Great point, Iowa Roo Mom. Sick, homeless cats are a threat to the health of everyone's pet kitty that has access to outside. I personally keep mine inside 95% of the time but I know there is a risk that, even with me being in the yard supervising them, they could come in contact with a stray cat. Cat fights are not pretty.
We lose many songbirds to roaming cats but any cat let outside will hunt what it can, even if they're not hungry. Hopefully they stick to mice and lizards but not always...