Cottontail numbers double, predators savouring boom

TheStar.com - GTA - Cottontail numbers double, predators savouring boom
July 16, 2008
Nick Kyonka
Staff Reporter

An explosion of Toronto's cottontail rabbits may be just what the doctor ordered for some ailing predators that are still struggling to recover from a deadly outbreak four years ago, conservation authorities say.

The reasons for that explosion: the ideal spring and winter weather and the timing of bunnies' natural population cycle.

"I'm sure we're into the tens of thousands," says the Toronto and Region Conservation Authority's Ralph Toninger, of the cottontail's numbers.

"They're probably at double the population they were at last year."

Like many other wild animals, the rabbits have a natural population cycle that sees their numbers rise and fall at fairly regular intervals based on the number of predators and the availability of food.

For the cottontails, the population peaks roughly every seven or eight years, Toninger says, noting the last time they reached such high numbers was around the turn of the millennium.

This year's weather has also been ideal for the quick-footed critters, which thrive in snowy winters because they can easily evade heavy-footed predators on light-lying snow.

"Rabbits will stay on top of the snow to find food and can burrow down inside of it for warmth and protection after," Toninger explains.

They have also, no doubt, enjoyed the lush vegetation that has accompanied this year's wetter-than-average spring.

And thanks to their ability to "breed like rabbits", Toninger notes, "if it's a late fall, their numbers could easily keep increasing as the summer goes on."

Female cottontails can bring a pregnancy to term in just six weeks, allowing them to breed four or five times per breeding season, with as many as six bunnies per litter, he says.

Eventually, however, the population will outgrow available food sources – mostly leafy plants and the bark from small fruit trees – and their numbers will start to dwindle again.

In the meantime most people need not worry about the newly abundant rabbits, Toninger says, since they are not dangerous and don't carry any significant diseases.

And though the rabbits will probably be a source of frustration for avid gardeners, they are also a vital source of food for stealthy predators such as foxes and coyotes, whose numbers were cut by an outbreak of mange about four years ago.

While agile hunters, coyotes and foxes struck by the disease lost significant amounts of fur, making them unable to survive the winter.

But with all the extra rabbits hopping around, the recovering predators are having an easier time pouncing on a meal, Toninger says.

"They're just now regaining their numbers," he notes. "Which is important for the balance of the local ecosystem . . . It's all part of the natural cycle."