I too have noticed the lack of huimmers. My neighbor has 2 very large mimosa trees, I have lots of flowers and feeders out but until Saturday, I had not seen one for about 6 weeks. I still hve not seen any males this year. The one here a few times over the weekend looks to be a small female, maybe juvie. She is not very well marked but no sign of color on the throat so I am sure it is a female. No sign of her today though. I wondered if this high heat has any inpact on them. Paula Geihs Nelson County