In the damp foothills of South America’s Chocó rainforest lurks a speedy, ground-dwelling bird that only a handful of dedicated people have ever seen. Even fewer have successfully photographed the Banded Ground-Cuckoo, but that’s exactly what Murray Cooper aimed to do. “You can hear it, but to see it used to be an impossibility, almost,” says Cooper, a wildlife photographer based in Ecuador. Despite their relatively large stature—similar to the Greater Roadrunner—the Banded Ground-Cuckoo slips through the dense forest floor undetected. Their black, chestnut, and white plumage conceals them against the dark forest floor, and long legs help them chase down food. The birds’ clever main feeding strategy involves following swarms of army ants, munching on the insects and grubs that the ants disturb as they sweep the forest floor. “It's got this huge beak, and it's got these gnarly legs, and it's just quite incredible for a ground bird,” Cooper says. The Banded...