Wolves and Deer:  Fact from Fiction

In our neck of the woods wolves are allowed to roam their territory under the proviso of local citizens that nothing goes wrong - even the perception of it.  Take for example the wolves I study, the Fishtrap pack.  It was rumored several years ago that these terrestrial piranhas had eaten all the deer in a nearby valley, which apparently didn’t leave much for the bears, cougars, and coyotes that lived there as well. 

I hear about this misperception every year.  Even a forest gnome, such as myself, knows that deer are as common as dirt in our area.  At the time, an outfitter friend remarked that ungulates were in record numbers as evidenced by the unusual number of deer and moose sightings in which the females were accompanied by more than one calf.  “They don’t have much pressure on them from predators this year,” concluded my professional hunting friend.  Even the coveted elk herds were doing well.  By the way, his information was similar to the conclusions found by the scientific studies regarding the population trends of ungulates in Montana.  Nevertheless, the Fishtrap pack apparently had rendered the neighboring valley “deer-less.”  There were survivors but not nearly enough to hunt in the fall, which was the real issue.

Despite the persistent rumor that the Fishtrap pack kills more and more deer annually, I wondered if some of our local citizens may have had a point, so I turned to my wolf study for some answers.  When I survey for wolves each day, I keep track of all the wildlife I encounter along my routes.  This includes deer, elk, moose, bears, and other assorted creatures.  From June 1, 2004 to June 1, 2005, I recorded over 600 sightings of deer in the “deer-less” valley alone.  During this time the wolves were not particularly active in this area so neither was I.  However, I occasionally traveled through the valley to get from one area to another which only took about ten minutes.  Nevertheless, I still saw a great number of deer, and this didn’t include the hundreds of deer prints I recorded during the winter.  Granted some of these were repeated sightings, but given the logic of some locals, I apparently saw the same five deer over 600 times.

There seems to be plenty of deer in our nearby valley along with all the other species of ungulates, such as elk and moose.  These are not official deer counts, of course, because I am not conducting a deer study.  They are only to give myself a relative idea of the prey base available to predators.  However, it is still better than a guess and my conclusions coincide with the current scientific literature.

I also hear from people who are concerned that wolves will reproduce like lemmings, and eventually we will soon be up to our armpits in wolf packs.  The biology of wolves doesn’t work this way.  In fact they have their own versions of population control.  Let’s use the pack I study as an example.  In 2005, the Fishtrap pack had only 2 - 3 pups, while the year before there were seven.  Despite the number of pups, however, the number of wolves in the Fishtrap pack has remained fairly constant, from 7 - 12 wolves annually.  This is because pup mortality can be high in wolf packs, up to 50 percent.  In addition, some individuals, called dispersers, leave the pack to strike out on their own.  Wolf packs also defend their territory from intrusion by other wolves.  In this case their territory size is about 370 square miles.  The net result of all these processes is that within a pack’s territory there is rarely a large increase in the number of wolves.  So when community members let me know when they have seen wolves, over time they are seeing the same ones over and over.

This brings us back to the first point which is how many deer can a wolf pack possibly eat within their territory?  As you can imagine, this is greatly dependent on the number of deer present.  Even if they ate one deer a week that would only be 52 deer each year.  We all know there are more deer than that, even to the point of having to avoid them with our cars.  The shear number of deer in our area produces plenty of road-kill deer, apparently the ones who have suicidal tendencies.  We’ve all seen them.  Some just stand at the road edge and sigh, and they wait for the right moment to step into oncoming traffic.  Or perhaps they are the individuals who know they will be eaten anyway and are just tired of “running.”  And we have all witnessed the X-deer, who for sport think they can reach the other side of the road before the semi arrives.

So do wolves kill all the deer in northwest Montana?  No.  In fact it is deer that we are up to our armpits in.  The wildest rumor I’ve heard so far takes into account this biological tendency.  Apparently some enterprising auto insurance companies have released wolves into the forest so they will chase deer onto the road only to be hit by unsuspecting motorists.  So be aware of the Allstate pack.  They’ll be the ones with bumper stickers on their butts that say, “Sponsored by the Committee of Stupid Rumors.”

2/25/08