Last spring, three kits were born in a fox den visible across a ravine from my driveway. I watched the early progress through binoculars: the kits nursing, sunning themselves, playing, and frantically diving for cover if a large bird sailed overhead.

Fancying myself a latter-day Saint Francis, I decided to befriend them. I took daily walks in the vicinity of the den, whistling softly and leaving small gifts—a bone, a raw egg, a handful of cat food. Purists frown on such interference with nature, I know, but I figure houses like mine, built in the foxes' territory, have already disrupted the natural order.

The first few weeks the kits scrambled into the den whenever they saw me. As they grew accustomed to my presence, though, they retreated to rocks nearby. They peered at me inquisitively, golden eyes alert, ears twitching to every sound, their unscarred red coats glistening in the sun.

Eventually the three began following me. I felt like the Pied Piper. If I stopped, they stopped and hid behind a rock or bush. If I ran, they ran too. If I sat for a picnic lunch, they surrounded me. Once I tossed an apple core into some bushes and in a flash all three pounced. Quivering, frozen in a hunting posture, they waited, and I realized that they were waiting for it to move, like all their food.

As the Colorado summer progressed, I would stand in my driveway and whistle; on command, the three handsome young foxes came bounding across the ravine. They stalked butterflies in a patch of wildflowers. They gave futile chase to wily squirrels. They stood on their hind legs and lapped water from our birdbath—once jumping back in alarm when a skim of ice reflected their own images.

In order to keep the deer, elk, and rabbits out of ...