I live in the Sierra foothill community of Oakhurst, California elevation 2,500 ft. Very dry, very hot summer. I live on an acre that abuts 70 acres. Recently moved my three feeders from central courtyard area to the outer side of my carport. Suddenly I went from maybe a dozen to at least a hundred hummers. Mix of Rufus and Annas. Is there any issue with this large of a population in one area. They are as grouchy as ever but are begrudgingly sharing. Don't mind keeping up with the sugar water supply but can they survive on only sugar water? I don't notice them flying off for bugs (I'm working in the carport).