his way up the cliff again, gulls following. Maybe foxes here just like challenging meals?

Bassen