How much did they actually eat, and how much did they throw on the ground while trying to find the good stuff?

That IS a blue jay. In fact, West of the Rockies it's the only blue jay.

That's why I use safflower seeds exclusively.

I had to take the bird feeders down. Birdseeds were left untouched for too long. Since the cats roam the gardens, there are no more birds here.