Eggs Mean Monarchs
One way to watch for monarchs is to watch for their eggs. Check your milkweed regularly. You'll know a butterfly has arrived in your region even if you never see one:

"I haven't personally seen a Monarch yet—but obviously there was at least one female!" wrote teacher Becky Collins from Nashville, Tennessee. She and her students counted 15 eggs in their school butterfly garden on Tuesday.

Image: Becky Collins