Thanks CyberKitten!
Stanley's been to the vet twice already. The first time was because he was sick when we first got him. :sad: Last night was just a checkup. The vet said Stanley was in great shape.
I simply forgot to mention this behavious to the vet as I had so many other questions I wanted to ask.
That said, I don't think it's a medical issue. I really don't know how he made the noise... maybe it was while sniffing, as you said. I just mistook it for a bird chirping outside at first... it was very faint.
You mentionned soft grinding of the teeth. I noticed this when I pet him (he
loves to be petted... and I love petting him!). He always looks like he's enjoying it... I guess now I know he does.
Now that we're sure that Stanley's a boy, the vet was able to explain everything I should know about neutering yesterday and gave me an estimate. He will be neutered when he's 6 months, so around mid-February.
Thanks so much for your help (and the great link!). I really appreciate it.
I'm such a worrywart when it comes to Stanley's health and happiness.