Chop-Chop -- The Impacts of Helicopter Recreation on Wildlife
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Remember the days of sweating and climbing up steep slopes to gain spectacular views and relish the sounds of silence? Silence is not so easily won these days, even in remote wilderness.With the aging and relatively affluent baby-boomer market, helicopter recreation is one of the fastest growing types of wilderness adventure. Heliskiing, heli-hiking, heli-site seeing, and heli-fishing are all forms of helicopter recreation and along with the increase in human activity in wilderness, they raise concerns about impacts to wildlife populations.
A Varied Response
Helicopter disturbance of wild animals may cause physiological and/or behavioral responses that compromise the animalsø survival, growth and reproductive fitness, ability to raise young, energy budgets, and habitat use. Behavioral responses in animals vary among individuals within a species and between species types; these variations may be due to differences in emperament, sex, age, prior experience with aircraft, or other factors (McKechnie and Gladwin 1994). One relationship is clear between aircraft and behavioral responses: the closer the aircraft the greater the probability that the animal will respond, and the greater the response.
Accidents Happen
Accidental injury of animals that panic and run from aircraft is a common concern of biologists. Occasionally animals, especially young ungulates, will run into objects or fall and get trampled while fleeing from aircraft.
Reproductive Stress
Aircraft disturbances can cause reproductive losses by altering patterns of attendance to young (National Park Service 1994). Both mammals and birds leave their young or eggs exposed to predators and the elements when they run or fly away from aircraft.
Energy Loss
Panic reactions and escape responses to overflights can be energetically îexpensive" to animals for two reasons. First, feeding animals nearly always stop ingesting food when disturbed, which means a decrease in energy intake. Second, disturbed animals usually run or otherwise move away from aircraft, thus increasing their energy expenditure (National Park Service 1994). Increased energy expenditures can reduce the rate of survival and reproduction (Albright and Kunstel 2001). Disturbance from overflights could cause sensitive animals to abandon their habitats. However, more research is needed on the long-term effects of helicopter isturbances.
Associated Impacts
Helicopter recreation raises concern not only about the impact of helicopters themselves but also about associated increases in recreation. Heli-skiing is concentrated in upper-elevation terrain, where goats, caribou, elk, and brown bears occupy habitat. In 1997, a human-triggered avalanche in the Chugach Mountains of Alaska killed a female Brown Bear and her two cubs while hibernating. Likewise, the increase in heli-hiking is taking more people to historically lowuse areas like high alpine or tundra. Alpine habitat is extremely fragile and cannot support such use at high levels; by bringing in groups by helicopter, the numbers and degree of disturbance will increase. Trampled alpine vegetation causes increased stress on wildlife - mountain goats and sheep are particularly vulnerable to this type of disturbance because critical habitat is already in short supply. There are also concerns related to two aspects of brown bear/helicopter/recreational conflicts (ADF&G 1992). First, most individual bears flee approaching helicopters in a full run. If helicopter activity were frequent, bears would most likely move away from a locale (ADF&G 1992). The second concern is for the direct human intrusion into brown bear habitats. Hiking in alpine terrain increases the risk of grizzly/human conflicts. Such conflicts will result in more grizzlies being destroyed in the name of public safety.
Case Studies
Because helicopter recreation is relatively new, review of the literature found few studies that specifically examine the effects of helicopter recreation on wildlife. However, many studies have examined the responses of wildlife to mechanized recreational activities and human disturbances. Therefore, the majority of studies lend themselves to drawing conclusions about the impacts of helicopter recreation.
Perching or nesting birds may flush when disturbed. A study of bald eagles elicited responses from over 40% of eagles when helicopters approached at distances of under 3,050m (Watson 1993). In Alaskaøs Arctic National Wildlife Refuge, heli flights have caused flight/fright behavior in tundra swans and snow geese, and swans have abandoned nests due to the disturbance (Albright and Kunstel 2001). Presence of young in the nest increased tenacity. Eagles, presumably defending their young, did not flush until encounters under 30m (Watson 1993). What seems to be no disturbance and a lack of response to human activities may actually be a form of nest defense (Watson 1993). Even if adults do not flush, regular disruption of nesting activities by aircraft or other human activities (i.e. hiking, skiing, etc.) could result in reduced brooding and feeding of young. This may lead to reduced attentiveness and nest failure (Watson 1993).
