When the mice move in looking for a warm place to overwinter, the poison under the sink has a second victim list: everything that eats mice. Anticoagulant rat poison doesn't kill fast. It stops blood from clotting, and a poisoned mouse staggers around for days before it dies, slow and out in the open. That makes it the easiest meal in the neighborhood for an owl, a hawk or a fox, and they take the whole dose. When researchers at Tufts tested red-tailed hawks brought into their wildlife clinic, every single one had rodenticide in it. Hawks, eagles and owls are routinely found bleeding to death internally from mice they caught. Kill the predators and the mice come back faster, into a yard with nothing left to hunt them. These tips work better than rodenticide: 1. Seal the gaps. A mouse fits through a hole the width of a pencil. 2. Put away the pet food and birdseed. That's usually why they came in. 3. Use live traps to humanely catch and release any mice that get in, then repeat steps 1 and 2. That mouse could be an owl's next meal. 4. If live traps aren't an option, use snap traps inside, set in covered boxes so pets and kids can't reach them. They kill in seconds and the body stays where you put it. Outside, leave the job to what eats mice for free. A barn owl family can take more than a thousand rodents a year. An owl box does more for your mouse problem than the poison aisle ever will.