I remember the first time I saw hummingbirds in a feeding frenzy right before a storm hit.
We were on a balcony of a condo in Park City, Utah. A whole bevy of them rushed to the feeders.
I have seen this often in Green Valley when we have our summer rains.
The best feeder, IMO, is the small cup. Food is always fresh. If you remember to fill it every other day or more. No ants. The hummers love it and room for only one at a time so I also have the larger feeder up for the others to fight over. The hummingbirds we have here in summer are the Broadbilled, the Black chinned and the Annas. The Rufous come through in August and fight the rest away.