Mitzi does it to - kind of a chirping sound. Sometimes I think she's saying, "hey, you scared me, but I love you anyway." I just received a pamphlet on cats called "True Confessions from Your Cat" and it says that when your cat chirps at you, she's REALLY thrilled with you. So maybe those sweet little sounds are a good thing - I just love the sound and, like everyone else, just can't resist petting them when they look so darned cute!