GAME BIRD RESEARCH

TERLINGUA CREEK CAT’S-EYE
Photo by Ben Masters

Carrion, Scavengers, and the Ecosystem Services Provided By Mountain Lions in the Davis Mountains, Texas

Michael C. Stangl, Patricia Moody Harveson, Louis A. Harveson, and Ryan Luna

Carrion is an essential and underestimated resource in food web ecology, and a comprehensive understanding of its utilization by scavengers, both obligate and facultative, is relatively unknown. Recent studies have illuminated the reverberant effects that carrion, as a resource, and scavenging, as an ecological function, may have on the ecosystem as a whole. In the Davis Mountains, Texas, acts of predation by the lone apex predator, the mountain lion (Puma concolor), and the eradication of invasive nuisance species, such as feral hogs (Sus scrofa), for management purposes, are primary sources of carrion for scavengers.

To further understand carrion, we set motion-triggered cameras at mountain lion kill sites and feral hog carcasses to determine which members of the vertebrate community were actively scavenging on naturally and anthropogenically introduced carrion. We fitted two mountain lions with GPS collars in January 2017, and investigated nine kill sites between January 2017 and December 2018. During this time we also initiated 10 “open” feral hog carcass sites and 10 “closed” feral hog carcass sites. We documented scavengers feeding at all three carcass types for a sum of 45,276.7 min, with a sum presence of 54,034.7 min.

From our data collection, we found that 11 mountain lion kill sites had a greater scavenger species richness than either of the seven open feral hog or five closed feral hog sites. We also found that mountain lion kill sites were significantly more diverse in scavenger species than all feral hog sites. The results of this study support other research that highlights the importance of apex predators, such as mountain lions, in ecosystem functionality via the facilitation of carrion to scavengers. Our research also indicates the dynamic complexities that govern scavenger communities, as is expressed in the inter- and intraspecific relationships of scavenging species.

Funding source: the Summerlee Foundation, Horizon Foundation, Sibley-Potts Foundation, The Nature Conservancy, and private donors.