This morning we found that someone had left us a partially eaten robin on the driveway.
I don't know if it was a gift or a threat. Usually when our cats brought us dead or mostly-dead critters, it was interpreted as a gift, we praised the cats highly, and then told them they could eat the whole thing because (regretfully) we were already stuffed full of inferior food.
To me, the ex-robin said, "Hello, I'd like to join your household, please."
But I'm aware that it could also be the alley cat equivalent of finding a horse's head in my bed.
When I got home tonight the carcass was gone.
More on this situation as it develops.