Noise Effects on Wildlife Factsheet
October 31, 2011
Citizens’ Task Force on Wind Power – Maine
Noise Pollution Clearinghouse
Sources of noise that have the potential to effect wildlife include aircraft overflights, recreational activities such as snowmobiling and motorboating, automobile traffic, and heavy machinery and equipment. The effects of aircraft noise have been studied more intensively because of their threat to wildlife populations in national and state refuges and parks. Impacts to wildlife habitat in remote areas have increased from military aircraft overflights and helicopter activity related to the tourism and resource extraction industries (National Park Service, 1994).
The study of animal response to noise is a function of many variables including characteristics of the noise and duration, life history characteristics of the species, habitat type, season and current activity of the animal, sex and age, previous exposure and whether other physical stressors (e.g. drought) are present (Manci, et al., 1988).
Physiological responses: Disturbances from aircraft noise range from mild, such as an increase in heart rate to more damaging effects on metabolism and hormone balance. Long term exposure to noise can cause excessive stimulation to the nervous system and chronic stress that is harmful to the health of wildlife species and their reproductive fitness (Fletcher, 1980; 1990).
Behavioral responses: Responses vary among species of animals and birds and among individuals of a particular species. Variations in response may be due to temperament, sex, age, and prior experience with noise. Minor responses include head-raising and body-shifting. More disturbed mammals will trot short distances; birds may walk around flapping wings. Panic and escape behavior results from more severe disturbances (National Park Service, 1994).
Behavioral and physiological responses have the potential to cause injury, energy loss (from movement away from noise source), decrease in food intake, habitat avoidance and abandonment, and reproductive losses (National Park Service, 1994). Studies have shown that when certain bird species are flushed from nests in response to noise, eggs are broken and young are exposed to injury and predators (Bunnell et al., 1981; Gladwin, 1987). Young mammals have been trampled as adults attempt to flee from aircraft (Miller and Broughton, 1974). Another study compared mortality rates of caribou calfs exposed to overflights to those not exposed (Harrington and Veitch, 1992). Mortality rates were significantly greater in the exposed group. Milk release may have been inhibited in mothers disturbed by the noise leaving calves malnourished.
Animals rely on hearing to avoid predators, obtain food, and communicate. Auditory systems of some animals are particularly at risk to physical damage from chronic noise, for example desert animals that have evolved an acute sense of hearing. Studies have documented hearing loss caused from motorcycle noise in the desert iguana (Bondello, 1976) and the kangaroo rat, an endangered species (Bondello and Brattstrom, 1979)
Ninety-eight species of birds and mammals on national park lands have been identified as threatened or endangered. The impacts on these species from aircraft noise are largely undocumented. Some of the species became threatened or endangered because of loss of habitat. Further relocation necessary because of noise disturbance might not be possible for these species (National Park Service, 1994).
Studies are needed to determine the long term effects of noise disturbance. Long-term studies have been difficult because of the effort required and the complexity of the variables affecting animal survival (National Park Service, 1994).
Many important studies on wildlife can be found on our website. They include:
- Effects of Aircraft Noise And Sonic Booms on Domestic Animals and Wildlife: A Literature Synthesis (1988). This is a report compiling results of many studies researching noise and its effects on wildlife. The studies focused primarily on mammals and birds, but also includes fish, amphibians reptiles and invertebrates. A brief description of aircraft noise and sonic boom characteristics is also included
- Effects of Aircraft Noise and Sonic Booms on Fish and Wildlife: Results of a Survey of U.S. Fish and Wildlife Service Endangered Species and Ecological Services Field Offices, Refuges, Hatcheries, and Research Centers (1988). This document presents the information provided by biologists and field managers at field installations of National Wildlife Refuges and other similar environments. It documents the effects overflights have on wildlife at the sites and gives recommendations to educate about the problems of overflights and how to deal with them.
- Report to Congress: Report on Effects of Aircraft Overflights on the National Park System (1994). This report details a wide range of costs and benefits of overflights. Included in the report are effects overflights have on natural quiet as a natural resource, cultural and historic resources, wildlife, visitor enjoyment and safety. Values associated with tourist overflights are also taken into account. The report used information from surveys given to park managers and visitors to the park on the ground and in the air. The report gives recommendations to reduce the impact of overflights on National Parks.