Jim - they may have already completed their 2nd brood in your location now and you are actually seeing some juveniles battling it out at the feeders with the females, as they look similar until the juvie males start growing their gorget "beards" and characteristic couple ruby feathers on their throats. The juvie males even have tail feathers with white tips like the females. I know I am seeing juvies out in force here after the one brood that recently fledged after my first females arrived in May.

They supposedly would have nested about 6 - 8 weeks after first arriving in spring. So if there were any females that arrived in March or April (the humminbirds.net map shows all the first sightings in Georgia having happened in mid-late March), the 1st brood might have fledged in late May and if the females could reuse a nest, a 2nd could be coming out now.

There are occassions where they can sometimes do a 3rd brood but the timing would need to be so that the babies are able to get up enough weight to go themselves in October.

Banders in S. Louisiana are seeing molting and migration beginning now, so in your case, you may be done and the ones that you have seen in fall were northern migrator juvies and females.

Thanks Jenny, it does go a long way in explaining what I am seeing. In the past, I have seen females with their baby in tow, that would hang around until late October, apparently for the newly hatched juvenile to put on a little weight. They would stay together like two peas in a pod.
I do know that I now have non-stop hummingbird activity nearly everywhere I look in my yard. The numbers that I have do not compare with some lucky people, but I have so many that I cannot count them. There is fighting and chasing everywhere with birds darting in all directions.
In the past, during this time of year, activity slowed down and did not pick up until late August or early September. What I am seeing now compares with or exceeds what I have seen during the peak of migration. I wish I could get these birds banded so that I could get an idea of approximately how many I do have. I am going through a lot of sugar water but I can't use that as a measure as they are also all feeding from the thousands of necter producing flowers from my half acre hummingbird garden of a yard.
Let the good times roll and the hummingbirds swarm.