in Oz feral cats are possibly worse even than rabbits for ecological destruction. no-one except a few greenies that cannot read statistics and reports bats an eyelid if you kill them. i killed at least 80 in 20 yrs, probably 100. they reckon 7 small animals a day to a feral cat so i saved nearly a quarter of a million native lives plus the ones their progeny would have killed. i cant do the maths for cat reproduction but that would be a fair few more. and some feral dogs too. i kept dogs and a cat but breeding was controlled as was activity outside.
fewer feral cats in uk but they all kill birds at any opportunity. i watch them hunt daily, pampered pets that kill.