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AZ: Wild Mexican wolf numbers surged in 2019

by Peter Aleshire, Consulting publications editor

The number of Mexican wolves in the wild jumped 24% to 163 in 2019, the biggest increase in years.

The number of wolves in the wild has grown sharply in the last two years, despite a steady stream of wolf killings — especially in New Mexico.

The expensive effort to reintroduce the wolves has struggled for 20 years, plagued by low survival rates by the pups, genetic inbreeding, conflicts with ranchers, frequent killings of wolves by humans and other problems. The first 11 captive-reared wolves were released in 1998.

Shortly after announcing the big population increase in 2019, federal wildlife managers killed four wolves who had been preying on cattle. Then in late March, someone killed two wolves near Pinetop in the White Mountains. The USFWS has offered a $37,000 reward for information leading to the arrest of whoever killed the wolves, whose bodies were found on March 22 and March 23 near Porter Mountain Road.

The USFWS has faced a series of lawsuits supported by biologists and environmental groups who say the federal government should enlarge the active management area and speed up the introduction into the wild of wolves born in captivity. The USFWS considers the wild wolf population an “experimental” and “non-essential” population, which gives the government more flexibility on killing or removing wolves that conflict with cattle or humans inside the overall recovery area — which includes much of Arizona and New Mexico south of I-40.

Currently, the USFWS has divided the recovery area into three zones. The wolves are managed in Zone 1, mostly in the White Mountains and New Mexico’s Canton County. The USFWS doesn’t introduce wolves outside that small area and can remove or kill wolves that prey on cattle, pets or humans.

If wolves make it out of the recovery area altogether, they’re no longer part of the experimental population and as an endangered species it becomes illegal to kill or harass them.

Ranchers argue the wolves prey on their cattle and may drive them out of business.

Biologists and environmentalists argue the species will only survive if the USFWS expands the active management area and steps up captive releases.

The recently completed census offers support for both camps, with a big population jump, continued wolf-killings, frequent incidents involving livestock and continued success of a program that puts captive-born pups into wild wolf dens.

The Mexican wolf is a subspecies of the gray wolf, whose numbers are increasing in select areas in the West. In some states, the gray wolves have been taken off the endangered species list.

The Mexican wolf count relied on ground-sightings in November, December and January and helicopter flights in February to locate and count the wolf packs. About half of the wolves are wearing functional radio collars, which help in the census operation.

The 163 wolves included 76 in Arizona and 87 in New Mexico. The wolf population has increased at a rate of about 10% annually for the past 10 years, despite heavy losses.

The census found at least 42 wolf packs at the end of 2019, including 11 new pairs who had set up housekeeping during the year. Of the 28 packs of breeding age with radio collars, 21 produced pups and 19 had pups that survived to the end of the year. Some 58% of the 90 pups survived their first year.

The census documented 14 mortalities in the wolf population in 2019, which sounds bad, but it’s a 33% decrease from the 21 recorded in 2018. Humans caused the great majority of confirmed mortalities.

Biologists continued to cross-foster wolf pups, slipping captive-born pups into the dens of wild mothers with pups of almost exactly the same age. The wolves usually changed dens after they were disturbed, but then adopted the new pups.

Last year, biologists placed 12 captive born pups into five wild dens, hoping to increase the genetic diversity of the wild-born wolves. At least two of those 12 foster pups have survived.

Overall, at least four foster pups have survived long enough to have pups of their own. Three more will reach breeding age this year.

“The numbers highlight the wolf’s progress in the wild,” said Jim deVos, assistant director of wildlife management for the Arizona Game and Fish Department. “The results of this census are very important as they reflect the great progress being made in the recovery of the Mexican wolf in the United States. The increase in the Mexican wolf population is not an isolated year, but rather a continuum of increases over the last 10 years.”

The Centers for Biological Diversity hailed the population growth of the wolves, but renewed its call for the U.S. Fish and Wildlife Service to again begin releasing from captivity family groups, including a male, a female and their young. The group also joined in the lawsuit that overturned the 2017 plan.

“This increase represents countless moments of wolf vigilance and smarts in avoiding people, which is a big part of keeping their precious pups alive, said Michael Robinson with the Centers for Biological Diversity. “It is heartening to have more wolves in our forests, but federal officials need to take much stronger action to establish healthy genetic diversity.”

He noted that of 30 captive born pups released between 2016 and 2019, seven are known to have survived.

Ranchers have generally opposed to release of family groups, reasoning that the captive-reared adults won’t have the hunting skills needed to bring down deer and elk. As a result, they might prove more likely to prey on cattle.

Moreover, the program grew slowly in the early years due to the struggles of the original, captive-born wolves to adjust to the wild. They suffered higher mortality rates and lower rates of reproduction than wild-reared wolves.