We asked bird bander, Meret Wilson, from Ormond Beach, Florida:
How do you know if you are seeing a ruby-throat hummingbird migrant?
I watch the behavior of my overwintering hummingbirds. Their "hummer fights" will indicate a new intruder has arrived. My males that have overwintered here look a bit shaggy at the moment, but the new migrants that will show up, most likely late March to early April will be shinning with new fresh alternate breeding plumage.