• Blood organochlorines, immune function and health of free-ranging northern fur seal pups (Callorhinus ursinus)

      Beckmen, Kimberlee Beth; Blake, John E. (1999)
      This study examined organochlorine (OC) contaminant levels in blood and milk along with immune function and health of northern fur seals ( Callorhinus ursinus) from St. George Island, Alaska. This portion of the Pribilof Islands breeding stock has undergone a long-term decline between 4 and 6% per year for unknown reasons. To examine the possible role of neonatal OC exposure on health, two cohorts of pups (69 total) and 33 matched periparturient dams were captured for blood and milk sample collection. From the second cohort of 49 neonates, 43 were re-sampled 29 to 51 days later. OCs were extracted from whole blood and milk to identify 15 polychlorinated biphenyl (PCB) congeners and 4 metabolites of dichloro-diphenyl-trichloroethane by high performance liquid chromatography. Peripheral blood lymphocytes were isolated and cryopreserved for in vitro lymphoproliferative immunoassays. These cellular function assays, along with complete blood cell counts, growth rates and survival through the early developmental period, were used as indicators of health status. Humoral immune function was assessed by in vivo antibody responses to tetanus vaccination. Mean blood levels of PCBs were higher in neonate samples than in pups one to two months old. Seven of the eight congeners detected in blood were higher (lipid weight) in neonate blood than in dam blood or milk. First-born neonates were exposed to higher levels of OCs from ingested milk and had higher blood levels of OCs than neonates of older, multiparous dams. Higher OC exposure in neonates was correlated to higher blood OC levels and poorer lymphoproliferative responses as well as lowered serum. retinol and thyroxine. Higher proportions of pups born to old dams developed tetanus antibodies compared to the pups of young dams. Higher OC exposure and poor immune responses in first-born pups may indicate a higher risk of secondary morbidity and mortality than for pups born to multiparous dams but an affect on growth rate or survival to midway through the nursing period was not detected. Evidence of substantial OC contaminant exposure at a critical period of development for the immune system must be considered as a potential contributing factor to reduced post-weaning survival.
    • Blood profile of grizzly bears in central and northern Alaska

      Brannon, Robert D. (1983-05)
      Blood from 151 grizzly bears (Ursus arctos) captured between 1973 and 1982 in the Brooks Range, Alaska, and the Alaska Range was examined for 7 hanatological, 24 serum chemistry, and 6 protein electrophoretic determinations. Differences in these characteristics between samples collected one hour apart indicate a response to stress during capture. Location differences in leukocyte count, erythrocyte count, hemoglobin, hematocrit, and cortisol suggest that Alaska Range bears were more stressed by capturing than Brooks Range bears. Sodium, creatinine, and urea nitrogen were negatively correlated with capture date, suggesting varied diet reinstatement and regained renal function as time from den emergence increased. Calcium, phosphorous, and alkaline phosphatase were negatively correlated with age, reflecting increased osteoblast activity and bone formation in young bears. Males had higher values than females for erythrocyte count, hematocrit, glucose, creatinine, calcium, phosphorous, and alkaline phosphatase, while glutamic-oxalacetic and glutamic-pyruvic transaminases were higher in females.
    • Blubber and beyond: the role of lipids in thermoregulation and energy reserves of phocid seals

