In my dream kit birds would be much more interactive. The way I see it you could have smaller birds that function like the My First Pets so interactions would be limited to things watch/treat but then I would have much bigger birds like parrots and crows which is where thegameplay comes in!
I see them functioning like a cross between chickens and cats/dogs. So they would be tied to a cage but you could allow them to Free Fly (the sim takes them outside/a large area for a fly around), send them to their cage or 'Free Roam'. Because larger parrots/corvids seem to spend a majority of their time walking/climbing rather then flying I see them roaming about your house like chickens (except they would eat from pet bowls, sleep in small pet beds and climb cat towers!).
Also give them a skill tree!! So talking to a parrot would increase social needs for adults/children (maybe telling them jokes would increase comedy skill too) and also build the parrots communication skills. At high level they would be able to repeat some simlish phrases and also talk to toddlers to increase their communication skills.
Clearly I have thought about this waaaaaay too much!LOL
But its past time we had another gameplay kit and so why not make it a good one!!