A huge amount of the comment here and elsewhere on this research anthropomorphises cats - accusing them of "murder", "torture" &c. &c. All this misses the point entirely. Cats are much more hard-wired than many of us would like to believe. They are to a large extent stimulus-driven automata, pre-programmed to pounce on small animals that move in their field of awareness.
That means it's the responsibility of the "owner" (although nobody really 'owns' a cat - it simply occupies a territory that you may also occupy) to minimise the damage a cat can do - particularly in densely populated urban environments. The simplest fix is a collar with a bell on it, but it has to be a sensible bell, not the tiny token gesture fitted as standard to most commercial cat collars.
A bell does not so much alert the prey as distract the cat by spoiling its stealth as it springs - provided the cat can hear the bell and it is fitted when the cat is young enough. If it works, operant conditioning eventually sets in, reducing the incidence of the predatory behaviour.
Nevertheless, the biggest problem for prey species is not the behaviour of the individual cat but excessive predator density. Where I live, nine or ten cats have "homes" within an area of one acre (18 residences). This is at least 20 times the natural predator density, and is only sustainable for the predators because the cats are artificially fed. It is however, completely unsustainable for many of the prey species.