The Wild Side: Carnivores are coping with winter
The activity in the woods takes on a different complexion this time of year. Many of the wildlife species that inhabit the Northwoods are changing their typical behavior. For many fur-bearing wildlife species, mid-February signals the start of the breeding season. This is a group of animals that grow fur, multiple hairs extending from a single follicle instead of a single hair per follicle like typical humans have. I use the term fur-bearer freely, but I have been trying to switch to calling them carnivores. The name fits; not because they are strict meat-eaters, as many (like black bears) have varying diets. In fact, it is because the cat family (Felidae), weasel family (Mustelidae), raccoons (Procyonidae), bear family (Ursidae), and dog family (Canidae) all belong to the same general order called Carnivora.
Our large carnivore populations are the highest they have been in recent history. In addition to the common carnivores, like raccoons, foxes and coyotes, we have seen greater numbers of bears, wolves and now even cougars (pumas) in the state than we had a half-century ago. From a natural resource management standpoint, these animals, the carnivores, are managed similarly, but the group is handled differently from deer or small game. Small game species (with the exception of migratory waterfowl) see consistent, standard harvest limits and seasons. But furbearers, carnivores, are more intensively measured and managed. I am not going to talk about deer. They are a huge topic for another article. The carnivores are harvested either by trapping, hunting or both. We collect parts of the harvested animals to examine their age structure and reproductive history. We run survey routes and record presence or absence data on them all. Typically, though, we need to finish our snow track surveys by now because their behavior changes.
Wolves are a good example. In mid-January, I ran a route in western Oneida County where four wolves walked abreast down a gravel road. I doubt any wildlife manager in Wisconsin’s history thought we would see that in the 21st century. There were so many tracks from previous days that it was hard to sort them all out. In February, I ran a route where I know we have wolves, and did not document a single wolf track. They have not left; they have altered their behavior. The alpha (top dog) pair is probably focusing on pair bonding and preparing for mating as the female’s reproductive cycle prepares to begin. A month ago, they were patrolling pack boundaries, defending their territory, looking for food; now they are likely keeping closer to a preferred den site, clearing snow and debris away. They still protect their turf and look for food, but they clearly cover less ground than earlier in the winter.
Other canines, like coyotes and wolves, are mating and denning as well. Raccoons are breeding too. Felines have a more variable breeding window, but it still falls in late winter; bobcats tend to begin breeding after mid-February. The weasel relatives breed a year in advance; fisher and otter bred in March or April of 2012 will give birth next month. The black bear, our largest current resident carnivore, is a notable exception-they breed in June, and right about now they are giving birth to their cubs in the den.
So, whether related to denning and breeding or not, carnivores are generally in a mid-winter pattern of reduced activity. Nights are very cold; the snow is usually too deep to get around easily. Small, light prey animals escape quickly either on top of snow or by tunneling under it. For the animals that use water, like mink and otter, the rivers are getting pretty iced up, making water access difficult. Much like many humans, carnivores are reducing their activity level, heading out only to conduct essential life business. They are going to need a lot of energy soon to tend to their young.
Jeremy Holtz is a wildlife biologist with the Wisconsin DNR and writes a weekly column in the Star Journal. To contact him, call (715) 365-8999.