How I got this photo: Black bear hibernates in above-ground den

My friend and I were on a late-fall grouse hunt when we stumbled upon this unusual black bear den.

When we entered the woods, shotguns in hand, the temperature was just above zero. The sun was shining brightly. The air was calm. We ambled through an oak forest — too open to hold any late-season grouse — and headed for a nearby ash swamp where we hoped the thicker cover would harbor a bird or two.

As we neared the swamp, we noticed a giant pile of grass with a black lump in the middle. It was a black bear den.

Except this wasn't the typical den. Bears normally winter underground, usually beneath the roots of a fallen tree. But sometimes they simply use their enormous paws to rake together a pile of leaves and grass, forming a huge bed. That's what this bear had done.

Then it crawled atop the pile and fell asleep.

A foot or so of snow covered the ground, yet the bear and its bed were highly exposed. It seemed the bruin had been active as of late, since the bed and the bear itself were mostly snow-free. We also spotted fresh bear tracks around the animal's lair.

As my friend and I cautiously approached, the bear's ears perked up. It heard our footfalls in the cold snow. When we moved even closer, the bear slowly lifted its head and stared at us with groggy eyes. After a few seconds, it tucked its face back into the giant nest.

Black bears are the most common bear species in North America. They store a winter's worth of food in the form of body fat. They eat like crazy during the fall, filling up on just about anything they can find: acorns, fruit, carrion and farm crops including corn. They achieve a thick layer of fat before entering a den and sleeping away the winter.

Bears are not true hibernators. Once in the den, their metabolism slows considerably, but their body temperature falls only a few degrees. The extra body fat sustains them during the long winter. Black bears occasionally leave the den and start to wander nearby, especially during warm spells.

Never before and never since have I seen a black bear den built above the ground using grass. My friend and I felt fortunate to witness such a rare display.