In central Texas, where I live, we're blessed with ruby throated hummingbirds during the summer. I put my feeders up in March. I usually see the first hummer before the end of the month. This year we had a very unusual snow fall on April 9, and I had a LOT of hummers at my feeder. I spent my lunch hour at home putting up two more feeders. I've had a little more activity this summer than normal. I suppose that means that fewer people in my immediate area are hanging out feeders.
The southern migration started not long ago, and my regulars have gone. I think I saw the last hummer about three or four days ago. I leave the feeders up for those who are passing through until at least the end of October. That's probably too long, but I want to make sure that the migrating hummingbirds find the nectar. I'm going to miss them, as I always do during the fall and winter.
If you're interested in learning about hummingbirds, start here: http://www.hummingbirds.net/ .