2nd Try

Setting for the background

Just a simply set up for the background, it's only playing with gradient. I didn't change the screen size, 640 x 480 I think it's enough for prototype.

Add character

I added in an edited yellow bird image which I downloaded it from Google onto the scene.

Adjust the setting of the character

I adjusted the collision of the character, I don't want too much space around the character.

Add trees

Insert trees into the scene

 I added the tree onto the scene and duplicate many of them to make it looks nicer. I also adjusted the collision around of the trees like I did it to the bird.

Set up all action for the character and trees.

I added the action script into the character (bird) to allow it to flap when player press space bar.

Add gravity into the scene

I also added some gravity to let the character fall after flaping.

Here is the prototype, click here to download.

There's some error in the prototype, because it's kinda lagging when I opened it, will try to solve the problem.