Rabbit Madness
By Marilyn Shy
I first noticed it about mid-summer, though it could have been going on for a bit longer.
Rabbits seemed to be invading my yard in record numbers. And everyone I talked to seemed to be having the same problem. It wasn’t just my little neighborhood near Rainbow Jim Bridge. The same situation was reported to me by my friends in the UP. And when I took a week long bike ride along the White Pine Trail, from Cadillac to Grand Rapids, I saw dozens of bunnies on the trail daily. They seemed to be everywhere. I cannot remember seeing so many in one season.
The final piece of evidence occurred over several days in July, when my entire marigold bed got wiped out. I like to grow the taller variety that are 2-3 feet in height with large carnation-like flowers. This year, for the first time, the bunnies were managing to eat the entire plant, which is easily 3 feet taller than they are. How do they do it? Well, with their sharp front teeth they cut down the stems, one by one, then they proceed to eat every single leaf and flower, leaving only the skeleton-looking stalks behind. I could find nothing to deter them, not even the Deer-B-Gone spray I faithfully applied night after night. Bunnies were winning the war this summer, and nothing I could do would prevent their voracious appetites from taking down plants they usually avoid.
So why were their numbers so high this year?
It turns out that animal populations fluctuate on a regular and predictable basis. This is largely due to predator-prey cycles where a delicate balance exists. Eastern cottontails, our most common rabbit, are the prey species of a number of predators, including coyote, fox, bobcat, hawk, and Great-horned Owl. Let’s take coyote as an example. The population on each side of the relationship, for instance, rabbit (prey) and coyote (predator) is dependent upon the size of the other. When there are lots of rabbits (coyote food), then in a little while there will be a boom in the number of coyotes. After a while, they will drive down the number of rabbits. After that, the number of coyotes will drop, as they are competing for a smaller number of animals and their food supplies become scarce. And then the rabbit population rebounds, because there are less coyotes, and the cycle repeats itself.
Sometimes there are unpredictable population explosions or collapses, and the length of time between cycles can change as well. This can be due to disease, weather or other factors.
Warmer winters and shorter winter seasons can affect animal populations, including those of rabbits. Seemingly small changes can lead to higher than average reproductive rates, and ultimately have profound effects. In Michigan, most rabbit breeding takes place from March through September. An adult female rabbit ordinarily has 3-4 litters per year with 3-8 babies per litter. But they can have up to 7 litters per year, depending on food availability and amount and quality of escape cover. Females from the first litter can breed that same summer since rabbits can begin breeding at 2-3 months of age. So if the season is extended even a few days on either side, the rabbits may begin breeding like…..well, like RABBITS!
Since weather can affect cover, it can also affect the number of rabbits that can survive in each litter. The better the cover, the more babies will survive. In rainy years, the cover can be remarkably better than in dry years. Have you noticed this year that the grass and shrubs were amazingly more green and lush? I certainly noticed it.
The actual length of the population cycle for cottontails is not well understood, with some claiming it is 3-5 years long, and others thinking it is more like 8-10 years. I believe this year we hit the “perfect storm” for rabbit populations, with a natural high point in the cycle along with favorable weather conditions producing extra litters and good cover favoring high survival rates.
In any event, the population of rabbits is likely to crash soon. So my advice to gardeners is: Put up a secure rabbit fence for now. And try to enjoy those cute little critters that are part of the changing landscape in our astounding and beautiful natural world.