Geology topics

Margaret R. Petersen

Publications and source records attributed to Margaret R. Petersen.

42 records · Page 3Linked to original sources

USGS1982

Population and status of Emperor Geese along the north side of the Alaska Peninsula

We gathered information on the timing of spring and autumn migration of Emperor Geese Anser canagicus from Nelson Lagoon, the age ratios of geese during autumn migration, and the numbers of geese in estuaries along the north side of the Alaska Peninsula and Bristol Bay during spring and autumn migration. Birds staged in most of the lagoons and bays along the north side of the Alaska Peninsula, but Nelson Lagoon and Seal Islands Lagoon were the most heavily used. Geese concentrated in Nelson Lagoon for about six to eight weeks in both spring and autumn. We suspect that the population of Emperor Geese in Alaska may have declined by as much as 34% between the 1960's and 1981. Although the average number of young per successful breeding pair has remained high during this period, the overall proportion of young in the population has been extremely low, at least during the past five years. More studies are necessary to determine factors influencing the status of this species.

Alaska↗

USGS1981

Birds of the northcentral Alaska Peninsula, 1976-1980

Between spring 1976 and fall 1980 we studied the occurrence, abundance, and habitat use of birds over a 2000 square km segment of the northcentral Alaska Peninsula. During this period observers were present 473 days and obtained records for all seasons. A total of 125 species was recorded; 63% (79 of 125) were water-associated. The breeding avifauna was found to be a mixture of Panboreal (49%), North American (34%), and Aleutican (17%) species. The Aleutican group was dominant in terms of biomass and numbers of individuals during the nonbreeding period. Forty-two species were confirmed breeding in the area and another 19 were suspected of breeding. The majority of birds occurred as migrants; 14 species were considered permanent residents and an additional 20 were winter residents. ... The area is a principal late summer and fall molting and staging area for several species of arctic and subarctic nesting waders and seaducks and emperor geese .... From late September through mid-October the density of water birds over the entire littoral and nearshore area approached 1000 birds square km. This density was exceeded many fold for certain species on particular segments of habitats in the area.

Alaska↗

USGS1981

Populations, feeding ecology and molt of Steller's Eiders

This study considers the temporal and spatial distribution of Steller's Eiders ( Polysticta stelleri ) during molt along the north side of the Alaska Peninsula from Port Heiden to Bechevin Bay. Subadult eiders molted primarily at Nelson Lagoon, adult males at Nelson Lagoon and Izembek Bay, and adult females primarily at Izembek Bay. Only a few eiders used Bechevin Bay, Seal Islands, and Port Heiden. Although the flightless period overlapped among different age and sex classes, subadults were flightless first, then adult males, and last, adult females. Eiders maintained spatial and temporal separation during the flightless period, thereby reducing competition for food resources. Eiders at Nelson Lagoon were observed feeding only by head-dipping during the pre-flightless period in 1979, a significant change from 1977 when they fed both by diving and dipping. During both 1977 and 1979 eiders foraged for approximately equal amounts of time during each stage of molt. Foods consisted primarily of bivalve mollusks and amphipods. These foods were consumed in different proportions before and after the wing-feather molt, with mussels being most important when eiders were growing remiges. Comparisons between the amount of energy in blue mussels ( Mytilus edulis ), clams ( Macoma balthica ), and gammarid amphipods showed that mussels yield the most energy per gram of whole wet weight. Apparently Steller's Eiders have adjusted to the increased energy demands of molt by eating invertebrates with high caloric content, rather than by increasing the amount of time feeding.

Alaska↗

USGS1981

An annotated bibliography of literature on Alaska water birds

The demand for information on birds in Alaska has surged within the past few years, primarily because of the need to adequately assess the impacts of a wide range of planned developments. The accompanying increase in studies of avian populations has resulted in a growing need for a comprehensive bibliography of Alaska ornithology. An initial effort by Bartonek and Lensink (1978) provided a list of published and unpublished references on marine birds, but this list was only marginally useful because it lacked adequate indexing and annotation of references cited. Their bibliography, however, plus those of Cade (1953) and Gabrielson and Lincoln (1959), provided the basis and primary reference sources for our work. In the present bibliography we have attempted to compile all substantive references addressing water birds in Alaska because this group of birds appears to be most Vulnerable to repercussions of development, particularly along the coast. However, the works cited make up an estimated 70-80% of all literature on birds in Alaska, and this volume thus provides an initial source of references on terrestrial birds. This bibliography, which contains 1554 citations, is current for most journal sources through 1979 and most of 1980. The content of each paper has been summarized, and we have indexed the citations by subject, species, and geographic location to make the bibliography a more useful reference. Furthermore, the bibliography has been designed to facilitate future inclusion of references that have been omitted or that will be published in the rapidly growing body of literature on Alaska birds.

Alaska↗

USGS1980

Observations of wing-feather molt and summer feeding ecology of Steller's Eiders at Nelson Lagoon, Alaska

The population size, moult chronology, food habits, and feeding behaviour of Steller's Eiders Polysticta stelleri were studied at Nelson Lagoon, Alaska from May to October 1977. Sub-adults were flightless from late July to late August and the adult males were flightless from late August to mid September. Adult females were rarely flightless at Nelson Lagoon but commonly flightless at Izembek Bay. Steller's Eiders ate primarily bivalve mollusca and amphipod crustacea, with Mytilus edulis and Anisogammarus pugettensis the most important foods. Eiders took amphipoda prior to the wing-feather moult, bivalves during the wing-feather moult, and both types of invertebrates after the wing-feather moult. Steller's Eiders fed primarily at the low tide by diving (flock-feeding) or head-dipping, both during the day and at night. There was no difference in feeding behaviour between ages or sexes. Eiders fed almost exclusively by diving after the wing-feather moult and apparently fed more as the season progressed.

Alaska↗

USGS1979

Nesting ecology of Arctic loons

Arctic Loons were studied on the Yukon-Kuskokwim Delta, Alaska, from the time of their arrival in May to their departure in September, in 1974 and 1975. Pairs arrived on breeding ponds as soon as sufficient meltwater was available to allow their take-off and landing. Loons apparently do not initiate nests immediately after their arrival, even when nest-sites are available. Delayed egg-laying may be dependent on a period of yolk formation. Delaying yolk formation until after arrival on nest ponds is an adaptation by loons to the variable time suitable habitat becomes available for nesting. Predation of eggs by Glaucous Gulls, Long-tailed and Parasitic jaegers and foxes varied in relation to the location of the nest-site, and the availability of alternate prey. Hatching success was the lowest recorded for Arctic Loons (5%) in 1974, when eggs of both loons and Cackling Geese were taken in large numbers by predators. Hatching success increased to 32% in 1975 when an abundance of tundra voles was observed. No loon eggs hatched after the hatching of the Cackling Goose eggs when this alternate prey was no longer available. Nests destroyed by foxes were predominantly along shorelines, and those by gulls and jaegers were predominantly on islands. Nest-site selection by Arctic Loons may reflect an adaptive response to varying selective pressures by their predators.

Alaska↗