The hunting behaviour of pet cats has significant wildlife impact, and simple interventions including bell collars reduce predation substantially.
Bell collar effectiveness has been questioned by some cat advocates, but the evidence for significant predation reduction is robust when bells are in good working order and audible. Wildlife welfare and cat welfare are not opposing goals — reducing hunting exposure also reduces injury, disease exposure and the welfare consequences of unsuccessful hunts including wounds from prey animals. Birdsbesafe collar covers, which exploit birds' superior colour vision, appear more effective than bells alone. Keeping cats indoors overnight when predators are most active eliminates nocturnal predation entirely. A combination approach — bells, bright collar covers and curfews — provides the greatest protection.