Mexican Gray Wolf Population Continues To Grow

The wild population of Mexican wolves saw another year of growth in 2023, according to the results of the annual survey. The 2023 population census revealed a minimum of 257 Mexican wolves distributed across Arizona and New Mexico. This increase marks the eighth consecutive year of population growth, the longest continuous streak since recovery efforts began.

The 2023 population minimum count represents a six percent increase from the minimum of 242 wolves counted in 2022. Survey results show the population is distributed with a minimum of 144 wolves in New Mexico and 113 in Arizona.

“In the aggregate, the 2023 data points out that Mexican wolf recovery has come a long way since the first release,” said Jim deVos, Arizona Game and Fish Department Mexican Wolf Coordinator. “Each year, the free-roaming Mexican wolf population numbers increase and the areas they occupy expands. Genetic management using pups from captivity is also showing results. In total, 99 pups carefully selected for their genetic value have been placed in 40 wild dens since 2016, and some of these fosters have produced litters of their own. While recovery is in the future, examining the last decade of data certainly provides optimism that recovery will be achieved.”

Mexican wolf population information is gathered from November through February by the Interagency Field Team. During this time, the field team conducts ground and aerial surveys, using a variety of methods, including remote cameras, scat collection, and visual observation. Counting the population at the same time each winter allows for comparable year-to-year trends at a time of year when the Mexican wolf population is most stable.

Among the 2023 findings:

• A minimum of 56 packs were documented at the end of 2023: 36 in New Mexico and 20 in Arizona. A wolf pack is defined as two or more wolves that maintain an established home range.
• A minimum of 138 pups were born in 2023, with at least 86 surviving until the end of the year (a 62 percent survival rate). In general, wild wolf populations have an average survival rate of 50 percent for pup survival in the first year.
• A minimum of 26 breeding pairs (15 in New Mexico, 11 in Arizona) was recorded in 2023.
• There were 113 collared wolves in the wild at the end of the year, which is 44 percent of the minimum population of Mexican wolves.

The field team documented additional success with fostering efforts in 2023. To date, a minimum of 15 fostered Mexican wolf pups have survived to breeding age, and at least ten fostered wolves have successfully bred and produced litters in the wild. Fostered Mexican wolves have produced more than 20 litters and several of those offspring have gone on to produce pups of their own.

“It’s encouraging to see success across the board with our recovery efforts,” said Brady McGee, U.S. Fish and Wildlife Service Mexican Wolf Recovery Coordinator. “Having fostered Mexican wolves survive, disperse, pair up, breed, and start packs of their own tells us that fostering is working. These genetically diverse wolves, which came from captivity as pups and were placed into wild dens, play a vital role in boosting the genetic diversity of the wild population.”

The Mexican wolf is listed separately from the gray wolf as an endangered subspecies under the federal Endangered Species Act. In 1977, the Service and its partners initiated efforts to conserve the subspecies by developing a bi-national captive breeding program stemming from just seven Mexican wolves. Mexican wolves were first reintroduced to the wild in 1998.

In addition to the minimum wild population, there are approximately 350 Mexican wolves currently maintained in more than 60 facilities throughout the United States and Mexico under the Mexican Wolf Saving Animals From Extinction program.

Partners in Mexican wolf recovery in the United States include the Service, Arizona Game and Fish Department, New Mexico Department of Game and Fish, U.S. Department of Agriculture (USDA) Forest Service, USDA APHIS Wildlife Services, White Mountain Apache Tribe, Bureau of Land Management, National Park Service, and the Saving Animals From Extinction program.