Line a large cookie sheet with parchment paper or foil.
In a small bowl, beat egg whites, vanilla, and cream of tartar until soft peaks form. Gradually add sugar, beating until stiff peaks form.
Put egg mixture in a piping bag fitted with a 1/2" round tip, filling bag halfway.
Beginning at the head end, squeeze bag gently, moving tip in a clockwise direction to form a question mark. For lower body, continue squeezing as you move tip about 2 1/2" to the right, back left, then right again, releasing pressure as you pull tip up. Repeat with the remaining mixture.
Place chocolate pieces on head for eye and beak.
Bake at 300° for 15 minutes or until done. Turn oven off and let the cookies dry in the oven with the door closed for about 30 additional minutes.