A graph showing peak migration times in south central PA
I posted this link last year, and thought it might be worth doing again. If you scroll down the page, the second graph shows peak migration times for different spring migrants. The second bird down below the Black-billed Cuckoo is the Ruby-throated Hummingbird. The graph is based on many years of banding data at Powdermill--a bird banding station in the mountains of southwestern Pennsylvania. The return times are a little later there (in the mountains) than for central Ohio and the Pittsburgh area.
It really shows well how long and drawn out the migration of ruby-throats is. Although the first birds may appear in the Powdermill area in early May, they don't peak until about two weeks later.
Take a look!
Here is a link that might be useful: Graph of peak migration times in the mountains of western PA