U.S. Department of Agriculture: Animal and Plant Health Inspection Service
United States Department of Agriculture Wildlife Services: Staff Publications
Document Type
Article
Date of this Version
January 2004
Abstract
Black Vulture: The available evidence suggests that black vultures act as typical predators by seeking and disabling vulnerable animals prior to overwhelming and killing them (Gluesing et al., 1980). These birds take the path of least resistance and eat carrion when it is available. Black vultures are opportunists, however, and when the chance arises, they will attack and eat defenseless live animals. Defenseless does not necessarily mean sick or injured. Healthy newborn livestock are defenseless, especially if the mother is exhausted or otherwise not able to care for and protect the offspring. In assessing the role of black vultures as livestock predators, it is difficult to obtain objective, unbiased information because direct observations of black vulture attacks on livestock are uncommon. Usually, the investigator arrives at the feeding site after the prey animal is dead and the chain of events leading to the demise of the animal is speculative. The fact that black vultures are feeding on a carcass is not evidence that the birds killed the animal. Some animals are stillborn and others die for reasons unrelated to black vultures. Female livestock, especially young and inexperienced ones, sometimes suffer mortal injuries while giving birth. If vultures attack and kill such mortally injured animals, they are eliminating individuals that are already doomed. As the black vulture population increases and its range continues to expand, depredations to livestock are likely to increase. To resolve these conflicts, research is needed to understand more fully the population dynamics of this species and to determine factors that contribute to the birds’ preying on livestock. In particular, it will be important to know why some livestock operations incur vulture damage while other ranches are not affected. Research is currently underway specifically to address these data gaps.
Golden Eagle: Golden eagle populations are increasing in western states with sheep production. It is unknown whether increased eagle numbers translates into increases in livestock depredations. It is important for livestock producers to understand that management techniques for golden eagles are limited. The combination of human-like scarecrows, harassment and increased human activity is the most feasible means of protecting lambing bands from golden eagles. As potential new avian management techniques evolve, an effort should be made to evaluate their effectiveness to reduce livestock depredation from golden eagles.
Comments
Published in Sheep & Goat Research Journal 19 (2004), pp. 58-63.