Signing: Make the bird sign by making a beak shape with your index finger and thumb by bringing those two fingers together, while making a mini-fist with the rest of your fingers. Then tweet like a bird, by bringing your fingers together and apart.
This is one of my favorite signs!
Usage: When you see a bird point it out and make the sign for bird. I often add a tweeting sound effect to the bird sign, to make it a little more fun.
Flash Card: Click the link to view the Bird Baby Sign Language Flash Card. The flash cards are printable and available in both U.S. Letter and A4 sizes.