As a young art student, Phyllis Shafer had been told that painting outdoors, or en plein air, wasn’t for real artists; only hobbyists set up an easel pondside on a Sunday afternoon. So she stayed inside for years, first in New York City and then in California’s Bay Area, conjuring fantasy landscapes—until a show by a group of plein air artists inspired her to begin capturing real habitats outside. She’d then return to the studio to add her characteristic whimsy. “I’d just rather start my paintings from life than from a photograph,” Shafer says. It’s how she cultivates her passion for ecosystems and wildlife: “Loving and engaging in nature is the first step toward stewardship." It proved trickier to capture the fine details of flitting birds. Some of Shafer’s earliest avian paintings were of Tree Swallows. The birds swooped around a cottonwood she captured in person, but she didn’t try to incorporate the birds while outside. At home she looked up pictures of...