Tim Van Deelen, Associate Professor
Department of Forest and Wildlife Ecology
UW-Madison College of Agricultural and Life Sciences
Tim Van Deelen tells us the fate of Wisconsin’s wolf population
3:12 – Total Time
0:20 – How wolves die
0:44 – New research findings
1:45 – Careful observation needed
2:35 – The deer
3:03 – Lead out
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Sevie Kenyon: Can you give us an idea about the lifespan of a wolf and what typically ends their lives?
Tim Van Deelen: Well as far as we know from radio collaring date, wolves die from a variety of reasons. Quite often they’ll get hit on the road. Wolves are also territorial, so on the margins of habitat where there’s territorial disputes between packs, wolves will kill each other. Wolves die of disease- we’ve had wolves sometimes starve to death.
Sevie Kenyon: Tim you’ve done some research, can you tell us anything new or different that you’ve found?
Tim Van Deelen: The basic populations dynamics equations is very simple. It says that the number of animals born minus the number of animals dying is the net addition or subtraction from the population. So if we have a population that we can count every year like we do with wolves, we count them every winter, then we can mathematically fit an equation to that using things like observed deaths and estimated reproduction. And when we can’t get that to reconcile, then we need some additional deaths, which are unobserved, to make the growth rate that we see agree with the mortality and the reproductive rates that we’re measuring. And the suspicion is that some of those unobserved deaths are illegal killing, because we do from our radio tracking data, have good estimates on the relative amounts of deaths that are due to these other things—like being killed by other wolves or dying of disease or being hit on the road.
Sevie Kenyon: And Time, what would you like to see done with wolf management going forward?
Tim Van Deelen: Well one of the very neat things about wolf management in Wisconsin is that we’re managing this population now at a pretty high exploitation rate. Meaning that we’ve got heavy harvest seasons. Those are designed implicitly to reduce the wolf population. Harvest management theory would suggest that there’s some danger of long-term instability. I think that the most important thing with the managers of Wisconsin’s wolf population need to do is to keep putting efforts into monitoring the wolf population. Tracking population trend, tracking the extent to which wolves live on the landscape, those are going to be the two measurements that you’re going to be able to use to identify you know some sort of instability, and then be able to deal with it.
Sevie Kenyon: What kind of conflicts do people have with wolves here in Wisconsin?
Tim Van Deelen: There’s a lot of talked about wolves having impacts on deer. You know in some places that’s probably a reality, and some places it might be more perception than reality. We actually don’t find a whole lot of wolf predation on adult deer; which would be the mechanism by which wolves would have the most impact on the deer herd. Which isn’t to say, you know, if you’re the unlucky individual whose hunting for it happens to be sitting right on top of a wolf rendezvous, then you might not be seeing many deer.
Sevie Kenyon: We’ve been visiting with Tim Van Deelen, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, and the College of Agricultural and Life Sciences, and I am Sevie Kenyon.