Yo ! I have set aside any other type of bird feed except for back sunflower seeds because many years ago, the bag of seeds I had bought produced infernal vines I was never able to get rid of. Long, thin, grow like hell ! Black sunflower helps many species winter over up here in chilly N- Québec. I go through two 33 lb bags per winter. Question is this : what else could I economically put in the feeder to accomodate birds that don't break up and eat whole sunflower seeds ? Would they go for cracked corn ? Any other suggestions ? Thanks for your time.