Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (5000-20,000 square km (about 2000-8000 square miles)) Range formerly extended from southern Arizona, southern New Mexico, and western Texas south through much of northern and central Mexico. As of the mid-1990s, none occurred in the U.S. and very few or none remained in Mexico (most likely in eastern Sonora, western Chihuahua, and Zacatecas) (Johnson 1991; USFWS, Federal Register, 1 May 1996). In 1998, reintroductions began within an area (Blue Range Wolf Recovery Area) encompassing a portion of eastern Arizona and western New Mexico. This area is part of a larger "Nonessential Experimental Area" extending across much of Arizona and New Mexico and a small portion of far western Texas. Currently, free-ranging wolves exist in both Arizona and New Mexico (USFWS 2013).
See Hoffmeister (1986) for information on runways or hunting beats that historically were used in southern Arizona.
occurs (regularly, as a native taxon) in multiple nations
Length: 205 cm
Weight: 59000 grams
Catalog Number: USNM 98312
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Male; Adult
Preparation: Skin; Skull
Collector(s): E. Nelson & E. Goldman
Year Collected: 1899
Locality: Colonia Garcia, near, ca 60 mi SW of Casas Grandes, Chihuahua, Mexico, North America
Elevation (m): 2042
- Type: Nelson, E. W. & Goldman, E. A. 1929 May 09. Journal of Mammalogy. 10: 165.
Sierra Madre Occidental Pine-oak Forests Habitat
This taxon is found in the Sierra Madre Occidental pine-oak forests ecoregion, which boasts some of the richest biodiversity anywhere in North America, and contains about two thirds of the standing timber in Mexico. Twenty-three different species of pine and about 200 species of oak reside within the Sierra Madre Occidental pine-oak forests ecoregion.
Pine-oak forests here typically grow on elevations between approximately 1500 and 3300 meters, and occur as isolated habitat islands in northern areas within the Chihuahuan Desert. Soils are typically deep, where the incline allows soil build-up and derived from igneous material, although metamorphic rocks also form part of the soils in the west and northwest portions of the sierra. Steep-sloped mountains have shaped some portions of the Sierra, while others are dominated by their deep valleys, tall canyons and cliffs. These steep-sided cliffs have thinner soils limiting vegetation to chaparral types; characterized by dense clumps of Mexican Manzanita (Arctostaphylos pungens), Quercus potosina and Netleaf Oak (Q. rugosa). There are also zones of natural pasture, with grasses from the genera Arisitida, Panicum, Bromus and Stevis.
The pine-oak forests gradually transform into an oak-grassland vegetative association. Such communities represent an ecological transition between pine-oak forests and desert grasslands.. Here, species such as Chihuahuan Oak (Quercus chihuahuensis), Shin Oak (Q. grisea), Q. striatula and Emory Oak (Q. emoryi), mark a transition zone between temperate and arid environments, growing in a sparse fashion and with a well-developed herbaceous stratum resembling xeric scrub. Cacti are also part of these transition communities extending well into the woodlands. Some cacti species such as the Little Nipple Cactus (Mammillaria heyderi macdougalii), Greenflower Nipple Cactus (M. viridiflora), Mojave Mound Cactus (Echinocereus triglochidiatus), and Leding's Hedgehog Cactus (E. fendleri var. ledingii) are chiefly centered in these biotic communities. The dominant vegetation in the northernmost part of the ecoregion in the Madrean Sky Islands includes Chihuahua Pine (Pinus leiophylla), Mexican Pinyon (P. cembroides), Arizona Pine (P. arizonica), Silverleaf Oak (Quercus hypoleucoides), Arizona White Oak (Q. arizonica), Emory Oak (Q. emoryi), Netleaf Oak (Q. rugosa), Alligator Juniper (Juniperus deppeana), and Mexican Manzanita (Arctostaphylos pungens).
