One of the last things one might expect to see on a newly-exposed grassy field in the middle of March is a caterpillar crawling along. This would be unexpected because most moths overwinter as eggs or pupae inside cocoons, not as caterpillars (larvae). Most moths, but not all. Some species of moths overwinter as larvae (and adults).
Tiger Moths (and Tussock Moths) overwinter as caterpillars and pupate in the spring before emerging as adults during the summer. One member of the Tiger Moth group that is familiar to many is the Isabella Tiger Moth, known as the Woolly Bear (Pyrrharctia isabella) in its larval stage. Another member of this group that overwinters as a caterpillar is the Great Tiger Moth (Arctia caja). As early as mid-March you can find both of these caterpillars wandering in search of a protected spot where they will form hairy cocoons that surround and protect their pupal cases. The pictured Tiger Moth adult (Great or Garden Tiger Moth) bears the white geometric stripes that give the members of this group their common name.