Kenneth Quaranto, owner of KDQ Landscaping, recently got an unusual request from one of his customers – “don’t mow that spot in the middle of the lawn.”
Actually, the landowner hadn’t left anything to chance. He had erected a fence around the location.
As it turned out, the spot was home to a family of rabbits, and had it not been marked there would have been no way of knowing the bunnies were there.
Quaranto wasn’t surprised. He said he couldn’t remember a year with so many rabbits. Wherever there is green grass and shrubs, whether off a busy road like West Shore Road or a field in a rural setting, there are rabbits.
Why so many rabbits this year?
It has to do with a 10-year cycle, reasons Leland Mello, supervising biologist in the Department of Environmental Management’s Division of Fish and Wildlife. But there are other factors, Mello and other biologists say.
And then there are others who question how best to control the population and save their gardens. Mello points out that rabbits have a fondness for blueberries and raspberries.
Rob Cote – whose boasting about how he has managed to deal with pests from raccoons to squirrels and skunks ended up with a review of his claims by the DEM – called rabbits one of the more difficult of critters.
Few repellants, including the odiferous coyote urine – if you can find it – discourage them from nibbling on what they like. He suggests Repels-All and, if all else fails, finding where the rabbits nest and placing a rag soaked in Clorox to drive them away.
Rabbits around these parts are the Eastern cottontail, which is not easy to distinguish from the New England cottontail. The latter has been the subject of extensive study by T.J. McGreevy Jr., Ph.D., research assistant professor and the director of Wildlife Genetics & Ecology Laboratory at the University of Rhode Island’s Department of Natural Resources Science.
About the same size as the Eastern, the New England cottontail has a slightly different shape to its skull, said McGreevy. New England rabbit populations have declined and it is feared the species may disappear completely from Rhode Island.
While they share habitat, McGreevy doesn’t see the Eastern as edging out the New England.
Nonetheless, the Eastern population has exploded.
As Michael Healey, spokesman for the DEM observes, “They’re breeding like rabbits.”
Although these rabbits have high mortality – with a death rate up to 80 percent a year – the species survives because they reproduce up to seven times per season, with a reproductively mature doe having from three to eight young per litter, Healey said in an email.
Mello attributes the proliferation of rabbits to a 10-year cycle, among other factors.
According to the DEM biologists, no population of organisms remains fixed or constant. Although it is not well understood, the Eastern cottontail – which is one of the most common mammals in the United States – generally experiences a population cycle with peak populations occurring at intervals of about 10 years.
The biologists say that after bottoming out, the number of cottontails will climb slowly for about five years. Once the population peaks in number, it will usually stay close to the peak for about three years. Then, numbers will abruptly fall for a couple of years due to various factors such as disease, predation and low reproduction until the population bottoms out and numbers start to climb again.
And what is the role of predators?
“The Eastern cottontail is a very important food source in our ecosystem. The population of prey affects the population of a predator directly, and vice versa, but animals have very different reproductive/breeding cycles. The main predators of rabbits such as coyotes, foxes, bobcats, fishers and others in the weasel family, and avian predators such as owls and hawks, take longer to breed than rabbits. In other words, generally, it takes time for predators to catch up to prey – but they will catch up. We don’t know when, but when they do, then we won’t see as many rabbits as we’ve been seeing lately,” said Healey in an email.
Might climate change also impact rabbit populations?
Healey said DEM is not aware of any studies that suggest a correlation between climate change and population cycles.
“It’s a fair point to hypothesize that there may be one,” he added.
He noted that locally, the effects of climate change include warmer winters and increased precipitation. The rabbits start breeding in January, and he reasoned it is possible more young are surviving because of milder weather and increased levels of vegetation, including the grasses and thickets rabbits depend on for food and cover.
“The resulting lush vegetation could be coinciding with the peak year of the cottontails’ 10-year cycle to produce very high numbers of rabbits,” he said.