Hummingbird action at the feeders had been slow in May until somebody flipped a switch a few days ago. Here is a 30 second video of action at one of the feeders that isn’t being actively defended by a territorial male.
Gardening to attract hummingbirds, nature's glittering fragments of the rainbow
Hummingbird Gardener 
Wow, Donald! I had no idea you, or anyone in the north, got that kind of feeder-mob activity this time of year. I still haven’t seen that many competing for a feeder in August/September. My activity has actually slowed to a crawl the last couple days. I saw one visit yesterday and only a couple brief visits this morning from a male and female.
That kind of action isn’t common in May here, but it isn’t unprecedented, either. No matter what our level of activity now, we can all look forward to more action at the end of summer when the young are out of the nest and all are trying to fatten up for southbound migration!