Smash 5000 wooden blocks
This will most likely be the first block related achievement you earn as wood is probably the most common material in the game and can be broken by most birds. A good level to boost this on is Level 1-19. Just fire the fire bomb bird to destroy the most wood blocks as possible. Detonate it when you think your are in the best position. Pause and restart the level after the dust settles on your first shot. You can earn around 10 blocks per attempt of the level, netting around 100 per minute. It would take about 45 minutes to grind all 5000 wooden blocks.