Not the past 5 to 10 years

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Posted by Ballpark Frank ( on 00:45:28 08/01/17

In Reply to: Wildlife, elk and bison posted by Richard Maggard


First, regarding bison, there is only one pack in the park, the Mollies, who spend part of the winter in Pelican Valley, that prey on bison with any regularity, and that is primarily in winter, after the elk have migrated out of the area. When the wolves were reintroduced in 1995 and 1996, the USFWS and their counterparts in Canada deliberately targeted wolf packs that lived in bison country, and were known to prey on bison regularly. The hope that this might help exert some control on Yellowstone's bison population. This strategy, while well-intentioned and well-reasoned, has largely been a failure. Bringing down bison is tough, dangerous work. It's much easier to hunt elk, and the wolves figured that out real quickly.

Second, regarding bison, the annual bison census numbers do not support your observation. The IBMP (Interagency Bison Management Plan), which has been in effect since 2000, calls for management actions in any year that the bison census reflects more than 3,000 bison within the park boundaries. The IBMP was created in response to a federal court ruling on a lawsuit filed by the State of Montana, driven by a concern that the state might lose its brucellosis class-free status if infected Yellowstone bison were allowed to roam free outside the park, where they might infect livestock with the brucella abortis bacterium. Last year's bison census pegged the herd population at 5,500, which triggered substantial removals when many of those bison migrated outside the park this past winter. The repeated culls have been ongoing over the past 17 years. The numbers are public information, available online, and speak for themselves.

The bison rut has started. I saw large numbers of bison in Little America on Saturday, and today, large herds were torturing motorists in Hayden Valley. I had long waits southbound in the afternoon and northbound in the evening. The herd appears to be doing quite well.

As far as elk are concerned, the picture is much more confused, as Hoot alluded to. Considerable research was conducted in the wake of wolf reintroduction to study their impact on the Yellowstone elk herd. The results showed a serious initial impact by the wolves. It was like they had been air-dropped into a smorgasbord. We saw phenomena unheard of prior to the Yellowstone reintroduction. We saw cases of multiple female wolves having large litters within the same pack, when ordinarily, only the alpha female reproduces. This is one of the behaviors seen in coyote populations that are under pressure by humans and other threats. In the case of the wolves, they were responding to the abundance of food. In 2000, the Druid Peak pack had 3 litters, with 21 pups. The pack population grew to 27 wolves. A year later, it was 35. Then, as predicted by the biologists, the pack splintered into multiple packs, and a few wolves dispersed, eventually either forming a new pack or joining a pre-existing pack. The research showed that grizzly predation on elk calves is a serious factor in elk numbers decline. We have also seen behavior changes in the elk. Rather than hang out in large herds, out in the open, where we can see them, and so can the wolves, many elk now exist in small scattered herds. There was a time when the National Park Service was trapping and transplanting elk, and eventually, just simply killing what they considered to be surplus elk. Then the special additional winter elk hunt was added in the area near Gardiner as a means of trimming the overpopulation. It appears that the elk numbers have stabilized at between 8,000 and 10,000 animals, which is considerably lower than what existed before wolf reintroduction. The Northern Range, which was considered overgrazed by many people back in the 1950s-1990s is undergoing significant changes in the aftermath of wolf reintroduction. Research on that impact is ongoing.


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