125 
Ecological Relationships 
of the Inland Tundra Avifauna 
near Prudhoe Bay, Alaska 
DAVID W. NORTON* 
Institute of Arctic Biology 
University of Alaska 
Fairbanks, Alaska 99701 
IRVIN W. AILES 
Department of Wildlife and Fisheries 
University of Alaska 
Fairbanks, Alaska 99701 
JAMES A. CURATOLO 
Alaska Cooperative Wildlife Research Unit 
University of Alaska 
Fairbanks, Alaska 99701 
Introduction 
Two motivations prompted a quantitative 
study of terrestrial birds at Prudhoe Bay. The 
first was a basic comparison of abundance, 
species composition, diversity, phenology, and 
productivity at that site with similar observa- 
tions at Point Barrow, Devon Island, and other 
northern sites where birds have been studied in 
relation to their resources. The second purpose 
was to examine generally the applied problems 
of tundra birds’ coexistence with recent and 
projected oil and gas developments in arctic 
North America. 
The nearest well-known avifauna is that of 
Point Barrow, some 320 km WNW of Prudhoe 
Bay. A series of behavioral, ecological, and 
energetic studies of various species has been 
under way since the early 1950s. Information 
generated by these studies has been enveloped 
by the U.S. Tundra Biome, resulting in an evalua- 
tion of the Barrow avifauna in the broad eco- 
systems context. We now know that the unique 
species composition and trophic dynamics there 
are the result of a largely saprovore-based food 
chain. That is, many of the terrestrial avian 
consumers depend on soil-dwelling, saprovorous 
arthropods, principally the dipteran families 
Tipulidae and Chironomidae (Holmes 1966; 
MacLean and Pitelka 1971; Norton 1973). 
Breeding shorebirds dominate the tundra in sum- 
mer, as they seem especially capable of acquiring 
soil-dwelling larvae and surface-dwelling adult 
insects in quantities sufficient to support the 
high energy requirement of breeding in cold 
environments. 
The factors making insectivory a feasible 
strategy for breeding birds at Barrow appear to 
be the unusual proportion of primary produc- 
tion entering the litter category susceptible to 
consumption by saprovores, the consequent high 
standing crops of larval saprovores, and the 
interdigitation of moist and dry tundra on a fine 
scale (‘‘fine-grained mosaic’’ of MacLean 1969) 
that permits birds to select from radically dif- 
ferent feeding habitats within short distances. 
Prudhoe Bay tundra differs from that of 
Barrow, lacking the extreme variability of micro- 
relief and moisture over short distances. Never- 
theless, we expected an important saprovore- 
based trophic system favoring a_shorebird- 
dominated avifauna at Prudhoe Bay. 
*Current address: Outer Continental Shelf Project, University of Alaska, Fairbanks, Alaska 99701. 