      Pearson, Linnea E.; Burns, Jennifer M.; Horstmann-Dehn, Larissa-A.; Pfeiffer, David C.; Mellish, JoAnn E.; Buck, C. Loren (2015-08)
      Phocid seals rely on lipids in the form of a blubber layer as insulation and lipids as energy sources in blubber and muscle. The amount and lipid composition of blubber and other lipid stores vary throughout life within and among species of phocid seals. I hypothesized that this variation in regulation, allocation, and interactions among lipid stores is influenced by species, ontogeny, and tissue-specific thermal regimes in polar phocids: harp (Pagophilus groenlandicus), hooded (Cystophora cristata), and Weddell (Leptonychotes weddellii) seals. I investigated the thermoregulatory strategy of neonatal harp, hooded, and Weddell seals, and throughout the transition to an aquatic environment in harp seals. All three species had similar thermal resistance, though it was achieved differently using either lanugo or blubber. While there was variation in the main thermoregulatory strategy among species, no species possessed all thermal adaptations of adults. Harp and Weddell seals had higher surface area to volume ratios (SA:V), thus higher potential heat loss, though compensatory mechanisms for heat production were different between species. Harp seals were the only species with the potential for nonshivering thermogenesis (NST) in brown adipose tissue (BAT), whereas Weddell seals had the highest potential for shivering thermogenesis (ST) in their skeletal muscle. Hooded seals relied on blubber, and had a significantly lower SA:V than the other two species. As harp seal pups develop, their potential for NST declines and they shift to a reliance on blubber for insulation. By late weaning, harp seal pups have similar insulative capabilities as adults, and can likely meet the thermoregulatory challenges associated with living in water. In neonatal and young seals that have little blubber, other lipid stores such as BAT and skeletal muscle lipids provide heat-generating mechanisms (NST or ST) to offset potentially high rates of heat loss. The potential for NST declines with age, as the blubber layer develops in harp seals, and weaned pups look to have similar insulative capabilities as adults. While phocid adults rely on blubber for insulation and maintain a thermal gradient across the tissue, otariids (fur seals and sea lions) instead maintain an external gradient across a thick fur layer. This has implications for the underlying lipid composition of blubber, as the fatty acids (FA) that make up this lipid respond differently to temperature. In phocid blubber, latitude (a proxy for environmental temperature) had a positive correlation with the proportion of polyunsaturated fatty acids, but a negative correlation with saturated fatty acids. In otariids, these trends were reversed. This suggests interactions between blubber and the ambient environment play a role in the overall relative proportions of FA classes in blubber. Unlike in blubber, the FA class composition of harp, hooded, and Weddell seal skeletal muscle was similar among species. In adult female Weddell seals, the relative proportions of individual FA in blubber and muscle were significantly different between tissues; these differences persisted across seasons, and were independent of female reproductive state. It appears that the FA in blubber and muscle reflect the tissues' roles within the body. Blubber contained a greater proportion of monounsaturated FA, which remain fluid at lower temperatures, while the muscle contains a larger proportion of SFA, which produce the greatest amounts of ATP per mole oxidized to support metabolism. In adult phocids, the FA composition of the blubber layer appears to be influenced by environmental interactions with latitude (temperature), in accordance with the location of and steepness of the thermal gradient through the blubber layer. Finally, environment looks to have little influence on the FA stores in skeletal muscle, and seasonally persistent tissue differences between blubber and muscle highlight how lipid is dynamically modulated within the body of phocid seals. How and what lipids are allocated to blubber is a mixture of abiotic and biotic cues throughout life, linked to thermodynamics, ambient environment, and energy dynamics.
    • Body composition (carbon, nitrogen and calories) and energetics of immature walleye pollock, Theragra chalcogramma (Pallas), in the southeast Bering Sea

      Harris, Robert K. (1985-05)
      The body composition (carbon, nitrogen and calories) of Bering Sea and Resurrection Bay (Alaska) immature walleye pollock (9-360 g wet weight) were related to dry weight and Fulton's condition factor index by regression models. The condition factor was a better predictor of body composition than dry weight. As condition improved from a minimum starvation level of 0.42 to a maximum of 1.16, body caloric, percent carbon, and the carbon-nitrogen ratio increased, while percent nitrogen and percent ash decreased. The body composition measurements allowed energy budget terms (assimilation coefficient, growth, and metabolism) to be expressed in common units. The assimilation coefficient and growth terms were estimated from literature sources. Oxygen consumption measurements at 3-10°C yielded the metabolic term. The daily food requirement for 0-3 year old walleye pollock, at their annual average Bering Sea habitat temperature of 3.8°C, was 1.0 - 1.5% of the body weight.
    • Body Condition And Food Resources Of White-Tailed Deer On Anticosti Island, Quebec

      Huot, Jean (1982)
      A study was conducted on relationships between seasonal variation in body condition of white-tailed deer (Odocoileus virginianus borealis) and food resources on Anticosti Island, Quebec. Results of the vegetation surveys show that food resources are extremely limited in abundance and variety as snow covers the ground vegetation in winter. Excluding Picea spp., Abies balsamea is by far the most available browse species, accounting for approximately 95% of the available browse biomass in February and March. Analysis of rumen contents suggests that this species accounts for 98.5% of the browse eaten by inland deer between February and mid-April. Lichens account for 9.5% of the dry weight of the rumen content at that time. During the snow-free period, forbs dominate the diet. Both sexes and all age classes show a well defined pattern in body composition with maximum fat levels occurring between September and mid-December and minimum levels between mid-April and mid-June. Fat reserves (ether extraction) in fawns vary from a maximum of 15.3% in fall to a minimum of 0.2% in spring as they lose 41% of their ingesta-free body weight. Composition of the winter body weight loss varies according to sex and age, fat represents 31.7% to 58.9% of the loss and protein 17.8% to 23.0%, water is inversely correlated with fat and ash is a minor part of the loss. The caloric content of the weight loss on an ingesta-free weight basis is lowest in 3-year-old males (3.95 kcal/g) and highest in 2-year-old females (6.86 kcal/g). It is concluded that in association with their low productivity in summer, Anticosti deer must base their winter survival strategy primarily on energy conservation and secondarily on food acquisition during that season.
    • Body condition and reproductive strategies of female lesser scaup in the boreal forest of Alaska