A rather significant study in 1982 by Ann Gunn looked at Caribou behavior, range use patterns, and short-term responses to helicopter landings on the Beverly Calving Ground. The study included an experimental disturbance with eight phases: approach, turn, descent, wind-down, shutdown and ground activity, wind-up, take-off, and last audible (Gunn 1982). Gunn found that there were relatively more occasions than expected when caribou exhibited maintenance behaviors or behavioral responses to the helicopter (Gunn 1982). For example, Caribou responded to the helicopter by galloping and trotting during the turn phase. The results from the experimental landings showed that the cows and calves were readily displaced and their activity patterns interrupted even by landing at a distance of 300-2200m away from them. Overall, the study found that helicopter landings within several hundred meters of early post-calving groups or aggregations of caribou will 1) disrupt ongoing maintenance activities; and 2) elicit behavioral responses that lead to displacements from the immediate range to distances of, at least, 1-3km.
A study in 1987 by biologists from Northern Arizona University investigated whether helicopter activities in Grand Canyon National Park affected the feeding behavior of bighorn sheep (Stockwell and Bateman 1991). They found that in the presence of helicopters, sheep were taking in less energy and expending more. Specifically, sheep spent 14% less time feeding during the spring and 42% less in the winter. Meanwhile, the sheep walked 50% more while feeding (McKechnie and Gladwin 1994).
Conclusion & Recommendations
There is a general consensus in the literature that helicopter traffic is more disruptive than fixed-wing overflights (Watson 1993, Albright and Kunstel 2001, Harrington and Veitch 1991, Belanger and Bedard 1989). The literature indicates that flight altitude, noise output, speed, and approach pattern are the most important factors in determining an animaløs reaction to an overflight (McKechnie and Gladwin 1994). Review of current literature and information suggests the following regulations to mitigate impacts of helicopter recreation:
--- Emily Yeomans is a graduate student in Environmental Studies at the Univ. of Montana and a longtime outdoor educator who has seen the effects of helicopter recreation first hand.
References
Albright, J. and M. Kunstel. 2001. A Research Report for the Jackson Hole Conservation Alliance. Jackson, WY.
Anderson, D. E., O.J. Rongstad, W.R. Mytton. 1990. Home-range changes in raptors exposed to increased human activity levels in southeastern Colorado. Wildlife Society Bulletin 18(2):134-142.
Belanger, L. and J. Bedard. 1989. Responses of staging greater snow geese to human Disturbance. Journal of Wildlife Management 53(3):713-719.
Bunnell, F.L., D. Dunbar, L. Koza, and G. Ryder. 1981. Effects of disturbance on the productivity and numbers of white pelicans in British Columbia¤observations and models. Colonial Waterbirds 4:2-11.
Callanan, L. 1993. Heli-hiking in the bugaboos. Forbes 151:166-170.
Cassirer, E. F., D.J. Freddy, and E.D. Ables. 1992. Elk Responses to disturbance by cross-country skiers in Yellowstone National Park. Wildlife Society Bulletin 20:375-381.
Delaney, D.K., T.G. Grubb, P. Beier, L.L. Pater, and M.H. Reiser. 1999.
Effects of helicopter noise on Mexican Spotted Owls. Journal of Wildlife Management 63:60-76.
Ferguson, M.A.D., and L.B. Keith. 1982. Influence of Nordic skiing on distribution of Moose and Elk in Elk Island National Park, Alberta. Canadian Field-Naturalist 96(1):69-78.
Gladwin, D.N., D.A. Asherin, and K.M. Manci. 1987. 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. NERC-88/30. U.S. Fish and Wildl. Serv., National Ecology Research Center, Fort Collins, CO. 24pp.
Gunn, A. 1983. Caribou Behavior, Range Use Patterns, and Short-Term Responses to Helicopter Landings on the Beverly Calving Ground, N.W.T. Yellowknife Wildlife Service, Northwest Territories, Renewable Resources.
Harrington, F.H. and A.M. Veitch. 1991. Short-term impacts of low-level jet fighter training on Caribou in Labrador. Arctic 44(4):318-327.
