September is the month when Hummingbirds leave there northern homes and head south to their winter residence. I haven't seen a hummingbird in at least one and a half weeks. That is I hadn't... until today. Today I saw a female ruby-throat at my feeder three times, which I beleive was a migrant from somewhere further north. It is best to leave up feeders until the end of September so that any migrating hummers will be able to stop by a get a quick meal before heading further south. Sometimes people are rewarded by leaving up there feeders for migrants when a entire group of hummers stop by for a meal, and may hang around the entire day (if your lucky, maybe two days, but this is uncommon)!
I used to take down my hummingbird feeders in August, but then I learned that northern migrants are still going to need food on the trip south, and I might still see some hummers (hummers don't leave my area until the first or second week of Seotember anyways, so I don't know why I did this). Read the FAQ for when to take down your hummingbird feeders for more info. Remember... leave them up until the end of September, and you may be one of the lucky few who get an entire group for a while day!