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G.L. Hunt

Publications and source records attributed to G.L. Hunt.

6 recordsLinked to original sources
USGS2008

Seasonal and distributional patterns of seabirds along the Aleutian Archipelago

The Aleutian Archipelago is of global importance to seabirds during the northern summer, but little is known about seabird use of these waters during winter. We compare summer and winter abundances of seabirds around 3 islands: Buldir in the western, Kasatochi in the central, and Aiktak in the eastern Aleutians. The density of combined seabird biomass in nearshore marine waters was higher in summer than in winter at Buldir and Kasatochi, but was higher in winter at Aiktak, despite the departure of abundant migratory species. Comparing foraging guilds, we found that only piscivores increased at the western and central sites in winter, whereas at the eastern site several planktivorous species increased as well. The only planktivore remaining in winter at the central and western sites in densities comparable to summer densities was whiskered auklet Aethia pygmaea. Crested auklet Aethia cristatella and thick-billed murre Uria lomvia showed the greatest proportional winter increase at the eastern site. The seasonal patterns of the seabird communities suggest a winter breakdown of the copepod-based food web in the central and western parts of the archipelago, and a system that remains rich in euphausiids in the eastern Aleutians. We suggest that in winter crested auklets take the trophic role that short-tailed shearwaters Puffinus tenuirostris occupy during summer. We hypothesize that advection of euphausiids in the Aleutian North Slope Current is important for supporting the high biomass of planktivores that occupy the Unimak Pass region on a year-round basis. ?? Inter-Research 2008.

Marine Ecology Progress Series↗
USGS2005

Prey consumption and energy transfer by marine birds in the Gulf of Alaska

We investigated prey consumption by marine birds and their contribution to cross-shelf fluxes in the northern Gulf of Alaska. We utilized data from the North Pacific Pelagic Seabird Database for modeling energy demand and prey consumption. We found that prey consumption by marine birds was much greater over the continental shelf than it was over the basin. Over the shelf, subsurface-foraging marine birds dominated food consumption, whereas over the basin, surface-foraging birds took the most prey biomass. Daily consumption by marine birds during the non-breeding season ("winter") from September through April was greater than daily consumption during the breeding season, between May and August. Over the shelf, shearwaters, murres and, in winter, sea ducks, were the most important consumers. Over the basin, northern fulmars, gulls and kittiwakes predominated in winter and storm-petrels dominated in May to August. Our results suggest that marine birds contribute little to cross-shelf fluxes of energy or matter, but they do remove energy from the marine system through consumption, respiration and migration. ?? 2005 Elsevier Ltd. All rights reserved.

Conference Paper↗
USGS1993

Status and ecology of kittiwakes ( Rissa tridactyla and R. brevirostris ) in the North Pacific

Black-legged Kittiwakes ( Rissa tridactyla ) are widely distributed in the subarctic North Pacific and adjacent seas, with a total breeding population of about 2.6 million individuals. Red-legged Kittiwakes ( R. brevirostris ) breed in four locations, and at least 95% of their estimated world population of 230,000 birds nest on one island (St. George, Pribilof Islands). Compared to Black-legged Kittiwakes in Britain, both species in Alaska have exhibited poor productivity since at least the mid-1970s. The situation worsened during the 1980s, with recent (1985-1989) estimates of annual productivity averaging 0.19 young per nest. The frequency of "colony failures" (<0.1 young per nest) exceeded 50% in Alaska between 1985 and 1989. Low productivity has involved, to varying degrees, the failure of many birds to lay eggs, reduced clutch sizes, low hatching success, and poor chick survival. There is evidence of population declines in some colonies of Black-legged Kittiwakes, but other colonies appear to be stable or increasing. High adult survival may account for the relative stability of Black-legged Kittiwakes, but widespread declines are anticipated unless productivity improves. The evidence suggests that poor productivity results from low surface availability of key prey species.

Conference Paper↗
USGS1981

Pelagic distribution of marine birds in the Eastern Bering Sea

Analyses of the most abundant marine bird species in the eastern Bering Sea indicate that their distribution and abundance are the result of complex interactions between biotic and abiotic elements of the environment. Of particular importance are the effects of ice systems, food availability, oceanographic frontal systems, and the location of suitable nesting sites. For most species, the southern ice edge acts as a barrier to northward movement in the spring. OCSEAP surveys indicate that previous estimates of seabird populations in the Bering Sea are probably extremely conservative and that more than 40 million seabirds may occupy these marine waters during the summer months.

Book chapter↗