My kids and I are near the end of the 1½-mile Wood Duck Trail at the Heard Natural Science Museum & Wildlife Sanctuary in McKinney. The route meanders in and out of the woods; skirts wetlands where ducks, geese, and egrets commune; and wends past stretches of prairie with gracefully waving grasses. My daughter Susanna stops suddenly to watch a giant swallowtail butterfly flutter down, back up, and out of sight. I smile when a gasp of awe escapes the mouth that had, moments before, complained of being hot, tired, and in need of something—anything—from the gift shop. Meanwhile, Samuel is ahead of us as usual, just around the path’s next curve, the back of his head barely visible through the tall grasses. He’s been reading the warning signs posted along the trails excitedly, reminding us to “Watch out for copperheads!”—and in the process, likely scaring away this or other examples of native wildlife.