The number of reintroduced Mexican gray wolves rose by 14% in 2020, according to the U.S. Fish and Wildlife Service.
The additional 23 wolves documented in the annual population survey brings the number of wolves in the wild in Arizona and New Mexico to 186, the federal agency reported.
The November-January survey documented 114 wolves in New Mexico and 72 in Arizona. The population has doubled in size in the past 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 staffs,” said Brady McGee, USFWS Mexican wolf recovery coordinator. “We were able to document 64 pups surviving in the wild last year. We are thrilled to see the number continuing to rise.”
The report came in a court filing in which the U.S. Fish and Wildlife Service asked for an additional 14 months to overhaul its recovery plan, an effort underway since 2015.
The overhaul of the recovery plan centers on whether to significantly expand the area in which the wolves will be released and allowed to wander. A judge ordered the overhaul after finding the Fish and Wildlife Service ignored the opinions of its own contract biologists that a single recovery population would remain vulnerable to extinction — especially if not connected to a much smaller population of wolves in Mexico. Critics said the federal government should establish additional populations across most of the midsection of Arizona — and close to the Mexican border.
The increase in the number of wolves in the wild stemmed in part from an effort to place wolf pups born in captivity in the dens of wild wolves with pups. Last spring, biologists placed 20 of these foster pups in wild wolf dens. At least six of them were documented as still alive in the end-of-the year census.
“With the 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 recovery efforts there,” said Clay Crowder, assistant director of the Wildlife Management Division at the Arizona Game and Fish Department.
The report found that at least 34 wolves died in 2020, a relatively high mortality rate for a wild population. Five were killed by federal snipers after preying on cattle. Another 10 wolves were removed by federal trappers, two of which died. Another 44 wolves simply disappeared from the census count, some of them with radio collars.
The documented 27% mortality rate in the wild exceeds the USFWS target of keeping deaths below 25% of the population annually.
“It is gratifying that more Mexican wolves are roaming this little corner of the Southwest,” said Michael Robinson of the Center for Biological Diversity. “But even as wolf howls echo in a few more canyons than before, this population is still vulnerable and needs more stringent protections and more effective releases from captivity into the wild.”
Environmental groups have pushed for the renewed release of bonded, adult wolves from captivity to help form more packs in unoccupied territory. The bonded pairs in the past have enjoyed a higher survival rate.
The U.S. Fish and Wildlife Service has instead focused on the foster pup releases to bolster and diversify the population. Evidence suggests that captive-reared adult wolves have a harder time learning to hunt game and are more likely to prey on cattle and less likely to avoid humans.
Since 2016, USFWS has released 50 captive-born pups, but just 11 are now known to be alive. Three of the pups have matured and raised young of their own.
The 186 Mexican gray wolves alive today are all descended from two of the last seven wolves in the world before 1980. Of the seven wolves placed in a captive breeding program. One was caught in Arizona in 1959, and the other six were captured in two different batches in Mexico. The lack of genetic diversity has posed a major challenge for the reintroduction program.