Biological Effects :: Aerial Gunning Harms Wildlife

U.S. Department of Agriculture researchers write, “in the Intermountain West, preventive aerial hunting to protect livestock on summer pastures usually occurs from January through March” (Wagner and Conover, 1999). According to documents written by the USDA in Colorado, aerial gunning operations are heavily concentrated in only a handful of counties (USDA 2005). Thus, aerial gunning stresses certain wildlife populations over and again.

A synthesis article by Christopher Pepper et al. (2003) on aircraft overflights suggests that noise pollution can stress animals and people, or damage hearing. Moreover, helicopters (frequently used in aerial gunning operations) create “severe low-frequency sound and vibration” (Ibid.). Noise levels depend on several factors including physical barriers, distance, wind, humidity and temperature (Ibid.).

Studies on wildlife affected by aircraft overflights show changes in cardiac response, body temperature changes, flushing responses, and bird-aircraft collisions. While some animals may habituate to noise — especially if it is not novel — others do not (Ibid.). Many animals must rely on sound to find food, to avoid predators, to reproduce, or find offspring (Ibid.).

Studies have shown that some animals flee when frightened — especially ungulates that have no cover for hiding such as caribou. The heart rate of mountain sheep and desert mule deer have increased, and as a result, a flight response is common and can require “the animal to expend large amounts of energy to escape the perceived threat” (Ibid.). Pepper et al. add, “if there is a short food supply, or if the animal is being stressed in other areas, then there is a possibility for overflights to cause severe negative impacts on some species” (Ibid.).

An earlier synthesis article came to similar conclusions. Low-level flights over wild animals may cause physiological and/or behavioral responses that reduce the animals’ fitness, ability to survive, or ability to reproduce (U.S. Department of Interior/National Park Service, 1995). It is believed that low-altitude overflights can cause excessive arousal and alertness, or stress (Ibid.). Chronic stress can compromise the general health of animals by interfering with raising young, habitat use, and physiological energy budgets (Ibid.).

Bibliography:

Pepper, C., M. Nascarella, and R. Kendall. 2003. A Review of the Effects of Aircraft noise on wildlife and humans, current control mechanisms, and the need for further study. 32 Environmental Management: 418-432.

US Department of the Interior/National Park Service. 1995. Report on the Effects of Aircraft Overflights on the National Park System: Executive Summary Report to Congress.

U.S. Department of Agriculture, Wildlife Services. 2005. Final Environmental Assessment: Predator Damage Management in Colorado.

Wagner, K. and M. Conover. 1999. Effect of preventive coyote hunting on sheep losses to coyote predation. 63 Journal of Wildlife Management: 606-612.