The effects of aircraft noise have been studied more intensively because of their threat to wildlife populations in national and state refuges and parks. Variations in response may be due to temperament, sex, age, and prior experience with noise. Mortality rates were significantly greater in the exposed group. Milk release may have been inhibited in mothers disturbed by the noise leaving calfs 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. 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. Studies are needed to determine the long term effects of noise disturbance.