Release of Three Mexican Gray Wolf Packs Needed to Put Recovery Back on Track

Twenty-five conservation groups called on the U.S. Fish and Wildlife Service today to release three more Mexican gray wolf packs, specifically mating pairs with pups, to the Gila Wilderness in New Mexico this summer.

Further releases are badly needed to improve numbers and enhance genetic diversity of the endangered canines to give the species a chance at survival.

Release of packs was used to get reintroduction off the ground in 1998. But in 2007 the Service halted almost all releases of captive-born wolves due to pressure from the livestock industry seeking to limit expansion of the wolves’ numbers and range. Then in 2016 the Service switched to “cross-fostering,” the release of captive-born pups into existing packs in the wild and without their parents.

Only two among 10 cross-fostered pups in 2016 and 2017 are known to survive, suggesting the approach is not working.

“Mexican gray wolves are in a race with extinction, and the clock is ticking,” said Bryan Bird, Defenders of Wildlife's Southwest program director. “If we’re committed to saving this animal from extinction then the Fish and Wildlife Service needs to release more adult wolves into the wild and improve their genetic condition.”

Wolf releases are necessary because, beginning in 2003, government trapping and shooting of wolves and infrequent releases from captivity reduced diversity and led to genetic homogeneity. Now almost every wolf in the population is related to every other wolf as if they were siblings. The close relatedness has been correlated with fewer pups born per litter. Between 2014 and 2017, the population grew by just four, from 110 to 114 animals.

“For years, conservationists and scientists alike have been telling Fish and Wildlife, we need more wolves in the wild, sooner, in order to bolster genetic diversity and ultimately to help endangered Mexican wolves have a better chance at recovery,” said Sandy Bahr with Sierra Club’s Grand Canyon (Arizona) Chapter. “We cannot afford to wait, the wolves cannot afford to wait.”

“The states and special interests have been opposing adult and family releases, and the Service has been going along with their agenda,” said Greta Anderson, deputy director of Western Watersheds Project. “It’s time for the Service to start following the Endangered Species Act’s recovery mandates instead, and to do what it takes to improve the genetic health of the wild population.”

Cross-fostering of newborn Mexican wolves from captivity to the wild began in 2016 with six pups, followed by four in 2017 and eight this spring. Only one pup from 2016 and one from 2017 were known to have survived to the end of each year, amounting to a two-year average 80 percent disappearance or mortality rate. That’s almost triple the 28 percent pup-mortality rate the Service predicted last year in its Mexican Wolf Recovery Plan. Even if a few more of the 2016 and 2017 pups are subsequently determined to have survived, the pup-mortality rate would still prove excessive.

Beyond high mortality rates in cross-fostering, logistical limitations on bringing captive-born pups from out-of-state to roadless den sites have led to curtailed releases. Between 2016 and this year, the Service intended to release 12 pups each spring, which would have equaled 36 pups released. But just 18 were actually released.

“The heartbreaking loss of so many cross-fostered pups means the Service must return to the more reliable technique of releasing wolf families together,” said Michael Robinson, a conservation advocate at the Center for Biological Diversity. “In most cases there’s no good reason these pups’ parents shouldn’t be released with them.”

“If this were a genuine recovery effort, we would see mating adult pairs with pups being placed in the wild,” said Christopher Smith, Southern Rockies wildlife advocate at WildEarth Guardians. “Unfortunately, it’s not. It’s a process being driven by a small minority of interests rather than science, and it is failing to recover lobos.”

Meanwhile, according to just-published research, the southwestern wolf population’s genetic plight is worsening, even as its numbers stall. The well-managed captive population retains significantly more genetic diversity than the U.S. wild population, but its gene pool is shrinking also because of insufficient pen space in the 55 captive-breeding institutions to house more than 300 wolves, which is not enough to maximize retention of genetic diversity.

“We have a responsibility to fix what we broke all those years ago,” said Hailey Hawkins of the Endangered Species Coalition. “The U.S. Fish and Wildlife Service should do everything possible to save the Mexican wolf from genetic distress and extinction — not just for the wolves’ sake, but for the sake of our children and our natural heritage.”