Because they have poor night vision, hummingbirds prefer to migrate by day. The exception is any Ruby-throated Hummingbird that lights out over the Gulf of Mexico and is over water when night falls so it must keep flying until reaching land (about 18 hours in good weather, up to 24 hours in bad). A migrant feeding at dusk will likely be at your flowers or feeders first thing in the morning. It will be tanking up on food before sleeping, and filling up again at first daylight before heading out.
"I may see them early in the morning at my feeders or just before dark."
Amy Evoniuk, Newburgh, IN 09/28/14
Amy Evoniuk, Newburgh, IN 9/29/14