Out of the corner of my eye, I noticed Chewy staring at something yesterday. When I looked over, I saw this...

Mina will talk to the birds. She has a distinct vocabulary just for them. Probably saying something like "I bet you taste good and someday I'll find out".

Oh yeah, Chewy was chattering at the robins in the yard this afternoon...

Often wonder if that chattering is a demonstration of frustration knowing the "prey" is out of reach. The cats I know that go outside seem not to do that when stalking something.

I believe it probably is. He doesn't do it when "knows" he can reach them. For example, when I let him out and there's prey around, he shuts up and goes in to stalker mode. But when they're on the roof taunting him while he's outside, he does the chattering...