Snug in a Snag

If a big tree dies in your yard, sometimes it’s best to cut it down. You don’t want it to topple over and crash into your house, a person, or a pet. But if a big tree dies in the forest, often it’s best to leave it be.

Biologists call a dead tree that’s still standing a snag. Lots of animals call it home. Snags provide nurseries, hiding places, and food to a variety of critters, from itty-bitty bugs to big black bears.

Let’s peek in on a few cavity creatures who think dead trees are the bee’s knees.

Cavity Crafter

Woodpeckers raise their babies in holes they hammer into trees. When excavating a nest cavity, the chisel-beaked birds search for soft wood that is already dead or rotting. As you might guess, snags are perfect. After the woodpecker family moves out, other critters move in. Squirrels, bats, screech-owls, wood ducks, and bluebirds are just a few of the animals that make their homes in abandoned woodpecker holes.

Snack Storage

Snags offer a handy place to stash snacks. Squirrels, chipmunks, and red-headed woodpeckers hide acorns in hollow snags. Nuthatches, titmice, and chickadees wedge seeds into a snag’s cracks and crevices. In fact, chickadees hide so many seeds in the fall, their brains actually grow bigger in winter. The extra brain space helps them keep a mental map of where they hid their snacks. In spring, when food is more plentiful, their brains shrink back to normal size.

Leap of Faith

Most ducks nest on the ground, but mama wood ducks raise their babies in holes high up in trees. About a day after they hatch, the fuzzy ducklings follow mom to the front door of the treehouse and bail out. Wheeeee! The little fluff balls furiously flap their stubby wings, but they can’t fly yet. Luckily, ducklings are nearly as light as cotton balls, so they tumble down and bounce off the ground without getting hurt.

Hideout for Baby Bandits

In April and May, mama raccoons give birth to babies, called kits. Like many mammals, the newborns — usually three or four per mom — are completely helpless. They can’t even open their eyes until they’re about three weeks old! To keep her babies safe from owls and bobcats, mom hides them away, often in a hollow snag. The kits stay in the den until they’re about 9 weeks old, when mom begins teaching them how to climb trees and find food.

Snuggle Buddies

Southern flying squirrels can’t pack on fat for winter like most mammals. They have to stay lean to glide from tree to tree. So when temperatures plummet, they crowd inside cavities to keep warm. The body heat from several forest flyers can raise the temperature inside a snag by up to 30 degrees, and the more snuggle buddies there are, the toastier it gets. Fifty flying squirrels have been found packed inside a single tree!

Snug as a Bug in a Snag

Some mama beetles tunnel into trees and lay their eggs inside. When the baby beetles hatch, they’re hungry. The white, wormlike larvae wiggle beneath the bark, munching on wood as they go. Nom, nom, nom. Their eating sprees leave behind squiggly paths, called galleries, that become visible when sections of bark slip off of a snag.

Now You See Me. Now You Don’t.

After a hard night of hunting, an eastern screech-owl just wants some shut-eye. To hide from hungry hawks and fussy songbirds, the sleepy owl crawls inside a tree cavity and closes its big yellow eyes. The camouflage pattern on its feathers makes the little owl all but invisible against a barky background.

Bedroom for a Bear

To pack on fat for winter, American black bears gobble down acorns, insects, and whatever else they can get their grubby paws on. At the peak of their feast-fest, they may gain 40 pounds in a week! When they’re sufficiently chubby, they waddle to a cozy spot — like a hollow snag — curl up inside, and take a looong winter nap. While snoozing, black bears go nearly 100 days without eating, drinking, or going to the bathroom.