Northern IL pollen!

Maple, maybe.

I bet maple too. Shows to be the predominant pollen for your zip code.

http://www.pollen.com

And the color looks to match pretty good.

http://en.wikipedia.org/wiki/Pollen_source

Hear in central IL i was watching some pale yellow pollen being brought in today.
not as bright yellow as in your pic

I'm not sure, but my 2 hives were coming back yesterday late afternoon with bright yellow pollen as well.

The likely suspects are silver maples and a couple of kinds of willows. Those are the only things I know of blooming yet that might have pollen for the bees.

Aspen catkins are out, too, but aspen is a wind-blown pollen, and I don't know if the bees would work it. I'll have to stand under an aspen and try to see if I see any bee activity -- shouldn't be hard, I've got one at the back of the yard (I love it, despite the fact that they're considered a "junk" tree -- such pretty leaves that flutter in the softest breeze, and nice fall color).

i've got the same color pollen in syracuse and no maples open yet, must be skunk cabbage or something similar because only the hives that I have in the river valleys have any coming in. two weeks earlier than last year. I just saw my lawn today.