"I was a little surprised to see a bat out in plain daylight, and in the sun, no less, not even the deep shade of the forest (or what might pass for deep shade in the leafless deciduous woods). Googling it, though, it seems this isn’t an altogether unusual occurrence. Most of our bats hibernate over the winter. In the spring, as the temperatures are just starting to rise, the nights can often still be quite cool or even freezing, even while the days are fairly warm. Early-risers may take advantage of these warmer daytime temperatures to do some foraging, choosing to sleep at night instead, at least until the nights start to warm up, too. Not only are there a lot more insects out flying during the day (if the temperature’s really cold, there might not be any insects at all at night), but it’s a lot easier on the bat, too. Once the nights are warm enough they’ll return to their nocturnal habits."
Seems that early emerging bats need to feed and the temperatures dictate when that will be.