Hilderbrand, G.V., L.L. Lewis, J. Larrivee, and S.D. Farley. 2000. A denning brown bear, Ursus arctos, sow and two cubs killed in an avalanche on the Kenai Peninsula, Alaska. Canadian Field-Naturalist 114(3):498.
Johnson, B. 1977. The effects of human disturbance on a population of harbor seals. In Environmental Assessment of the Alaskan Continental Shelf, 422-431. Annual Reports of Principal Investigators for the Year Ending March 1977, Vol. 1, Receptors-Mammals.
Jope, K. L. 1985. Implications of grizzly bear habituation to hikers. Wildlife Society Bulletin 13:32-37.
Knight, R.L., and K.J. Gutzwiller. 1995. Wildlife and Recreationists: Coexistence through Management and Research. pp. 51-156. Island Press.
Krausman, P.R., B.D. Leopold, and D.L. Scarbrough. 1986. Desert mule deer response to aircraft. Wildlife Society Bulletin 14:68-70.
Little, J.B. 1999. Quiet! The sounds of nature are harder to hear. Wilderness 21-25.
MacArthur, R.A., V. Geist, and R.H. Johnston. 1982. Cardiac and behavioral responses of mountain sheep to human disturbance. Journal of Wildlife Management 46:351-358.
Maffly, Brian. 2000. Forest Service Upholds Copter-Ski Ruling. Salt Lake Tribune, Jan. 6th, 2000.
Maffly, Brian. 2000. Compromise on Heli-Skiing Pleases Nobody. Salt Lake Tribune, Jan. 3rd, 1999.
McKechnie, A. and D. Gladwin. 1994. Helicopters and Wildlife. Rotor and Wing 32-33. Miller, F.L., E. Broughton, and A. Gunn. 1988. Mortality of Migratory Barren-Ground Caribou on the Calving Grounds of the Beverly Herd, Northwest Territories, 1981-83. Ottawa: Canadian Wildlife Service Occasional Paper No. 66.
National Park Service. 1994. Report to Congress: Report on Effects of Aircraft Overflights on the National Park System. Denver Service Center.
Phillips, G.E. and A. W. Alldredge. 2000. Reproductive success of elk following disturbance by humans during calving season. Journal of Wildlife Management 64(2):521-530.
Stockwell, C.A., G.C. Bateman, and J. Berger. 1991. Conflicts in national parks: a case study of helicopters and bighorn sheep time budgets at the Grand Canyon. Biological Conservation 56:317-328.
Thiel, R.P., S. Merrill, and L.D. Mech. 1998. Tolerance by Denning Wolves, Canis lupus, to Human Disturbance. Canadian Field-Naturalist 112(2):340-342.
Titus, K. 1992. Letter to the USDA Forest Service. Alaska Department of Fish and Game. Douglas, AK.
U.S. Department of Agriculture. 1999. Final environmental impact statement for the Wasatch Powderbird Guides permit renewal. Wasatch-Cache National Forest, Salt Lake City, UT and Unita National Forest, Provo, UT. pp.3-35-3-40.
U.S. Department of Agriculture. 1997. Helicopter Landings in Wilderness: Final Environmental Impact Statement. Alaska Region, Tongass National Forest. Chatham, Stikine, and Ketchikan Areas. RM-MB-340a.
Watson, J.W. 1993. Responses of nesting bald eagles to helicopter surveys. Wildlife Society Bulletin 21:171-178.
Wilson, S.F. and D.M. Shakleton. 2001. Backcountry Recreation and Mountain Goats: A Proposed Research and Adaptive Management Plan. Wildlife Research Group, University of British Columbia, Vancouver, BC.
Yarmoloy, C., M. Bayer, and V. Geist. 1988. Behavior responses and reproduction of mule deer, Odocoileus hemionus, does following experimental harassment with an all-terrain vehicle. Canadian Field-Naturalist 102:425-429.
