Instructions
Pull back the slingshot so that your first bird flies well over the second tower -- holding the slingshot at an angle slightly less than 30 degrees will suffice. Tap anywhere on the screen to drop the bird's egg just as the bird passes the second tower. The egg will destroy the pig immediately to the right of the tower, and the second and third towers will collapse, killing the other pig on that side.
Shoot the second white bird at the same angle, and drop its egg between the two pigs that sit to the right of the first tower. At least one of the pigs to the right of the tower will be destroyed.
Sling the third bird, a yellow one, at such an angle that it flies nearly vertical. Pull the band of the slingshot down so that it is parallel with the wooden post that holds it. Release the slingshot and just as it begins to pass over the first tower, or what remains of it, tap the screen to speed up the bird on the way down. The last two pigs are destroyed and you still have one red bird left. If the yellow bird does not kill one or more of the final pigs, shoot the red bird at the same angle as the yellow bird so that it comes down on the remaining pig.