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Idaho study finds mountain lions kill more elk than wolves

Mountain lion study

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Idaho’s mountain lions play a bigger role in the overall mortality of elk than previously thought. Wolves have often been linked to poor elk calf survival rates; however, that blame may be misplaced. A new study, which was published in the Journal of Wildlife Management and analyzed 15 years of wolf and elk population data, The Spokesman-Review reports.

“Things are usually more complicated than one thing,” said Jon Horne, lead author of the paper and senior wildlife research biologist at the Idaho Department of Fish and Game. “But it’s sometimes really hard to show that.”

The study also identified harsh winters and lack of food as additional factors for elk calf survival—not just depredation. Yet, the finding that mountain lions killed slightly more elk than wolves was the interesting discovery. According to The Spokesman-Review, wolves were linked to “32% of identified mortalities for female elk” while mountain lions “accounted for 35%.” The difference was even greater when looking at elk calf survival: 28% of elk calf deaths were linked to wolves while mountain lions accounted for 45%.

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“The one variable that mattered the most for calf survival was how big it was,” said Horne, who acknowledged that the bigger the wolf pack, the larger impact on elk survival and added that was “by an amount that was not insignificant.” However, because mountain lions are typically solitary hunters, researchers couldn’t look at that same variable as they could with wolves. 

Deep snow also had a great impact on elk mortality because, according to Horne, “snow makes for harder, longer winters” and “because wolves have an advantage in deep snow.”

Horne believes the study’s findings could also apply in Washington, Montana and Canada.

This study is the second one to be published by Horne that looks at wolf impact on wildlife in Idaho. In the previous study, which was also published by the Journal of Wildlife Management, Horne discovered that the average wolf pack size stayed about the same between 2005 and 2015, despite Idaho’s legal hunting season.


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Kyle G. - posted 5 months ago on 08-13-2019 10:10:45 am
Ozark, MO

I'd be interested in knowing the population of both mountain lions and wolves in Idaho. Are wolves half the population size of mountain lions and still killing almost the same amount of elk?

Clark S. - posted 5 months ago on 08-13-2019 06:11:10 am
Albuquerque, NM

Both the Spokesman and this article cite the wrong paper by Jon Horne. The correct paper is Horne et al, 2019. Unfortunately it's behind a paywall, but the abstract does report the same numbers.

The incorrect article is Horne et al, 2018, which is about statistical modelling and data management.

Dustin F. - posted 5 months ago on 08-11-2019 03:30:25 pm
Carmel Valley, CA

Thanks for the article Mrs. Schmitt. I appreciate your journalism.

Dustin F. - posted 5 months ago on 08-11-2019 03:28:53 pm
Carmel Valley, CA
matthew a. - posted 5 months ago on 08-06-2019 02:59:17 pm
Tampa, FL

And yes, I read horne report and nothing / zero mention / of the inferrence made in the headline that mnt kions kill more elk than wolves.

Furthermore, Hornes study identified that wolf harvest doea not reduce wolf numbers.
,However, it is important to realize that even when harvest is additive, this does not necessarily mean harvest will reduce population size because abundance is also a function of recruitment. We observed a decrease in pack size after harvest was implemented, but this effect was short‐lived; pack sizes returned to pre‐harvest levels as harvest rate declined. Thus, the level of harvest may be more important for understanding the effect of harvest on wolf populations than simply whether or not there is harvest (Adams et al. 2008)."

And "Effective wolf management requires that agencies have management prescriptions that can be easily implemented, have a significant effect on populations, and whose outcomes are predictable."

matthew a. - posted 5 months ago on 08-06-2019 02:34:23 pm
Tampa, FL

I would love to see the quantifiable data. If you dont show your homework then the article and opinion of the researchers is inadmissible.

There is a TV program proving bigfoot lives. They have degrees and cinducted research so it must be true.