1. Science, education, and wolf conservation
John A. Vucetich, Ph.D.
School of Forest Resources & Environmental Science
Michigan Technological University, Houghton, MI
9/19/2018
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Isle Royale (544 km2)
Thunder Bay, ON
Lake Superior
Sault Sainte Marie, MI
Houghton, MI
Duluth, MN
9/19/2018
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3. Template copyright 2005 www.brainybetty.com
Wolves are recovering.
Scientists have been studying wolves for some time.
What insights can scientists offer efforts to recover and conserve?
9/19/2018
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4. Q1: How many deer do wolves kill in a year
Q1: How many deer do wolves kill in a year? Q2: What kind of prey do wolves kill? Q3: How do wolves affect deer abundance?

5. How many prey do wolves kill?
1) Two ways to express the kill rate:
# of kills per wolf per month.
# of kills per pack per month.
2) Across North America ~160 estimates of kill rate different places ~90 of these estimates come from Isle Royale.
3) Kill rate is almost always estimated during winter.
4) Know virtually nothing about kill rates from March through December.

6. Kill rates: Isle Royale wolves & moose
Jan. & Feb. of: 1971
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

7. Kill rates: Isle Royale wolves & moose
Jan. & Feb. of: 1971, 1972
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

8. Kill rates: Isle Royale wolves & moose
Jan. & Feb. of: 1971, 1972, 1973
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

9. Kill rates: Isle Royale wolves & moose
Jan. & Feb. of:
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

10. Kill rates: Isle Royale wolves & moose
Jan. & Feb. of:
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

11. Kill rates: Isle Royale wolves & moose
Jan. & Feb. of:
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

12. Kill rates: Isle Royale wolves & moose
Jan. & Feb. of:
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

13. Kill rates: Isle Royale wolves & moose
Kill rates are EXTREMELY variable.
Jan. & Feb. of:
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

14. Kill rates: Isle Royale wolves & moose
Kill rates are EXTREMELY variable.
Maximum kill rate is 2-1/2 times typical kill rate.
Minimum kill rate is 15% of typical kill rate.
Jan. & Feb. of:
Kills per wolf per month
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

15. Kill rates: Isle Royale wolves & moose
Kill rates are EXTREMELY variable.
Maximum kill rate is 2-1/2 times typical kill rate.
Minimum kill rate is 15% of typical kill rate.
Jan. & Feb. of:
Kills per wolf per month
When times are good (25% of the time), wolves get 2-4 times more food than when times are bad (25% of the time).
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

16. Kill rates: Isle Royale wolves & moose
Kill rates are EXTREMELY variable, and only partly predictable.
Kills per wolf per month
wolves 0.17
unknown 0.54
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)

17. Isle Royale kill rates (Jan-Feb), 1971-2000
Kill rates are EXTREMELY variable, and only somewhat predictable.
Isle Royale kill rates (Jan-Feb),
Kills / wolf / day
minimum (15% of typical)
lower quartile 0.59
median 0.86
upper quartile 1.2
max 2.3 (2-1/2 times more than typical)
R2=0.34

18. Kill Rates for Upper Michigan Wolves: group of ~30 wolves in packs of size 2-6 in U.P.
Brett Huntzinger 2005

19. Between January and April, kill rate can vary five fold!
Brett Huntzinger 2005

20. Kill Rates Kill rate varies from year to year.
Kill rate varies from month to month.
Kill rate varies with moose, wolves, snow, prey vulnerability
Very little idea about summer kill rates.
Kill rate studies tell us VERY little about the effect of wolves on prey abundance.
We cannot answer the question: how many prey do wolves kill in a year?

21. Prey selection What kind of prey do wolves kill?
If wolves primarily kill prey that are old, weak, or vulnerable to death from some other cause, perhaps:
wolves will have little effect on prey abundance,
wolves will cull genetically inferior prey,
reduce rate of death due to starvation.

22. Prey selection By the 1970s, we knew (3 things):
1) Wolves test moose before killing them. They kill only 1 in 20 that they test. Wolves cannot kill 95% of the moose they encounter.

23. Prey selection By the 1970s, we knew:
2) About ½ of all the adult moose that wolves kill on Isle Royale have something seriously wrong with them (starving, jaw necrosis, arthritis).

24. Prey selection By the 1970s, we knew:
2) About ½ of all the moose that wolves kill on Isle Royale have something seriously wrong with them (starving, jaw necrosis, arthritis).

25. Prey selection By the 1970s, we knew:
2) About ½ of all the moose that wolves kill on Isle Royale have something seriously wrong with them (starving, jaw necrosis, arthritis).

26. Prey selection By the 1970s, we knew:
3) Wolves prefer to kill calves and old prey.
Peterson 1977

27. Prey selection By the 1970s, we knew:
3) Wolves are usually only able to kill calves and old prey.
Peterson 1977

28. Prey selection More recently…
Ages of elk killed by hunters and wolves in Yellowstone.
Greg Wright 2003

29. Prey selection More recently…
Ages of deer killed by cars and wolves in Michigan.
Huntzinger 2005

30. Prey selection What kind of prey do wolves kill?
Wolves primarily kill prey that are young, old, weak, or vulnerable in some way.
Perhaps:
wolves affect prey abundance less than would be suggested by kill rate,
wolves cull genetically inferior prey,
reduce rate of death due to starvation.

31. Wolves & prey abundance
How do wolves affect the abundance of prey populations?

32. Wolves & prey abundance – Isle Royale
After the Isle Royale wolf population crashed in 1980 and remain low for a decade (due to disease), moose abundance increased dramatically.
Moose
Wolves
Year
9/19/2018
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33. Wolves & prey abundance – Isle Royale
Think about all the fluctuations in moose abundance. Can we explain those fluctuations? What causes those fluctuations? wolves, food, climate?
Moose
Wolves
Year
9/19/2018
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34. Wolves & prey abundance – Isle Royale
After watching for nearly 50 years, we still can’t explain a significant portion of fluctuations in Isle Royale moose.
Of the influences we can identify, climate is most important, and wolves are least important.
spring
Thank you for your interest in the wolves and moose of Isle Royale.
My discussion today consists of two portions:
First, I’ll discuss the natural history of wolves and moose.
Then in the second part of this talk, we’ll look at the research techniques and findings that are particular to Isle Royale.

35. Wolves & prey abundance – Yellowstone
wolf reintroduction

36. Wolves & prey abundance – North America
Prey abundance determines wolf abundance.
9/19/2018
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37. Wolves & prey abundance – North America
Predators determine prey abundance.
40 studies:
-- moose (26)
-- caribou (7)
-- elk (6)
-- bison (1)
N = 18
N = 17
N = 15
9/19/2018
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