Some people seem to think butterflies are born in spring or summer, but there are many species that overwinter as adults and come out again in spring when it is sunny enough.
These butterflies usually are damaged, from last year's encounters with hunting birds and dragonflies, from fighting with other butterflies over territoria and females, and from wear and tear from flapping about.
Here's one of those I saw yesterday:
Olympus Stylus 1s, 300mm, ISO125, f8, 1/500s
It's a comma (Polygonia c-album), gehakkelde aurelia in Dutch (for the Dutch audience: deze is behoorlijk gehakkelder dan normaal).
Despite the damage, they can still fly very well, apparently they can compensate for the missing bits without any problem.
For comparison, here are two photos of younger specimens:
Olympus Stylus 1s, 300mm, ISO200, f5.6, 1/500s
Olympus Stylus 1s, 300mm, ISO125, f4, 1/500s
Don't feel sorry for the oldtimers too much though; they may be damaged, but they can still do what they came for.