Grind level 1-8 to build your total. You get four birds that are made for destroying ice and nearly all ice blocks to break. Tap to split the bird into three before it makes contact to increase your effectiveness. Pause and restart the level to repeat when there are not many ice blocks remaining. You can get at least fifteen blocks destroyed with each attempt of the level, netting about one hundred per minute. Level 1-11 may be better, but you get less splitting birds to work with.