Ruby-throated hummingbird is the only species living in eastern part of the States. Normally male will arrive first in early spring and male hummer is also the first to leave in September.
I have a very busy summer this year with all backyard hummingbirds. I discovered more than 20 hummingbirds live around my backyard. I put out 4 feeders and could not keep up refilling them. Watching them chasing or fighting with each other all day long, I hope one day they will learn how to "share". Though this is not the case usually.
Lately, I found out these hummers did share the feeders. I am not sure if they have "learned" how to share or the males are gone and females and the young birds are nicer and less aggressive. The limited flower source in the end of summer might be the main reason for hummers allowing themselves to share the feeders with others. I did notice few new migrating hummers visited my feeders in September and October. Hummingbirds have to constantly feed on their way migrating to the south America. I am gladly welcoming our visitors. Whatever the reasons are, I am so happy to see them peacefully gathering at the meal time :) --- Happy Birding! - Linda