robotic bird....as i think thats the route were taking, someone said puppets, but thats risky, because frankly actors cant be trusted to know there parts, let alone to move the bird independantly.
You know the first instances of "Animatronics" were in Ancient Greece. Herron of Alexandria,
http://www.britannica.com/eb/article-9040189, constructed a tree full of golden little birds. Their Beaks would open and close as a cacaphony of trilling whistles and chirps emanated from the
base of the "sculpture". He also built the very first automated scenery, an entire shows worth. It ran on Grain and sand and pulleys and cogs and knotted ropes, and gravity. What I'm trying to impress upon you is this, if you lived in ancient Greece, and you had lots of time afforded to you by your class as an aristocrat I would say by all means
build a robot. Heck I've built robots for displays, they are expensive, tend to be noisy, and they break a lot. On the other
hand Actors can be quiet < they can, I've seen it > they are extremely cheap < beleive me I know my first girlfreind ... Never mind. > and if they break, they are really easy to replace.
In the immortal words of somebody, K.I.S.S. < keep it simple and stupid > (
see most people think it's <keep it simple, stupid> I prefer it the non aggressive way and honestly it means a lot more because you should keep it simple and stupid , easier to fix that way)
Build a robot in your spare time. I suggest scraping a few cheap-o radio control cars for you first endeavors. or check out the books on this link,
http://www.powells.com/s?kw=robotics It's fun and you'll learn a lot.