Nondigestible items included bits of plastic, 
rubber, cork, and wire insulation. It is tempting 
to conclude that the differences in nondigesti- 
bles found in the two areas, Deadhorse and 
Point McIntyre (Table 2), are related to the 
differences in degree of human activity. How- 
ever, it should be noted that in the Point 
McIntyre area, an abandoned DEW-Line site and 
the remains of oil exploration activities conduct- 
ed at a time when environmental issues were not 
as popular as at present, have resulted in at least 
an equal availability of nondigestible items in 
the two areas. 
Discussion 
During the breeding season, adult foxes ap- 
pear to spend large blocks of time away from 
the den site; they are infrequently seen in the 
denning area. These observations can be explain- 
ed if one assumes that breeding foxes occupy 
large, overlapping feeding ranges. The use of 
swan eggs as food for fox pups fits this assump- 
tion. During the summer of 1971, ornithologists 
were documenting the nest locations of birds in 
the Deadhorse area. It is doubtful that breeding 
swans, whose large size and white color make 
them quite conspicuous on the treeless tundra, 
could have escaped detection at the time the 
eggs appeared at the fox den. The nearest known 
swan nest, 13 km from the den site, was not 
predated during July 1972. Thus, in this case at 
least, adult foxes probably traveled more than 
13 km to secure food for the den. The impact of 
foxes On populations of small mammals and 
nesting birds is probably spread over an area of 
at least 500 square km. It should be reempha- 
sized that the lemming population was relatively 
low during these years, which may have influ- 
enced the size of the feeding range. Considerably 
more data are needed on range size and prey 
species utilization before definitive statements 
can be made on the impact of the arctic fox on 
small mammal and bird populations. 
149 
Acknowledgments 
These observations were conducted in con- 
junction with a Barrow based research project 
sponsored through the Arctic Institute of North 
America (AINA) and the NSF Tundra Biome 
grant to the University of Alaska. Support at 
Prudhoe was provided by the Tundra Biome 
Center through Prudhoe Bay Environmental 
Subcommittee funding. 
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