I noticed that house finches (this is probably the same with gold finches) eat sunflower seeds by spinning them around in their beaks while biting down rapidly to get the shells off, then eat the inside and drop the shell. Or at least that’s what it looks like, evidently they have a groove in their beaks that they maneuver the seed into then use a few movements to slice and husk the seed (way cooler than what I thought originally!).
Titmouses (Titmice?) and chickadees eat the seeds in a similar way. Chickadees and titmouses will toss some of the (possibly too big?) sunflower seeds to the side but pick out one to eat now and then. To eat it they’ll place the seed by their feet and peck at the shell to get it open.
I don’t get to see other birds at my feeder nearly as often so that’s all I have to say on that… Though on the topic of birds I would also like to appreciate all the mourning doves who have tried their best to eat from my bird feeder, sat right in front of my porch, and laid an egg on my fence.
so you figured this all out just by watching your bird feeder? that's really cool!!