Two views of the impacts of poaching on bighorn sheep in the upper Yellowstone valley, Montana, USA

• Published in: Biological conservation Vol. 47; no. 4; pp. 259 - 272
• Main Authors: Irby, Lynn R., Swenson, Jon E., Stewart, Shawn T.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1989; Elsevier
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Fundamental and applied biological sciences. Psychology; Ovis canadensis; Montana; Hunting; United States; Population number; North America; Survival; Enumeration(counting); Sex ratio; Vertebrata; Mammalia; America; Population dynamics; Artiodactyla; Ovis canadensis; Ungulata
• ISSN: 0006-3207; 1873-2917
• DOI: 10.1016/0006-3207(89)90069-4

An analysis of data from wildlife law enforcement agencies and field surveys of bighorn sheep populations in the upper Yellowstone River valley of Montana produced two opposing views of the impacts of poaching. Low survivorship of males in older age classes (6–7 years of age and older) and 29 reported illegal kills over a 7-year period versus 35 legal kills suggested that poaching might have serious consequences for legal harvest, game viewing, and possibly genetic quality of herds in the area. Tolerance of sheep to close approaches on winter range and observed population changes (numeric and age/sex ratios) over 8 years suggested that impacts were not serious.