For several years we had a pet door insert in the slider door for our daughter's little dog to use. Most of the cats used it, too, and periodically they would bring their prey indoors and present it to us, sometimes dead and sometimes alive. Sometimes we didn't know about their gifts until we realized a live mouse was at large in the house. Traps were set and cats were (uselessly) berated. Now the dog is gone, and the pet door is gone, so the mice are no longer brought in. But we are now expected to provide nonstop door service for the one remaining cat, and his needs are great.