Birds, even wild ones, are very picky eaters. I have discovered that, within the seed mix I give the finches, red-winged blackbirds, cardinals, blue jays and mourning doves that come to my window, they have favorite seeds, second favorites and least favorites.
Black oil sunflower seeds are sheer manna. These go first, and quick. Their shells are scattered atop all the other uneaten seeds in the feeder.
Next goes the millet. Apparently, not so tasty as sunflower seeds, but the birds can choke it down.
Then there is the milo.
Milo seeds are the black jelly beans left at the bottom of the jar, or the Special Dark chocolates in the bag of Halloween candies that the parents end up eating or throwing away. Sometimes the kids will eat them, but only after all the other treats have been depleted.
My avian guests have to eat these, though. I don't refill the feeder until most of the previous batch of feed is gone. My feeder, my rules.
Since I have discovered that bags with only black seeds are available, I plan to buy those in the future. However, the birds will have to put up with almost 10 more pounds of the mix before they go black and (possibly) never go back.