A Varied Response
Helicopter disturbance of wild animals may cause physiological and/or behavioral responses that compromise the animalsø survival, growth and reproductive fitness, ability to raise young, energy budgets, and habitat use. Behavioral responses in animals vary among individuals within a species and between species types; these variations may be due to differences in emperament, sex, age, prior experience with aircraft, or other factors (McKechnie and Gladwin 1994). One relationship is clear between aircraft and behavioral responses: the closer the aircraft the greater the probability that the animal will respond, and the greater the response.
Accidents Happen
Accidental injury of animals that panic and run from aircraft is a common concern of biologists. Occasionally animals, especially young ungulates, will run into objects or fall and get trampled while fleeing from aircraft.
Reproductive Stress
Aircraft disturbances can cause reproductive losses by altering patterns of attendance to young (National Park Service 1994). Both mammals and birds leave their young or eggs exposed to predators and the elements when they run or fly away from aircraft.
Energy Loss
Panic reactions and escape responses to overflights can be energetically îexpensive" to animals for two reasons. First, feeding animals nearly always stop ingesting food when disturbed, which means a decrease in energy intake. Second, disturbed animals usually run or otherwise move away from aircraft, thus increasing their energy expenditure (National Park Service 1994). Increased energy expenditures can reduce the rate of survival and reproduction (Albright and Kunstel 2001). Disturbance from overflights could cause sensitive animals to abandon their habitats. However, more research is needed on the long-term effects of helicopter isturbances.
Associated Impacts
Helicopter recreation raises concern not only about the impact of helicopters themselves but also about associated increases in recreation. Heli-skiing is concentrated in upper-elevation terrain, where goats, caribou, elk, and brown bears occupy habitat. In 1997, a human-triggered avalanche in the Chugach Mountains of Alaska killed a female Brown Bear and her two cubs while hibernating. Likewise, the increase in heli-hiking is taking more people to historically lowuse areas like high alpine or tundra. Alpine habitat is extremely fragile and cannot support such use at high levels; by bringing in groups by helicopter, the numbers and degree of disturbance will increase. Trampled alpine vegetation causes increased stress on wildlife - mountain goats and sheep are particularly vulnerable to this type of disturbance because critical habitat is already in short supply. There are also concerns related to two aspects of brown bear/helicopter/recreational conflicts (ADF&G 1992). First, most individual bears flee approaching helicopters in a full run. If helicopter activity were frequent, bears would most likely move away from a locale (ADF&G 1992). The second concern is for the direct human intrusion into brown bear habitats. Hiking in alpine terrain increases the risk of grizzly/human conflicts. Such conflicts will result in more grizzlies being destroyed in the name of public safety.
Case Studies
Because helicopter recreation is relatively new, review of the literature found few studies that specifically examine the effects of helicopter recreation on wildlife. However, many studies have examined the responses of wildlife to mechanized recreational activities and human disturbances. Therefore, the majority of studies lend themselves to drawing conclusions about the impacts of helicopter recreation.
Perching or nesting birds may flush when disturbed. A study of bald eagles elicited responses from over 40% of eagles when helicopters approached at distances of under 3,050m (Watson 1993). In Alaskaøs Arctic National Wildlife Refuge, heli flights have caused flight/fright behavior in tundra swans and snow geese, and swans have abandoned nests due to the disturbance (Albright and Kunstel 2001). Presence of young in the nest increased tenacity. Eagles, presumably defending their young, did not flush until encounters under 30m (Watson 1993). What seems to be no disturbance and a lack of response to human activities may actually be a form of nest defense (Watson 1993). Even if adults do not flush, regular disruption of nesting activities by aircraft or other human activities (i.e. hiking, skiing, etc.) could result in reduced brooding and feeding of young. This may lead to reduced attentiveness and nest failure (Watson 1993).
A rather significant study in 1982 by Ann Gunn looked at Caribou behavior, range use patterns, and short-term responses to helicopter landings on the Beverly Calving Ground. The study included an experimental disturbance with eight phases: approach, turn, descent, wind-down, shutdown and ground activity, wind-up, take-off, and last audible (Gunn 1982). Gunn found that there were relatively more occasions than expected when caribou exhibited maintenance behaviors or behavioral responses to the helicopter (Gunn 1982). For example, Caribou responded to the helicopter by galloping and trotting during the turn phase. The results from the experimental landings showed that the cows and calves were readily displaced and their activity patterns interrupted even by landing at a distance of 300-2200m away from them. Overall, the study found that helicopter landings within several hundred meters of early post-calving groups or aggregations of caribou will 1) disrupt ongoing maintenance activities; and 2) elicit behavioral responses that lead to displacements from the immediate range to distances of, at least, 1-3km.
