NewWest: What Happened to the Mulies and Pronghorns?

The National Wildlife Federation published a report demonstrating that Pronghorn and Mule Deer look to be in appreciable decline in Wyoming and Colorado. Looks like Sage-grouse are plummeting as well.

Habitat concerns, as well as Oil & Gas impacts, look to be among the culprits but I find it particularly interesting that the report does not consider livestock grazing.

What Happened to the Mulies and Pronghorns? – Shauna Stephenson –

A suite of habitat stressors appears to have caused a massive decline in mule deer and pronghorn herds around the border of Wyoming and Colorado, according to a recent National Wildlife Federation (NWF) report.

The herds, which tend to migrate back and forth over state lines, have encountered a number of pressures over the past 30 years, including fragmentation of habitat, disease, energy development, drought, and harsh winters.

Report: Population Status and Trends of Big Game and Greater Sage Grouse Along the Colorado/Wyoming State Line



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  1. Immer Treue Avatar
    Immer Treue

    Wolves can’t be blamed for this. Probably not enough food for lions, coyotes have been there a long time sooooooo, what is/are the variable(s) being manipulated? Weather and habitat fragmentation. It was a good read. I liked Torbet’s retort to oil, I won’t tell you where to drill, don’t tell me about wildlife.

  2. Larry Zuckerman Avatar

    I went to school with Torbit at Colorado State University and he is a pretty straight shooter – wasn’t aware he retired.

    I agree with Brian – everyone steps gingerly around the grazing issue – like they don’t want to step into something that stinks and will stick to them and attract flies. Basically cattle compete directly with antelope and mulies for food and space, plus create a demand for wildlife-killing and habitat fragmenting barbed wire fences. On the other hand, some of the irrigated forage certainly supports wildlife in addition to cattle.

  3. SEAK Mossback Avatar
    SEAK Mossback

    The most devastated range (by livestock) I remember ever visiting was BLM land while hunting pronghorns east of Clark, Wyoming (Badger Basin) in 1974. The few dabs of grass were well protected under clumps of prickly pear. Even pronghorns were not doing great as there were only 75 permits issued for a large unit compared with typically hundreds of permits for most areas that size. To untrained eyes it appeared like a case of land abuse beyond any economic sense . . . .

  4. mike post Avatar
    mike post

    I have hunted this area for almost 30 years and am also puzzled by the declines. The cattle grazing and energy production have been relatively static (but are in evidence everywhere) during that time, and while I do not discount their impacts on wildlife, the goats and deer have had dramatic population swings unrelated to any increased grazing or major expansion of energy projects. Winter kills have been devastating to these herds 2-3 times in the last 30 years.

    Pronghorns seem to be more vulnerable to subtle habitat changes and it is reflected in declining birth rates and offspring survival in many locations. Even in other areas with fewer predators and no hunting the herd growth rates often inexplicably static in some years.

    On a grander scale, Mule deer and Pronghorns are evolutionary products of a bygone era. Human development and the loss of large swaths of free range seems to impact them negatively (as opposed to the whitetail who is moving into mule deer country as development occurs and the mulies decline).

    Once again I think this points out a complexity that cannot be addressed by pointing a finger at just one highly visible culprit. Grazing and/or energy production may or may not provide a tipping point within specific habitats. Up in the Great Divide area of NW Colorado the proghorns seem happy and successful in the midst of lots of gas wells. Around Craig, CO they seem to favor ag fields and livestock pastures over open prarie. We need to know more.


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Brian Ertz