This ecoregion is an important area for bird richness and bird endemism. Likewise, virtually all of the ecoregion is included in the Sierra Madre Occidental and trans-mexican range Endemic Bird Area. Endemic bird species include the Thick-billed Parrot (Rhynchopsitta pachyrhyncha EN) which is in danger of extinction, with population estimates as low as 500 pairs; the Tufted Jay (Cyanocorax dickeyi NT), Eared Quetzal (Euptilptis neoxenus NT) and the Green-striped Brush Finch (Buarremon virenticeps). Temperate and tropical influences converge in this ecoregion, forming a unique and rich complex of flora and fauna. Many other birds are found in this ecoregion including the Green Parakeet (Aratinga holochlora), Eared Trogon (Euptilotis neoxenus NT), Coppery-tailed Trogon (Trogon elegans), Grey-breasted Jay (Aphelocoma ultramarina), Violet-crowned Hummingbird (Amazilia violiceps), Spotted Owl (Strix occidentalis NT), and Golden Eagle (Aguila chryaetos). Some species found only in higher montane areas are the Gould's Wild Turkey (Meleagris gallopavo mexicana), Band-tailed Pigeon (Patagioenas fasciata), Mexican Chickadee (Poecile sclateri) and Hepatic Tanager (Piranga flava).
The Sierra Madre Mantled Ground Squirrel (Spermophilus madrensis NT) is an endemic to the Sierra Madre Occidental pine-oak forests, restricted to southwestern Chihuahua, Mexico. The Mexican Gray Wolf (Canis lupus baileyi) and Mexican Grizzly Bear (Ursus horribilis), although considered by most to be extinct from this ecoregion, once roamed these mountains. Mammals also present include White-tailed Deer (Odocoileus virginianus), American Black Bear (Ursus americanus), Buller’s Chipmunk (Tamias bulleri), endemic Zacatecan Deer Mouse (Peromyscus difficilis), rock Squirrel (Spernophilis variegatus), Zacatecas Harvest Mouse (Reithrodontomys zacatecae) and Coati (Nasua nasua), to set forth a subset of mammals present.
Reptiles are also numerous in this ecoregion. Fox´s Mountain Meadow Snake (Adelophis foxi) is an endemic taxon to the ecoregion, only observed at the type locality at four kilometers east of Mil Diez, about 3.2 kilometers west of El Salto, in southwestern Durango, Mexico. There are at least six species of rattlesnakes including the Mexican Dusky Rattlesnake (Crotalis triseriatus), Mojave Rattlesnake (C. scutulatus), Rock Rattlesnake (C. lepidus), Western Diamondback Rattlesnake (C. atrox), Twin-spotted Rattlesnake (C. pricei), and Ridgenose Rattlesnakes (C. willardi). Clark's Spiny Lizard (Sceloporus clarkii) and Yarrow's Spiny Lizard (S. jarrovii), Bunchgrass Lizard (S. scalaris), and Striped Plateau Lizard (S. virgatus) are several of the lizards found in the Sierra Madre Occidental pine-oak forests.
Along springs and streams the Western Barking Frog (Craugastor augusti) and the Tarahumara Frog (Rana tamahumarae) are two anuran taxa occurring in the ecoregion. Other anuran taxa found here include: Bigfoot Leopard Frog (Lithobates megapoda), Northwest Mexico Leopard Frog (Lithobates magnaocularis) and the Blunt-toed Chirping Frog (Eleutherodactylus modestus VU). The Sacramento Mountains Salamander (Aneides hardii) is an endemic salamander found in the Sierra Madre Occidental pine-oak forests, restricted to the Sacramento Mountains, Capitan Mountains, and Sierra Blanca in Lincoln and Otero Counties within southern New Mexico, USA.
- World Wildlife Fund & C. Michael Hogan. 2013."Sierra Madre Occidental pine-oak forests". Encyclopedia of Earth, National Council for Science and the Environment, Washington DC ed. Rodney L. Honeycutt.
- David E. Brown, ed. 1994. Biotic Communities: Southwestern United States and Northwestern Mexico. University of Utah Press, Salt Lake City, Utah. ISBN: 0874804590
Comments: These wolves are not limited to any particular habitat type, but viable populations occur only where human population density and persecution level are low and prey densities are high. Young are born in a den that may be on a bluff or slope among rocks or in an enlarged badger hole (Hoffmeister 1986).
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
These wolves probably are similar to other subspecies as follows: annual home range up to several hundred square kilometers; may occasionally move several hundred kilometers, especially dispersing young. Historical information indicates that a hunting runway of 70 miles would be traversed about every nine days (see Young and Goldman 1944, Hoffmeister 1986).
Comments: Ungulates are the predominant prey. When ungulate populations are low or seasonally unavailable, wolves may eat alternative prey such as lagomorphs, rodents, and carrion. Reintroduced wolves in Arizona and New Mexico subsist primarily on elk and sometimes take livestock, deer, rodents, or lagomorphs (Merkle et al. 2009). Runways or hunting beats follow stream beds, washes, old game trails, and old roads and mostly occur in open country (Young and Goldman 1944).
