Garden Tiger Moth caterpillar (Arctia caja): Garden tiger moths love damp places, which is why they tend to be common in river valleys as well as gardens and parks. Caterpillars are active in the spring, with adults flying in mid summer. You can find the caterpillars again in the fall. They will overwinter and become active again in the spring. Photo by Heather McKee on 5/19/18 in Polson, MT.