Sam used to be an outdoor cat, roving the neighborhood and, from time to time, getting into fights with other cats. As he got older, he began coming home with visible injuries, injuries requiring frequent visits to the vet and lots of antibiotics to ward off infections. When we moved to Portland, we decided it was time to stop the forays into the Great Outdoors, partially to end the abcesses and other injuries and partially to stop the hunting/killing of birds.
Our vet in California told us that most outdoor cats became accustomed to staying indoors after a month or so, but she clearly didn't know Sam at all. This morning, after fifteen months of indoor life, Sam escaped through the sliding door that leads to the back deck and yard (which had been left open by a house guest) and disappeared for half the day. It's HOT again in Portland, so I only made two attempts to coax him back into the house before I was driven inside by the heat.
David came home in the early afternoon, found Sam hunkered down under the back deck, coaxed him out far enough to grab him, and he's now safely back in the house.
But it's clear he hasn't given up on the idea of going outdoors AT ALL.