There are 4 black birds and a Rio logo formed out of blocks and 12 pigs hiding inside it.
How to get this egg:
Go to level 13-12.
Throw the first Yellow Bird anywhere.
Now zoom out. You'll see a step-like thing. Throw the White Bird back and at timing, lay an egg and you'll get the egg if you aim it right.
- The level references Rio.
- The Golden Egg was also mentioned in the promotional trailer for Rio.