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State and Federal Agency Justification for Limited Mexican Wolf Range Challenged by Preeminent Group of Scientists

A wolf, whose neck extends downward from the upper left corner of the frame, places her mouth close to one of her pups' mouths to feed it.

This is post 4 of 7 in "Mexican Wolf Recovery Plan."

Throughout this series, we will follow the progression of the U.S. Fish and Wildlife Service's proposed Mexican Wolf Recovery Plan, which ignores the best available science about the population sizes and habitat areas essential to recovery. You will learn more about changes to the USFWS plan, our suggested improvements to the plan, and how you can help. All posts in this series…

Phoenix, AZ (October 4, 2017) – A new letter written by eight internationally-respected scientific experts, published in this month’s Journal of Wildlife Management, directly challenges the information relied on by state and federal wildlife agencies to limit the recovery range for Mexican wolves in the United States. The newly published work provides significant evidence that the draft Mexican wolf recovery plan, released in June, requires revisions to be scientifically credible.

The new analysis, entitled “Defense of an Expanded Historical Range for Mexican Wolf: A Comment on Heffelfinger et al.” rejects conclusions reached in previous work by Jim Heffelfinger and colleagues that adjusted Mexican wolf ‘historic range’ southward, primarily in Mexico. This now-questionable conclusion provided justification for agency officials to eliminate consideration of northern habitat deemed essential to Mexican wolf recovery by three decades of credible scientific analysis.

“Independent scientists and conservationists expressed concerns that the science being used to justify habitat range in the draft Mexican wolf recovery plan would lead to flawed management—these concerns are echoed in this new analysis and cannot be ignored by agency officials in charge of drafting the final plan,” said Kim Crumbo, conservation director for Wildlands Network.

The new analysis cites overreliance on field observations of Mexican wolves after the species was already in significant decline; failure to incorporate the most up-to-date genetic testing which is commonly used in species research; and dismissal of suitable habitat modeling in light of changed conditions in both the United States and Mexico since the extirpation of the Mexican wolf in the wild, as reasons why the prior research published by Heffelfinger and colleagues is not reliable for guiding management decisions.

These potential flaws in the science used to support the draft Mexican wolf recovery plan’s elimination of recovery habitat north of Interstate 40 in Arizona and New Mexico are especially troubling, and were raised by others during the comment period on the draft plan, which closed at the end of August.

In his comments on the draft recovery plan, Dave Parsons, a nationally-recognized wolf expert who serves as carnivore conservation biologist for The Rewilding Institute and science advisor for Project Coyote, noted that “suitable habitats necessary for recovery of Mexican wolves lying north of I-40 in the US have been unscientifically and politically excluded from consideration and must be reconsidered.”

Another key rationale for limiting the Mexican’s wolf range, included in the refuted analysis of Heffelfinger and his colleagues, to areas south of I-40 was concern about “genetic swamping” of Mexican wolves by larger wolves from the Yellowstone region, which could make their way to southern Colorado. However, the newly published critique explains that historically large intermixing zones likely existed between sub-species of wolves across North America, requiring proper management, but not the exclusion of Mexican wolves to the detriment of long-term recovery.

“The authors provide a solid, scientifically credible critique of the flawed interpretation of ‘historic range’ that excludes from a recovery plan two of the three core areas identified by the scientists as essential for Mexican wolf recovery—the Grand Canyon and northern Arizona/southern Utah core area and the northern New Mexico/southern Colorado core area,” said Wildlands Network’s Crumbo. “This is a recipe for the extinction, not recovery, of the Mexican wolf.”


Project Coyote promotes coexistence between people and wildlife through education, science and advocacy.

Wildlands Network envisions a world where nature is unbroken, and where humans co-exist in harmony with the land and its wild inhabitants. Our mission is to reconnect, restore, and rewild North America so life in all its diversity can thrive.

The Rewilding Institute develops and promotes the ideas and strategies to advance continental-scale conservation in North America.

Western Wildlife Conservancy works to protect native large carnivores and other species, and their habitats, through education and advocacy.


Kim Crumbo, Wildlands Network, 928-606-5850,
Dave Parsons, The Rewilding Institute/Project Coyote, 505-908-0468,
Kirk Robinson, Western Wildlife Conservancy, 801-468-1535,

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