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 1 - 5
Comments: This subspecies is represented by only one extant occurrence in Arizona-New Mexico (USFWS 2013). It is unlikely that a viable population exists in Mexico.
50 - 250 individuals
Comments: At least 75 Mexican wolves existed in the wild in Arizona and New Mexico at the end of 2012 (compared to the 2011 minimum population count of 58 wolves) (USFWS 2013). All but one of the 75 wolves were born in the wild (versus captive born). The 2012 minimum population count included at least 20 wild-born pups that survived through the end of the year (USFWS 2013). The number of wolves in Mexico is unknown but likely quite small.
These wolves probably are similar to other subspecies as follows: packs consist of one or more family groups with dominance hierarchy; population density low; generally not instrumental in causing prey declines, the effect varying with other circumstances.
Life History and Behavior
Comments: Mainly nocturnal
Gestation lasts about 2 months. Young are born in March and early April (Hoffmeister 1986). Litter size may average around 6-7; one litter/year. Only the dominate male/female mate and rear offspring. Young are tended by both parents. Young and parents leave den when young are about 3 months old. Pups are weaned probably in about 5-7 weeks. Some offspring remain with pack, others disperse as they mature. Breeding first occurs during the second or third year (Hoffmeister 1986).
National NatureServe Conservation Status
Rounded National Status Rank: N1 - Critically Imperiled
NatureServe Conservation Status
Rounded Global Status Rank: T1 - Critically Imperiled
Reasons: Historically widespread in the southwestern United States and adjacent Mexico; extirpated from all or nearly all of historical range, mainly as a result of trapping and poisoning, plus some habitat loss from human encroachment; reintroduced into a recovery area in Arizona and adjacent New Mexico; as of early 2013, the wild population was increasing and included at least 75 individuals, all but one of which were born in the wild.
Global Short Term Trend: Relatively stable to increase of 25%
Comments: Reintroduced population in Arizona-New Mexico has been increasing in recent years (USFWS 2013).
Global Long Term Trend: Decline of >90%
Comments: Distribution and abundance have decreased greatly over the long term.
Degree of Threat: Low
Comments: Historically this subspecies was widespread, then it was exterminated from essentially all of the range through trapping, poisoning, shooting, and reduction of prey resources. Habitat within the historical range has greatly decreased as a result of human encroachment. In the reintroduced population in Arizona-New Mexico, up to several individuals die each year as a result of illegal shooting, and 0-2 are killed each year by collisions with vehicles (USFWS 2013).
Needs: USFWS Recovery Program covers most needs. Protect large areas with potential habitat. Promote reintroduction effort. The goal of the Mexican wolf recovery plan is to establish a viable, self-sustaining population of at least 100 individuals in the middle to high elevations of a 5000-square-mile area somewhere within the historic range (Johnson 1991).
Relevance to Humans and Ecosystems
Stewardship Overview: Ongoing major management includes propagation in captivity, releases of captive-bred wolves to improve the genetic makeup of the wild population, habitat management to increase the capacity of the area to support more wolves, actions to decrease wolf-livestock interactions, and compensation to livestock producers to offset the costs of wolf depredations (USFWS 2013).
The U.S. Fish and Wildlife Service Southwest Region has initiated the revision of the 1982 Mexican Wolf Recovery Plan. In December 2010, the Southwest Regional Director appointed a new recovery team to develop a revised recovery plan for the Mexican wolf. The Mexican Wolf Recovery Team includes a Tribal Liaisons Subgroup, Stakeholder Liaisons Subgroup, Agency Liaisons Subgroup, and a Science and Planning Subgroup. When completed and approved by the Southwest Regional Director, the Revised Mexican Wolf Recovery Plan will include objective and measurable recovery criteria for removing the Mexican wolf from the List of Threatened and Endangered Wildlife and Plants, management actions that will achieve the criteria, and time and cost estimates for these actions. USFWS will begin exploring options for implementation of the Revised Mexican Wolf Recovery Plan's recovery actions in 2013 and beyond. Source: USFWS (2013).
The Blue Range Mexican Wolf reintroduction project is managed by the U.S. Fish and Wildlife Service in collaboration with the following cooperating agencies: Arizona Game and Fish Department, USDA Forest Service, USDA-APHIS Wildlife Services, and the White Mountain Apache Tribe. These agencies, along with the Arizona counties of Graham, Greenlee, and Navajo, work together under a formal memorandum of understanding that provides a framework for collaboration (USFWS 2013).
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