Butterflies are ectotherms, meaning they rely on external sources to stay warm. They love being in the sun as much as possible! Having a rock in the full sun gives the butterflies a place to rest and warm up their bodies. You’ll see them with their wings wide open, soaking up the sun. Besides a rock for basking, they should also have a shallow pan to drink out of, like this bee bath. All pollinators will love it! For the butterflies, be sure to add some sand or gravel at the bottom, so it’s not too deep.