A study in 1987 by biologists from Northern Arizona University investigated whether helicopter activities in Grand Canyon National Park affected the feeding behavior of bighorn sheep (Stockwell and Bateman 1991). They found that in the presence of helicopters, sheep were taking in less energy and expending more. Specifically, sheep spent 14% less time feeding during the spring and 42% less in the winter. Meanwhile, the sheep walked 50% more while feeding (McKechnie and Gladwin 1994).
Conclusion & Recommendations
There is a general consensus in the literature that helicopter traffic is more disruptive than fixed-wing overflights (Watson 1993, Albright and Kunstel 2001, Harrington and Veitch 1991, Belanger and Bedard 1989). The literature indicates that flight altitude, noise output, speed, and approach pattern are the most important factors in determining an animaløs reaction to an overflight (McKechnie and Gladwin 1994). Review of current literature and information suggests the following regulations to mitigate impacts of helicopter recreation:
- Zoning of wild lands to assure that critical habitats and opportunities for non-motorized recreation are not lost to industrial, commercial recreation or inappropriate private uses.
- Any action requiring permitted helicopter activities (i.e. helicopter flight seeing, glacier landings, etc.) should have above ground level flight restrictions imposed and enforced. Scientific research indicates a 2 km above ground level no-fly zone to completely avoid harassment of wildlife.
- Minimum distance guidelines of 300m for aircraft flying over sheep, goat, and caribou habitat. Aircraft should keep a quarter of a mile distance from eagleøs nests.
- Knowledge of species in an area that could be affected by helicopter recreation should be obtained. Flight paths and landing sites should be established to minimize contact with wildlife and should avoid surprising (i.e. popping over cliffs) or flying directly at animals. The seasons, habitat ranges, and specific periods when consequences of disturbance are particularly high (i.e. breeding season) should also be considered when planning flight paths.
- When planning management strategies a precautionary approach should be taken and focus should be on the reactions of the most sensitive species.
--- Emily Yeomans is a graduate student in Environmental Studies at the Univ. of Montana and a longtime outdoor educator who has seen the effects of helicopter recreation first hand.
References
Albright, J. and M. Kunstel. 2001. A Research Report for the Jackson Hole Conservation Alliance. Jackson, WY.
Anderson, D. E., O.J. Rongstad, W.R. Mytton. 1990. Home-range changes in raptors exposed to increased human activity levels in southeastern Colorado. Wildlife Society Bulletin 18(2):134-142.
Belanger, L. and J. Bedard. 1989. Responses of staging greater snow geese to human Disturbance. Journal of Wildlife Management 53(3):713-719.
Bunnell, F.L., D. Dunbar, L. Koza, and G. Ryder. 1981. Effects of disturbance on the productivity and numbers of white pelicans in British Columbia¤observations and models. Colonial Waterbirds 4:2-11.
Callanan, L. 1993. Heli-hiking in the bugaboos. Forbes 151:166-170.
Cassirer, E. F., D.J. Freddy, and E.D. Ables. 1992. Elk Responses to disturbance by cross-country skiers in Yellowstone National Park. Wildlife Society Bulletin 20:375-381.
Delaney, D.K., T.G. Grubb, P. Beier, L.L. Pater, and M.H. Reiser. 1999.
Effects of helicopter noise on Mexican Spotted Owls. Journal of Wildlife Management 63:60-76.
Ferguson, M.A.D., and L.B. Keith. 1982. Influence of Nordic skiing on distribution of Moose and Elk in Elk Island National Park, Alberta. Canadian Field-Naturalist 96(1):69-78.
Gladwin, D.N., D.A. Asherin, and K.M. Manci. 1987. 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. NERC-88/30. U.S. Fish and Wildl. Serv., National Ecology Research Center, Fort Collins, CO. 24pp.
