Wild Population of Mexican Wolves Grows for Fifth Consecutive Year

The wild population of Mexican wolves in the United States saw its fifth consecutive year of growth in 2020. According to the recent count, the U.S. population of Mexican wolves has increased by 14% since last year, raising the total number of wolves in the wild to a minimum of 186 animals.

From November 2020 through January 2021, the Interagency Field Team (IFT) conducted ground counts in Arizona and New Mexico that concluded with aerial counts of Mexican wolves in January and February. According to the IFT, the 186 wolves are distributed with 114 in New Mexico and 72 in Arizona. In 2019, the team documented a minimum of 163 wolves, which was a 24% increase from 2018. This population has nearly doubled in size over the last five years.

“With careful planning and using best practices, we were able to conduct the annual survey with the utmost emphasis on the health and safety of our staff,” said Brady McGee, U.S. Fish and Wildlife Service Mexican Wolf Recovery Coordinator. “Thanks to our staff’s efforts, we were able to document a minimum of 64 pups surviving in the wild last year. Pup production and recruitment in the wild population is extremely important to the recovery of this species. We are thrilled to see this number continuing to rise.”

Among the 2020 findings:

• There were a minimum of 46 packs (including new pairs) documented at the end of 2020: 29 in New Mexico and 17 in Arizona, plus five single wolves in Arizona. A wolf pack is defined as two or more wolves that maintain an established territory. By comparison, there were a minimum of 42 packs at the end of 2019.

• A minimum of 124 pups were born in 2020, with at least 64 surviving until the end of the year (a 52% survival rate). The average survival of Mexican wolf pups is around 50%.
• The IFT recorded a minimum of 20 breeding pairs (12 in New Mexico, eight in Arizona) with pups in 2020.
• There were 96 collared wolves in the wild at the end of the year, which is slightly more than 50% of the wild population. These radio collars use satellite technology to accurately record wolf locations on a frequent basis. Biologists on the IFT use this information to gain timely information about wolf behavior in the wild and assist with management of the wild population.
• The IFT documented 29 mortalities in the wild population of Mexican wolves in 2020, which is similar to the mortality rate in 2019 given the growing population.
• This year’s survey represents not only an all-time record number of wolves in the wild but also the most ever breeding pairs, wild packs, pups born in the wild, and pups surviving to the end of the year.

“Many people eagerly await the results of the annual Mexican wolf count. As has been the case for a decade, this year’s result signals success in recovery of this element of the Southwest’s biodiversity and offers hope of eventually meeting recovery goals,” said Clay Crowder, Assistant Director, Wildlife Management Division, Arizona Game and Fish Department. “With continued year-over-year increases in the United States, it is important to recognize that Mexico is key to full recovery, and more attention is needed in support of efforts there.”

In 2020, the IFT placed 20 captive-born pups into seven wild dens (a process called “cross fostering”) to boost the genetic diversity in the wild population. The IFT has since captured and collared seven of these pups and will continue efforts in 2021 to document others that may have survived. With these newly collared pups, the known number of fostered wolves alive is 12. 

The Mexican wolf is the rarest subspecies of gray wolf in North America. It is listed separately from the gray wolf as an endangered subspecies under the federal Endangered Species Act. In 1977, the U.S. Fish and Wildlife Service (Service) and many partners initiated efforts to conserve the subspecies by developing a bi-national captive breeding program with the seven remaining Mexican wolves in existence. Approximately 350 Mexican wolves are currently maintained in more than 55 facilities throughout the United States and Mexico.

Partners in Mexican wolf recovery in the United States include the Service, Arizona Game and Fish Department, New Mexico Department of Game and Fish, USDA Forest Service, USDA APHIS Wildlife Services, White Mountain Apache Tribe, Bureau of Land Management, and National Park Service.

For more information on the Mexican Wolf Recovery Program, visit the Mexican wolf website (www.fws.gov/southwest/es/mexicanwolf) or visit the Arizona Game and Fish Department website on wolves (www.azgfd.gov/wolf).