Diets of Free-Ranging Mexican Gray Wolves in Arizona and New Mexico

Abstract

Systematic diet studies of Mexican gray wolves (Canis lupus baileyi) were not conducted before wolves were extirpated by the late 1960s from the southwestern United States. We collected carnivore scats (n = 1,682) from the Apache and Gila national forests in Arizona and New Mexico, USA, from April 1998 through October 2001 and identified scats to species using traditional field methods, of which 251 were identified as Mexican wolf scats. We found the diet consisted of large‐sized food items (92.8% percent frequency of occurrence [PFO]), primarily elk (Cervus elaphus) adults (36.6% PFO) and calves (36.2% PFO). Biomass calculations indicated that Mexican wolves consumed 414 kg of prey as represented by the scats, with elk representing 76.7% of the biomass. When comparing PFO with percent biomass, PFO calculations may have underrepresented larger food items and percent biomass may have overrepresented smaller food items. We compared the diet composition of Mexican wolf scats (n = 251) to the diets reported in previous North American gray wolf (C. lupus) studies (n = 7). The high proportion of elk in Mexican wolf diets in our study area may reflect the low‐density, early colonizing stage of the wolf population and elk probably being the most numerous ungulate in our study area. Our results suggested that free‐ranging Mexican wolves consumed a higher proportion of large‐sized prey than other North American gray wolves. Our results provide baseline diet information for a newly reestablished wolf population.

An Account of the Taxonomy of North American Wolves From Morphological and Genetic Analyses

“…North American Fauna I www.fwspubs.org predominant prey is elk (Reed et al 2006;Merkle et al 2009), which is consistent with the predominance of large wild ungulates in the diet of other gray wolves of western North America. C. 1. bailei and C. rufus do not overlap in morphometric variation of skull features (Nowak 1979).…”

Post-parturition habitat selection by elk calves and adult female elk in New Mexico

“…Long‐term (1987–2013, Beaverhead, NM, approx. 30 km east of study area) mean annual precipitation was approximately 35 cm (± 10 cm [SD]; Western Regional Climate Center [WRCC] ); average annual snowfall was 139.3 cm (Reed et al ). Total precipitation during 2010 and 2011 was 26% and 25% below average.…”

“…Most precipitation fell between mid-July and September in thunderstorms and between December and March at higher elevations as snow (USFWS 1996). Long-term (1987-2013 km east of study area) mean annual precipitation was approximately 35 cm (AE 10 cm [SD]; Western Regional Climate Center [WRCC] 2014a); average annual snowfall was 139.3 cm (Reed et al 2006). Total precipitation during 2010 and 2011 was 26% and 25% below average.…”

“…also present. The understory consisted of sparse shrubs and forbs, with a variety of grasses common in more open stands (USFWS 1996, Reed et al 2006, Carrera et al 2008.…”

Relative Impacts of Habitat and Geography on Raccoon Diets

“…Each sample was weighed and then soaked in a water/detergent/alcohol solution for at least 24 h (McFadden et al, 2006). Samples were sieved with a USA number 18 standard sieve (1 mm mesh opening), washed, and again dried to constant mass (McFadden et al, 2006;Reed et al, 2006). Food items were separated by use of forceps with the aid of a head loupe at 33 magnification or a dissecting microscope.…”