Unlike the Spring songbird migration, which comes in giant waves, Fall migration is scattered and gradual. I've seen a few fall warblers in recent days (difficult to identify because they are so drab), and our Catbirds have departed.
As in Spring, small birds (Passerines and the like) migrate at night.
For birders, the cool thing in Fall are the hawk, eagle, and, to some extent, owl migrations. They are daytime migrants. Our breeding Ospreys left last week, headed mostly for the Caribbean.
Actually, not sure about how owls move south but they do not do extensive migrations.