Eagle-Livestock Relationships: Livestock Carcass Census and Wound Characteristics

Abstract

This paper reviews the physical damage eagles inflict when attacking their prey and, with these and other descriptions of wounds as guides, reports a field appraisal of livestock succumbing to predation on western rangelands. Massive subcutaneous hemorrhages and talon punctures on the dorsal surface of lambs characterize a victim of an eagle attack. Head and facial wounds are seldom present on eagle kills. More livestock carcasses were located per manhour of search in the Edwards Plateau Region (represented by the Eldorado, Texas, area) than elsewhere. How- ever, using criteria we developed from the literature and from our own observations, we believe that no more than 10 percent of these carcasses were actually victims of predation (all types). Still births and other circumstances seemed to account for many of the other losses. Our studies in the Edwards Plateau Region did not fully coincide with the beginning of the region's lambing season. About 38 percent (3) of the dead lambs and kids found in the Val Verde Region of Texas were attributed to predatory losses. Only two dead lambs were discovered in the Guadalupe Mountain Region in 148 manhours of search; of these, one appeared the victim of predation, the other was a birth fatality. Overall, 25 percent of the deaths we could analyze among lambs and kids were attributable to predators. Ranchers we interviewed indicated that little or no eagle damage occurred during the course of our field work, a contention we fully support. Claims of livestock losses from predation have fostered both exten- sive and intensive predator control measures on many western range- lands. Stockmen and conservationists nonetheless often differ in their views of these controls and their ecological impact. Hence Leopold et al. (1964) prepared a comprehensive review of the philosophies and practices associated with predator control as a guideline for agencies charged with the stewardship and management of wildlife popula- tions. This policy statement, in particular, urged that specific predators be identified and that any susbequent control measures be both selec- tive and locally applied.