…even squirrels won’t eat it.

So why is it an ingredient in most packages of birdseed? Same reason as cracked corn, which squirrels will eat in a pinch but birds won’t—heft, I say, bags sold by weight, not by volume. (Theoretically, cardinals will eat safflower, but, as far as I can tell, only reluctantly.)

Here’s what I think should be in birdseed mixes, in addition to sunflower and millet:
Quinoa, rice, barley, oats, farro, milo, soy beans, bulgar, field peas, triticale, spelt, dried crabapples, and peanuts.

That would make you want to be a bird.