Our “easier” strategy for Summer Pignic level 12 is to fire the first Blue bird into the hollow ice square in the top-left. This will force the structure rightward, hopefully detonating the TNT at its right. Launch the Yellow bird into the left side of the top structure. Fire the first White bird a little lower, bombing the right foot of the lower structure and ricocheting into the top structure. Use the last two birds as necessary to clear any remaining pigs.
Easier Strategy, scoring 108,030.
Higher Score Strategy, scoring 125,250.