I think Ryan's pretty much right on.
I see you're in the very SE corner of the LP, probably very similar weather/ temps. to what we're having here in far NE IL. You're right off of Lake Erie, we're right off of Lake Michigan.
Our danelions are blooming, yours probably are too. I would say if you notice the bees aren't taking as much (or maybe very little at all) of the sugar water it's OK to take it off. If they're still sucking it down, let them, leave it on. As long as you don't have honey supers on, you're fine.
If all (or nearly all) of the wax foundations in the brood boxes are drawn out, they really have a good start. If only half or less of the foundations are drawn, you might want to leave the feeder on for another week, check the frames then and decide whether to keep on or take off at that time.