Why the rabbit population is peaking in the suburbs

In recent months, I have heard folks comment on the abundance of rabbits in their yards. Eastern cottontails, our resident rabbit species, use habitats that can be found almost anywhere.

Cottontail friendly terrain includes grassy, weedy, and brushy areas such as old fields, farmsteads and suburban habitats.

This prolific species usually has three or four litters per year, with four to six young per litter. Every 10 years, more or less, the rabbit population reaches a peak that is eventually brought down by disease and strife. Locally, we seem to be reaching one of these cyclic population highs. When the rabbit populations near their high, many carnivores are licking their chops.

For predators, rabbits are the original fast food. Simply put, everybody eats them. The list of those who like to find a hare on their plate includes fox, coyote, bobcat, weasels, hawks, owls, snakes, and so on. To put it another way, just think of rabbits as nature's popcorn.

So what do rabbits eat?

In spring and summer, there are a lot of green plants on the rabbits' menu, including grasses, legumes (e.g. clovers), plantains, dandelions, goldenrods and, of course, garden vegetables.

As summer turns to autumn, cottontails will enjoy ripening and falling fruit, whether it be wild crabapples or domestic corn. When winter arrives, rabbits will nibble on the buds, twigs, and bark of woody vegetation such as brambles, dogwoods, and maple trees.

Rabbits need some help in digesting their vegetarian diet and that is where gut inhabitant mutualism comes in. Now that's a mouthful, isn't it?

Much as we benefit from probiotics, cottontails require a healthy population of microbes in their gut in order to help completely digest their plant diet. Like all of us, rabbits excrete their digested food. Some say cottontail droppings look like raisins, but I think dark-colored M&M's is a better description.

These pellets contain the microorganisms that aid the rabbits' digestion. So what do the cottontails do when healthy bacteria exit with their feces? They snack on their own M&M's.

Before leaving this excursion into vegetarian dining, we need to explain the term mutualism. This refers to the mutually beneficial relationship between the microbes and the rabbits. The bacteria get a nice, warm place to live with plenty to eat while the rabbits benefit from the extra nutrients the bacteria release from the leaves and twigs the cottontail has ingested.

I know there are gardeners who'd rather not see a cottontail. By and large, rabbits avoid smelly, prickly, or thick leaved plants. Here are a few species that rabbits aren't too fond of: black-eyed Susan, yarrow, lupine, bee balm, pachysandra, crocus, iris, dahlia, and daffodil.

Trees that aren't on the rabbits top 10 list include juniper, redbud, hawthorn, pine, spruce, and oak.

An effective cottontail barrier would be a three-foot-tall chicken wire (one-inch mesh or smaller) fence around your garden. Since rabbits can dig, make sure an additional six inches of mesh is buried in the soil.

Odor repellents (e.g., powdered fox urine) can also be used. When it comes to urine, you might want to go straight to the manufacturer and get a dog. But then, you may soon be wandering through the neighborhood looking for your dog who took off after the rabbit.

• Mark Spreyer is the executive director of the Stillman Nature Center in Barrington. Email him at stillnc@wildblue.net.