Mexican Wolf
Southwest Region Ecological Services
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Mexican wolf pups huddle in the den. Credit: USFWS.
Mexican wolf pups huddle in the den. Credit: USFWS.
The Mexican Wolf Reintroduction Project

Reintroduction of the Mexican gray wolf was initiated by the U.S. Fish and Wildlife Service in March 1998. Mexican wolves living in the Mexican Wolf Experimental Population Area (MWEPA) are designated as a nonessential experimental population which allows for greater management flexibility to address wolf conflict situations such as livestock depredations and nuisance behavior. The MWEPA is a defined geographic area that encompasses Arizona and New Mexico from Interstate 40 south to the international border with Mexico.

Middle Fork AM871 investigates a food cache with a bear. Credit: Mexican Wolf Interagency Field Team.
Middle Fork AM871 investigates a food cache with a bear. Credit: Mexican Wolf Interagency Field Team.

The Mexican Wolf reintroduction project is managed by the U.S. Fish and Wildlife Service in collaboration with the following cooperating agencies: Arizona Game and Fish Department, USDA Forest Service, USDA-APHIS Wildlife Services, and the White Mountain Apache Tribe. These agencies, along with the Arizona Counties of Gila, Graham, Greenlee, and Navajo, and the Eastern Arizona Counties Organization work together under a formal Memorandum of Understanding which provides a framework for collaboration that is based in sound science and which enables the signatories to develop a mutually-agreeable, long-term collaboration in reintroduction of Mexican wolves in Arizona and New Mexico within the Mexican Wolf Experimental Population Area as defined in the 2015 Final Rule governing reintroduction.

Reintroduction of a top predator such as the Mexican wolf is highly complex and often controversial. It is important to understand the role Mexican wolves are playing on the landscape, including all of the potential biological, social and economic impacts - be they good, bad, or indifferent. In order to continually evaluate this role, an Interagency Field Team (IFT) has been formed and has the primary responsibilities of collecting data, monitoring, and managing the free-ranging Mexican wolf population. Equally important is the IFT's close interaction and involvement with local communities directly affected by wolf recovery.

Mexican Wolf Population Information

2016 Mexican Wolf Experimental Population Area Summary

At the end of 2016, at least 114 Mexican wolves occupied the Mexican Wolf Experimental Population Area (MWEPA). This represents a 16.5% increase from the 2015 minimum population estimate of 97. Fourteen of the twenty-three packs documented in the MWEPA exhibited denning behavior and pups were observed in all fourteen packs. A minimum of 65 pups were documented during the year, with a minimum of 50 surviving in the wild at year's end. Eleven of these packs met the definition of breeding pair at the end of 2016. All packs at the end of 2016 were formed naturally in the wild.

Fourteen natural pairings of breeding age wolves in the MWEPA population occurred in 2016. The natural pairings of dispersing or single wolves resulted in the designation of two new packs, Baldy and Leopold. Six new pairs formed during 2016; however, only three remained by the end of December. In addition, breeding animals were naturally replaced in six other packs.

At the conclusion of the 2016 end-of-year count, 54 of the documented 114 wolves in the MWEPA, were equipped with radio collars (48% of the known population). Many of these wolves were fitted with GPS/ARGOS satellite telemetry collars. These radio collars use satellite technology to record accurate wolf locations on a frequent basis. This information can be used by biologists to gain timely information pertaining to many facets of wolf behavior such as dispersal, territory use, predation data, and denning behavior.

The IFT conducted three cross-foster events involving three packs, resulting in the initial release of six neonatal wolf pups. Two pups were introduced into each of the three dens. Each den initially contained five wild-born pups; the addition of two cross-fostered pups resulted in each of the dens having a total of seven pups after the operation. All of the cross-foster events were initially considered successful (pups from captivity were introduced into wild dens; the event did not result in the abandonment of the den), and some pups survived in each of the dens until the late fall and early winter. Two cross-fostered pups were confirmed alive at the end of 2016 and others may have survived in each of the cross-fostered packs.

A Luna pack wolf in the winter of 2011. Credit: Mexican Wolf Interagency Field Team.
A Luna pack wolf in the winter of 2011. Credit: Mexican Wolf Interagency Field Team.

The IFT documented 14 mortalities of free-ranging wolves in 2016, including 9 adults, 3 subadults, and 2 pups. This in an 8% increase from documented free-ranging wolf mortalities (13) in 2015.

Home ranges were calculated for 20 packs or individuals exhibiting territorial behavior. The 95% fixed kernel method produced an average home range size of 255 square miles, with home range size varying from 78 square miles to 858 square miles.

Native prey utilized by wolves consisted primarily of elk; however, there were also 50 confirmed fatal livestock depredations.

In 2016, the IFT analyzed 72 reports of wolf sightings from the public; 88% of these reports were non-wolf sightings (coyote, dogs, etc.), while 12% of these reports were determined to be Mexican wolves. The IFT searched 16 areas in the MWEPA for new wolf presence and 11 uncollared wolves in the MWEPA were documented. As a result of these efforts nine wolves where included in the annual population count.

Mexican wolf project personnel provided a total of 24 presentations and status reports to approximately 1,000 people in federal and state agencies, conservation groups, rural communities, schools, wildlife workshops, and various other public, private, tribal institutions throughout Arizona, New Mexico and White Mountain Apache Tribal lands. Ninety-two percent of the presentations were for the MWEPA target audience. In addition, biweekly contacts were made to cooperating agencies and stakeholders to inform stakeholders of wolf locations Mexican wolf reintroduction project updates were emailed to an average of 18,287 people a month.

Definitions Breeding pair: a pack that consists of an adult male and female and at least one pup of the year surviving through December 31. Cross-Foster: the removal of offspring from their biological parents and placement with surrogate parents. If the offspring were in captivity at the time of the removal this is also an Initial Release.

Additional information about the Mexican Wolf Reintroduction Project can be found on Arizona Game and Fish Department's web page at: .

Mexican wolf experimental population map
Download copy of Mexican Wolf Experimental Population Map. USFWS.
Map of recent wolf locations
Recent Wolf Locations (ArcGIS)
Download Mexican Wolf Home Range map.
Mexican Wolf Recovery Area Population Estimate - 12/31/2017
Last updated: August 21, 2019