I have notice that when I get up and out early in the morning that the Bumble Bees are on the foliage a lot earlier then my honey bees? Now these bees were started from packages just a few weeks ago and not that strong and the mornings here in SW PA are still pretty cool (we just had a frost last week!). My only thoughts are that my bees are in the hive keeping the brood warmer till a little later when the sun has warmed the ground and air. Also does anyone have any recommendation for books that cover all of the bees/wasps/hornets on North America? Any thoughts are appriciated!