Put off clearing your flower beds until warmer weather comes

You have not spring-cleaned your flower beds? Good for you! You aren’t lazy. You are a good gardener. Native insects, unlike birds, do not migrate. You and I and our native insects have survived the winter just past, you and I indoors, our native insects outdoors in our yards: below the surface of bare spots of ground; beneath leaves; inside the stalks of now-dead plants. And in those places our native insects will stay, until daytime temperature is regularly 10 degrees C. or higher. For our native insects overwintering in our yards, human tidiness is the opposite of good housekeeping. Raking your leaves too soon can expose insects too soon, including moths and butterfly larvae, which have survived winter’s deep freeze. Similarly, cutting and putting dead plant stalks in paper bags for collection on your waste collection day will send beneficial insects on a one-way ride to become compost. Returning birds, which make their nests from dead plants, tug and take stems and strappy leaves. Nest-builders choose the strong stems and leaves which require their most effort to remove.

Mourning Cloak butterfly - Nymphalis antiopa

A gardener I know reports “I wait until I see Mourning Cloak butterflies flying. They overwinter in leaf litter and it's important not to disturb them and other species that do the same. They're big and easy to recognize so they make a good indicator.”