About a fifth of all the butterfly species in my area are summer migrants, although there is scientific debate about calling this dispersal vs migration. Not all migrants get here each year. When they do, populations can vary significantly. I never see more than a handful of this fritillary, but was lucky enough to find beautiful specimen while visiting a recently seeded meadow full of blooming wildflowers! And butterflies!!! This fritillary's host varies, but violet species and passionflower are top in the list. I was surprised to see Mayapple noted too. The species spends winters from Virginia and south, so this is like a reverse "snowbird" for butterflies (snowbirds are retirees that flock to Florida and other southern states for winter). It's Euptoieta claudia on Heliopsis helianthoides.