116. 
Lys 
118. 
Conv. Int. Assoc. Game Fish Conserv. 
Comm. 60:97-103. 
Increases in demand for snowmobiles 
and potential impacts on fish and 
wildlife resources are reviewed.  Im- 
pacts of snowmobiles are listed as 
benefits and liabilities; other sec- 
tions discuss registration, regula- 
tion, and education of snowmobile 
users. 
HARASSMENT, OFF-ROAD VEHICLES, FORESTS, 
RECREATION MANAGEMENT, WILDLIFE (GEN- 
ERAL) 
Dorrance, M. J., P. J. Savage, and D. E. 
Huff. 1975. Effects of snowmobiles 
on white-tailed deer. J. Wildl. Man- 
age. 39:563-569. 
In studies of white-tailed deer in 
Minnesota, deer responded to very low 
intensities of intrusion by man and 
snowmobiles. Displacement of deer 
from areas along trails occurred; in 
some cases changes in home range size 
and increased movement were observed. 
It is suggested that the observed 
disturbances could be detrimental to 
deer, especially during severe win- 
ters. 
OFF-ROAD VEHICLES, FORESTS, U.S. 
PARKS AND LANDS, WHITE-TAILED DEER 
STATE 
Douglas, C. L. 1976. Coordination of 
bighorn research and management in 
Joshua Tree National Monument. Trans. 
N. Am. Wild Sheep Conf. 2:1-15. 
In Joshua Tree National Monument, Cal- 
ifornia, decreases in annual precipi- 
tation over the last 20 years have 
caused a large decline in available 
water sources for bighorn sheep. Hu- 
man presence worsens the problem when 
campers and hikers keep sheep away 
from waterholes and cause general ha- 
rassment. Management actions to im- 
prove conditions for bighorn sheep are 
discussed. 
CAMPING, HIKING, HARASSMENT, DESERTS, 
RECREATION MANAGEMENT, WILDLIFE MANAGE 
MENT, U.S. NATIONAL PARKS, BIGHORN SHEEP 
Doyle, P. 1974. Progress made by the 
snowmobile industry since 1971 in 
areas of environmental concern. Pages 
77-85 in D. F. Holecek, ed. Proceed- 
24 
4193 
120. 
ings of the 1973 Snowmobile and Off 
the Road Vehicle Research Symposium. 
Michigan State Univ., East Lansing, 
Dept. Park Recr. Resour. Tech. Rep. 9. 
Results of two industry-funded studies 
are reported in support of claims that 
snowmobiles produce negligible impacts 
on the environment. One project in 
Wisconsin determined that telemetered 
deer and rabbits increased movements 
during snowmobile activity periods, 
but did not change home range size; 
another study found minimal impacts of 
snowmobile use on non-forest vegeta- 
tion. 
OFF-ROAD VEHICLES, HARASSMENT, FORESTS, 
RECREATION MANAGEMENT, U.S. STATE PARKS 
AND LANDS, WHITE-TAILED DEER, EASTERN 
COTTONTAIL 
Drent, R. H., and C. J. Guiguet. 1961. 
A catalogue of British Columbia sea- 
bird colonies. British Columbia Pro- 
vincial Museum, Victoria, Occ. Pap. 
12. 173 pp. 
Distribution and nesting habits of 
seabirds in British Columbia and im- 
pacts of human disturbance at colonies 
are discussed. The increase in the 
use of motorboats for fishing and 
touring along the coast has made colo- 
nies more accessible; as a result, 
curious sightseers often frighten 
adult birds from nests, leading to 
losses of eggs and young from preda- 
tion by crows and gulls. Regulation 
of visitation and public education are 
necessary to prevent disturbance. 
BOATING, TOURISM, WILDLIFE VIEWING, 
COASTAL ZONES, PREDATION, RECREATION 
MANAGEMENT, SEABIRDS, NORTHWESTERN CROW 
Drury, W. H. 1979. Population dynamics 
in northern marine birds. Pages 123- 
139 in J. C. Bartonek and D. N. Net- 
tleship, eds. Conservation of marine 
birds of northern North America. Pa- 
pers from the International Symposium, 
13-15 May 1975, Seattle, Wash. U.S. 
Fish Wildl. Serv. Wildl. Res. Rep. 11. 
Theoretical aspects of marine bird 
population dynamics in relation to hu- 
man disturbance are discussed. It is 
likely that even undisturbed popula- 
tions fluctuate considerably due to 
specific species strategies and 
changes in the marine environment. 

