Jerry demonstrated the first use of his new sign language word - "more", which he does by bringing his hands together (after making a cone with each hand.)
I think this is quite noteworthy because it is the first use of an action or feeling rather than just a noun.
Jerry does have signs for plane, gorilla, bird, and hat: plane is where he holds his hand up high over his head; for gorilla he beats his hands on his chest (or more typically, his stomach); for bird he moves his pointer and thumb together (like beak); for hat he hits his head with his hand.
This little guy is growing up so fast. He's such a good natured kid - I really enjoy spending time with him. We went to the park tonight and I found out he was able to cross the wooden bridge by himself - and he went on the big slide for the first time by himself too!
Wow.