Robert Frost wrote about a "blue butterfly day" in a poem with that very title, and in it, Frost described seeing "sky flakes," the name he gave to a bluish lepidopteran known as the Spring Azure. These small and delicate-looking insects are members of the Gossamerwing clan—more properly known as the family Lycaenidae—and they're actually pretty darn tough, since they start flying early and have to be able to role with the climatological punches. The weather today, however, was relatively mild, and the Azures were out looking for nectar and mates. Frost would certainly have been happy to see them. I know I was.