This is a very distinct difference in the abilities of the American coyote and the British fox with respect to preying on outside domestic cats. In Britain there’s a bit of a myth that foxes ‘murder’ cats. The truth of the matter is that foxes are quite small, weighing less than the average pet cat according to Adele Brand who is a professional ecologist and who loves foxes. And they don’t have terribly effective teeth and jaws, also according to Brand in her book, The Hidden World of the Fox.
The average weight of an adult male fox in Britain is around 6.5 kg or 14 pounds. The weight range is typically between 4 kg to 8 kg or 9 to 17.6 pounds. Domestic cats in Britain weigh on average around 10 pounds (the average appears to be higher in the US). Let’s just say that foxes are not much bigger than domestic cats on average and they recognise the fact that it would be a bad idea to take on an adult domestic cat in a fight because the outcome for the fox would be uncertain. Injuries to predators can lead to death by starvation.
Not long ago there was a lot of discussion about numerous domestic cats (up to 250 I recall) being killed by a mythical human cat killer described as the Croydon Cat Killer. I say “mythical” because the police, wrongly or rightly, decided that this high number of domestic cats were killed by foxes despite the mutilations looking as if they were caused by a man with a knife.
The point that was perhaps missed by a lot of people who could not believe that foxes had killed the cats is that they didn’t kill cats. The cats were probably killed by traffic in car accidents and were then mutilated and partly eaten by foxes scavenging. This is far more likely and it puts the record straight that foxes very rarely attack adult domestic cats.
Coyotes are a completely different kettle of fish. The American coyote is much larger weighing between 20 to 50 pounds, as a starting point. Like foxes they are savvy and clever but their sheer size together with their hunting ability either alone or in packs makes it a much more formidable predator. They sometimes kill lambs, calves and even deer. The adult domestic cat is unlikely to escape a determined attack by a coyote as I understand it.
There have been many reports in online news media about coyotes attacking domestic, stray and feral cats. Coyotes have adapted to the urban environment. I would argue that an important reason why American cat guardians keep the cats inside all time is because of the possibility of a coyote attacking their cat outside. There are other threats but this well-known American predator is a serious one.
The difference between coyotes and foxes in terms of predation on domestic and feral cats is perhaps an underlying and main reason why 95% or more of the British let their cats go outside without supervision while in America there is a much more cautious approach to allowing their cat these freedoms.