It is that time of the year, or at least almost that time of year. Watch for wet trees.
Here in Iowa most of the trees are deciduous. The leaves fell from the branches last year, and the sap is starting to flow. There can be wounds in the bark or near the branches–caused by wind, heavy snow, even mammals like fox squirrels. When that happens, sap flows down the tree trunks.
These small holes were caused by a sapsucker (a small woodpecker).
Insects, including butterflies, are attracted to the sap.
I should note that it is extremely rare to see wild butterflies in February in Iowa. But it did happen last year. And I think it could happen this year, also. Possibly as early as this Friday, if the forecast is to believed.
So if you see a wet tree trunk, look closely. You just might see a butterfly. Mourning cloaks and eastern commas are the most likely.