Do you have any oak trees in your yard? Go out and look on the ground. (We’ll wait.)
Did you see any acorns? “The Washington Post” reports that there aren’t any. Not in the D.C. area, but also not in Pennsylvania or New England. (They don’t have much data from other regions, which is why I am asking you.)
This seems to be true of all varieties of oaks (red, white, etc.). And climate, weather, disease, parasites and other possible suspects don’t seem to explain it. See this.
The oaks are in no danger, according to the experts, but it is making the squirrels very hungry, which, in turn, is making them act, well, squirrellier.