Gunn, A. 1983. Caribou Behavior, Range Use Patterns, and Short-Term Responses to Helicopter Landings on the Beverly Calving Ground, N.W.T. Yellowknife Wildlife Service, Northwest Territories, Renewable Resources.
Harrington, F.H. and A.M. Veitch. 1991. Short-term impacts of low-level jet fighter training on Caribou in Labrador. Arctic 44(4):318-327.
Hilderbrand, G.V., L.L. Lewis, J. Larrivee, and S.D. Farley. 2000. A denning brown bear, Ursus arctos, sow and two cubs killed in an avalanche on the Kenai Peninsula, Alaska. Canadian Field-Naturalist 114(3):498.
Johnson, B. 1977. The effects of human disturbance on a population of harbor seals. In Environmental Assessment of the Alaskan Continental Shelf, 422-431. Annual Reports of Principal Investigators for the Year Ending March 1977, Vol. 1, Receptors-Mammals.
Jope, K. L. 1985. Implications of grizzly bear habituation to hikers. Wildlife Society Bulletin 13:32-37.
Knight, R.L., and K.J. Gutzwiller. 1995. Wildlife and Recreationists: Coexistence through Management and Research. pp. 51-156. Island Press.
Krausman, P.R., B.D. Leopold, and D.L. Scarbrough. 1986. Desert mule deer response to aircraft. Wildlife Society Bulletin 14:68-70.
Little, J.B. 1999. Quiet! The sounds of nature are harder to hear. Wilderness 21-25.
MacArthur, R.A., V. Geist, and R.H. Johnston. 1982. Cardiac and behavioral responses of mountain sheep to human disturbance. Journal of Wildlife Management 46:351-358.
Maffly, Brian. 2000. Forest Service Upholds Copter-Ski Ruling. Salt Lake Tribune, Jan. 6th, 2000.
Maffly, Brian. 2000. Compromise on Heli-Skiing Pleases Nobody. Salt Lake Tribune, Jan. 3rd, 1999.
McKechnie, A. and D. Gladwin. 1994. Helicopters and Wildlife. Rotor and Wing 32-33. Miller, F.L., E. Broughton, and A. Gunn. 1988. Mortality of Migratory Barren-Ground Caribou on the Calving Grounds of the Beverly Herd, Northwest Territories, 1981-83. Ottawa: Canadian Wildlife Service Occasional Paper No. 66.
National Park Service. 1994. Report to Congress: Report on Effects of Aircraft Overflights on the National Park System. Denver Service Center.
Phillips, G.E. and A. W. Alldredge. 2000. Reproductive success of elk following disturbance by humans during calving season. Journal of Wildlife Management 64(2):521-530.
Stockwell, C.A., G.C. Bateman, and J. Berger. 1991. Conflicts in national parks: a case study of helicopters and bighorn sheep time budgets at the Grand Canyon. Biological Conservation 56:317-328.
Thiel, R.P., S. Merrill, and L.D. Mech. 1998. Tolerance by Denning Wolves, Canis lupus, to Human Disturbance. Canadian Field-Naturalist 112(2):340-342.
Titus, K. 1992. Letter to the USDA Forest Service. Alaska Department of Fish and Game. Douglas, AK.
U.S. Department of Agriculture. 1999. Final environmental impact statement for the Wasatch Powderbird Guides permit renewal. Wasatch-Cache National Forest, Salt Lake City, UT and Unita National Forest, Provo, UT. pp.3-35-3-40.
U.S. Department of Agriculture. 1997. Helicopter Landings in Wilderness: Final Environmental Impact Statement. Alaska Region, Tongass National Forest. Chatham, Stikine, and Ketchikan Areas. RM-MB-340a.
Watson, J.W. 1993. Responses of nesting bald eagles to helicopter surveys. Wildlife Society Bulletin 21:171-178.
Wilson, S.F. and D.M. Shakleton. 2001. Backcountry Recreation and Mountain Goats: A Proposed Research and Adaptive Management Plan. Wildlife Research Group, University of British Columbia, Vancouver, BC.
Yarmoloy, C., M. Bayer, and V. Geist. 1988. Behavior responses and reproduction of mule deer, Odocoileus hemionus, does following experimental harassment with an all-terrain vehicle. Canadian Field-Naturalist 102:425-429.