Our strategy for Birdday Party (Birthday Party) level 18-3 is to launch the White bird as low as possible, but still clearing the balloons to bomb the TNT on the left. The stones and bird should launch into the main structure, pushing it to the right. Loft the next White bird over the structure and bomb to the right of the next-to-last vertical support — directly above the last pig. Use the first Yellow bird horizontally, just above the pillar, to clear all pigs in the interior. Use the final Yellow bird as necessary. The score in the video below is 69,680.
hit the edge of the wood, bird go to the left, activate tnt
second lower to push the structure
third for the last bird
here my video: