Get at least 1 star on all levels in Seasons Episode 2 Season's Greedings (Levels 4-1 to 4-25).
If you have problems with any level you can check the 3-star guide from the angrybirdsnest link below. There are 25 videos so I won't embed them here. (Note that this is not for the Trilogy version so there can be some differences on some levels)
http://www.angrybirdsnest.com/category/walkthroughs/angry-bi...