134. 
135, 
136. 
A project begun in 1976 studied human 
disturbance of bighorn sheep in Cali- 
fornia. Human use of the area includ- 
ed backpacking and climbing. Hikers 
camped in very limited areas associ- 
ated with the trail, water, and trees: 
climbers had the greatest potential 
effects on sheep. The levels of jin- 
trusion did not appear to be adversely 
affecting sheep, but if the number of 
users is allowed to increase the ef- 
fects on sheep should be closely moni- 
tored. 
CAMPING, CLIMBING, HIKING, WILDLIFE 
VIEWING, TUNDRA, RECREATION MANAGEMENT, 
BIGHORN SHEEP 
Ellison, L. N., and L. Cleary. 1978, 
Effects of human disturbance on breed- 
ing of double-crested cormorants. Auk 
95:510-517. 
Studies in the St. Lawrence estuary 
assessed the influence of investiga- 
tors on cormorants. Frequent visits 
to colonies during the breeding season 
caused nest abandonment and gull pre- 
dation, and discouraged late-nesting 
birds from settling in disturbed colo- 
nies. Birds were less susceptible to 
disturbance in the second year of the 
study. 
RESEARCH IMPACTS, TOURISM, PREDATION, 
COASTAL ZONES, DOUBLE-CRESTED CORMORANT, 
HERRING GULL 
Enderson, J. H., and J. Craig. 1974. 
Status of the peregrine falcon in the 
Rocky Mountains in 1973. Auk 91:727- 
736. 
Factors responsible for an apparent 
decline in the numbers of peregrine 
falcons in the central Rocky Mountains 
are discussed. Pesticides appear to 
be the major factor; human distur- 
bances such as rock climbing, picnick- 
ing, and highways may be important lo- 
cally but are not widespread enough to 
explain the general decline. 
CLIMBING, PICNICKING, FORESTS, RANGE- 
LAND, THREATENED AND ENDANGERED SPECIES, 
PEREGRINE FALCON 
Engel, J. M., F. R. Courtsal, R. L. Mar- 
tin, J. R. Messerli, T. H. Hooper, R. 
E. Mumford, and L. E. Terry. 1975. 
Recovery plan for the Indiana bat. 
at 
134, 
138. 
U.S. Fish and Wildlife Service, Wash- 
ington, D.C. 34 pp. plus comments and 
a memorandum. 
Data concerning the biology, ecology, 
and status of the endangered Indiana 
bat, and management plans to accom- 
plish the recovery of the species, are 
outlined. Human disturbances to vul- 
nerable winter populations are consid- 
ered the major cause of population de- 
cline. Vandalism and inadvertent dis- 
turbance by spelunkers and biologists 
have been responsible for measurable 
declines jin several instances. 
HARASSMENT, SPELUNKING, RESEARCH IM- 
PACTS, TOURISM, THREATENED AND ENDANGER- 
ED SPECIES, RECREATION MANAGEMENT, WILD- 
LIFE MANAGEMENT, INDIANA BAT 
Erwin, R. M. 1980. Breeding habitat 
use by colonially nesting waterbirds 
in two mid-Atlantic U.S. regions under 
different regimes of human distur- 
bance. Biol. Conserv. 18:39-51. 
Nesting habitat selection by four spe- 
cies of seabirds was compared between 
New Jersey and Virginia. Low seabird 
use of barrier islands along the more 
disturbed New Jersey coast suggests 
that human disturbance causes seabirds 
to nest in less preferred habitats. 
Effects of the habitat shift on sea- 
birds are discussed. 
HIKING, OFF-ROAD VEHICLES, COASTAL 
ZONES, PREDATION, U.S. NATIONAL PARKS, 
U.S. NATIONAL WILDLIFE REFUGES, HERRING 
GULL, BLACK SKIMMER, COMMON TERN, LEAST 
TERN 
Evans, R. D., and C. W. Wolfe, Jr. 1967. 
Effects of nest searching on fates of 
pheasant nests. J. Wildl. Manage. 31: 
754-759. 
Data from 1,276 pheasant nests were 
analyzed to determine the effect of 
nest searching on nest fate. Nests 
where a visit resulted in the hen 
flushing had the highest abandonment 
rate, and nests where a hen was pres- 
ent during the visit but did not flush 
had the highest percent success. How- 
ever, active nest visits compared to 
nests terminated before the visit sug- 
gested that nest visitation had a neg- 
ligible effect on nest fate. 
RESEARCH IMPACTS, RANGELAND, 
RING-NECKED PHEASANT 
PREDATION, 
