I use 1/3 cup white sugar and 1 cup water in my feeders. I re-fill them after a rain or if they have gone a week with out changing. If you put in too much sugar you’ll have yellow jackets all over your feeders and the hummingbirds will avoid them.
Put your hummingbird feeders up high. The males will fight over them and come close to the ground while fighting. This makes them prey for cats if the feeders are too low.
Atty. Donald Burger has the dates listed back through 1993 of the hummingbirds arrival in the spring and the fall. March 23rd is the earliest spring migration he records and Aug 3rd is the earliest fall migration he recorded.
He also notes the spring migration lay over here is much shorter than the fall.
The local expert on hummingbirds has told me this is the book to get if you want to know more about Texas hummingbirds: Hummingbirds of Texas: With Their New Mexico And Arizona Ranges (Tam Nature Guides)