Re-introduction of the Mexican Wolf in Arizona and New Mexico, USA

Summary

The Mexican wolf (Canis lupus baileyi), the rarest gray wolf subspecies in North America and extirpated from the wild by the 1980s, has been rebuilt from just seven founders through a binational captive-breeding program from the early 1970s, with reintroduction into an Experimental Population Area in Arizona and New Mexico ongoing since 1998. Restrictive 1998 regulations initially confined where wolves could be released from captivity (2,986 square kilometres) and where they could disperse (18,679 square kilometres), a constraint given the need for continued genetic infusions to offset inbreeding depression documented in both captive and wild wolves; a 2015 revision expanded these areas more than tenfold, to 32,392 and over 398,477 square kilometres. Over 17 years, the US Fish and Wildlife Service and partners refined release techniques from simple captive releases to translocations and, most recently, cross-fostering captive-born pups into wild dens; weekly radio-collar monitoring of at least two wolves per pack tracks locations against depredation reports, with an end-of-2013 minimum count of 83 wolves, all wild-born and some fourth-generation. Persistent local opposition over human safety and livestock impacts, unresolved genetic risk from limited founder diversity, and the absence, until recently, of an updated recovery plan have all complicated the program, along with rising litigation. The project rates itself successful, noting that unlike Rocky Mountain wolf reintroductions using wild-caught founders on largely cattle-free land, this program proved a wild population could be established entirely from captive-released animals on cattle-grazed public land, positioning it to reach its 300-325 wolf target under the expanded 2015 rules.