245. 
246. 
247. 
effects of noise on animals is pre- 
sented. Wildlife exposures to noise 
are generally involuntary and come 
from mobile sources such as airplanes 
and recreational vehicles. 
BOATING, OFF-ROAD VEHICLES, FLIGHT DIS- 
TANCE, RECREATION MANAGEMENT, U.S. BLM 
LANDS, WILDLIFE (GENERAL) 
Jarvinen, J. A., and W. OD. Schmid. 
1971. Snowmobile use and winter mor- 
tality of small mammals. Pages 131- 
141 in M. Chubb, ed. Proceedings of 
the 1971 Snowmobile and Off the Road 
Vehicle Research Symposium, 14-15 June 
1971, East Lansing, Mich. Michigan 
State Univ., East Lansing, Dept. Park 
Recr. Resour. Tech. Rep. 8. 
Trapping results in Minnesota showed 
increased winter mortality of small 
mammals beneath snowmobile-compacted 
snowfields. It is suggested that com- 
paction inhibits mammal movements be- 
neath snow and subjects subnivean or- 
ganisms to greater temperature stress. 
OFF-ROAD VEHICLES, FORESTS, MAMMALS 
Jehl, J. R., Jr. 1973. Studies of a 
declining population of brown pelicans 
in northwestern Baja California. Con- 
dor 75:69-79. 
Large-scale reproductive failures of 
Baja California brown pelican colonies 
were found during studies from 1969 
through 1971. Thin-shelled eggs are 
the major cause of reproductive fail- 
ure, but human disturbance is also im- 
portant. Tourists in yachts and other 
pleasure craft visit some colonies, 
usually inadvertently disturbing 
breeding pelicans. The Mexican and 
United States governments could im- 
prove the chances for the birds’ sur- 
vival by limiting access to breeding 
colonies. 
BOATING, TOURISM, RESEARCH IMPACTS, 
WILDLIFE VIEWING, COASTAL ZONES, THREAT- 
ENED AND ENDANGERED SPECIES, RECREATION 
MANAGEMENT, BROWN PELICAN 
Jehl, J. R., Jr. 1977. History and 
present status of ospreys in north- 
western Baja California. Pages 241- 
245 in J. C. Ogden, ed. Transactions 
of the North American Osprey Research 
Conference, 10-12 February 1972, Wil- 
46 
248. 
249. 
liamsburg, Va. U.S. Natl. Park Serv. 
Trans. Proc. Ser. 2. 
Although osprey populations on the 
west coast of Baja California, Mexico, 
have remained fairly stable since 
1946, human interference is a continu- 
al threat to birds nesting in the 
area, particularly on the offshore is- 
lands. Increasing visits by pleasure 
boats bring curious sightseers who may 
cause losses of eggs to gull predation 
by flushing adults from nests. 
TOURISM, WILDLIFE VIEWING, 
ZONES, PREDATION, OSPREY, GULLS 
COASTAL 
Jenni, D. A. 1969. A study of the 
ecology of four species of herons dur- 
ing the breeding season at Lake Alice, 
Alachua County, Florida. Ecol. Mono- 
gr. 39:245-270. 
The effects of the investigator on 
herons were evaluated during studies 
of heron ecology in Florida. Some 
losses occurred from flushing adults 
from nests with subsequent loss of 
young, but indirect effects may have 
been more important. Nestlings often 
regurgitated when disturbed, and the 
youngest nestlings frequently died of 
starvation. However, production data 
and other observations suggest that 
the impact of the investigator on her- 
on survival was not great. 
RESEARCH IMPACTS, WETLANDS, 
SNOWY EGRET, CATTLE EGRET, 
HERON, LOUISIANA HERON 
PREDATION, 
LITTLE BLUE 
Johnson, A. S. 
National Parks. 
Mag. 46(2):10-15. 
1972. Man, grizzly and 
Natl. Parks Conserv. 
Problems of human-grizzly bear inter- 
actions in Yellowstone and Glacier Na- 
tional Parks are discussed in this 
nontechnical article. The history of 
confrontations is outlined and recent 
bear management practices are criti- 
cally reviewed, particularly the feed- 
ing of garbage to bears in Yellow" 
stone. New Park Service programs to 
attain wild, independent grizzly popu- 
lations in parks are commended. 
CAMPING, HIKING, HARASSMENT, TOURISM, 
WILDLIFE VIEWING, FORESTS, HUMAN HEALTH 
AND SAFETY, THREATENED AND ENDANGERED 
SPECIES, WILDLIFE MANAGEMENT, RECREATION 
MANAGEMENT, U.S. NATIONAL PARKS 