      DeGroot, Kristin A.; Lindberg, Mark; Barboza, Perry; Schmutz, Joel (2011-05)
      In many waterfowl species, body condition of breeding females can contribute to reproductive success by influencing factors such as egg size, clutch size and ability to incubate eggs. In turn, changes in female condition at the population level could affect population growth rates. Large-scale declines in populations of Lesser Scaup (Aythya affinis) raised concerns that poor female body condition was contributing to declines by reducing reproductive output. However, little was known about changes in body condition over time and about the contribution that stored body reserves make to egg production, especially in boreal forest regions where most scaup breed. My objectives were: 1) examine temporal changes in body condition of pre-breeding female lesser scaup on the Yukon Flats National Wildlife Refuge, Alaska and the relationship between body condition and breeding status; 2) examine the role of body reserves (protein and lipid) in egg production using stable isotope techniques. I found no evidence for a decline in female body condition as compared to historic measures. However, females that had entered rapid follicle growth (the early stages of egg production) were significantly fatter than birds that were not currently producing eggs. In addition, I found that female lesser scaup use both body reserves and dietary nutrients for production of egg yolk.
    • Bone As A Biomarker Of Mercury Exposure In Prehistoric Arctic Human Populations: Initial Method Validation Using Animal Models

      Halffman, Carrin M. (2009)
      Marine mammals are dietary staples among many indigenous peoples of the Arctic, but these foods sometimes contain high levels of mercury, a toxic heavy metal that can cause nerve and brain damage. Because mercury can be released into the environment by both industrial and natural processes, prehistoric marine mammal consumers may have been exposed to this toxicant, but little is known about preindustrial mercury levels. This research examined the potential for using the mercury concentration of archaeological bone as a biomarker of mercury exposure. Two requirements of valid biomarkers of exposure were explored: (1) measurement accuracy (trueness and precision) and (2) correspondence with the extent of exposure. Measurement accuracy was evaluated using repeated determinations of mercury concentration in a sample of modern seal bones. Correspondence with exposure was examined by comparing bone mercury concentration to controlled exposure level in laboratory rats, and to the stable nitrogen isotope ratio (delta15N) (a proxy measure of exposure) in prehistoric ringed seals from Thule-period archaeological sites in Alaska. Results show that mercury measurements have acceptable accuracy and that bone mercury is strongly related to exposure. These promising results suggest that, with further validation on human subjects, bone mercury may provide a reliable archive of mercury exposure in preindustrial archaeological populations.
    • Book clubs in the ESL classroom: a microinteractional analysis of literacy development in adult ESL students

      Johnson, Sharon E.; Carr, Richard; Heyne, Eric; Martelle, Wendy (2016-12)
      This study uses conversation analysis to identify literacy development in adult ESL classroom book club discussions. The investigation focuses on the interactions of three university students participating in a six-week book club about Harry Potter and the Sorcerer's Stone. The longitudinal microethnographic analysis reveals the students' development of interactional routines for enacting topic transitions. Two student strategies are examined: (a) the development of a group routine for reading discussion questions aloud; and (b) the use of the transition markers okay and next. The students' establishment of these strategies during the six meetings provides evidence of literacy development during classroom book club discussions. Additionally, the research adds to the currently small corpus of conversation analysis book club studies. Full transcripts for the six book club meetings are also provided.
    • Border patrol

      Iseri, Erica Keiko (2000-12)
      'Border Patrol deals with people across geographical as well as cultural and linguistic lines.' So reads a sentence from the penultimate story of this thesis. While the main characters are all either Japanese or Japanese-American, and they live in Japan or Southern California or Fairbanks, Alaska, the stories explore such universal issues of love, obligation, and freedom. The characters' ethnicity and place serve mainly to inform the larger themes. The point of view from which the stories are told varies from story to story, from a young third person female to a middle-aged first person male. The amount of time in which the stories take place differs as well, from minutes to decades. The stories themselves, though, concern the characters' struggle for independence from constricting relationships and a search for identity through a passion--golf, music, origami. The line between dependence and inner strength is the border that they walk.
    • Boreal forest regeneration dynamics: Modeling early forest establishment patterns in interior Alaska

      Rupp, Terry Scott; Yarie, John (1998)
      Ecological processes are responsible for vegetation trajectory within the boreal forest landscape of interior Alaska. The reproductive response of boreal forest to disturbance controls vegetation trajectory. Boreal forest reproduction dynamics are influenced by both biotic and abiotic factors, acting upon the spatio-temporal dynamics of the landscape. Understanding these factors and how the boreal forest responds, both spatially and temporally, is critical for the development of accurate models of regional and global vegetation dynamics. I developed a geographic model of the early post-disturbance seedling regeneration pattern of upland white spruce ecosystems in interior Alaska. The model was developed and runs within a geographic information system (GIS). The model simulates the establishment patterns of white spruce, paper birch, and aspen across the landscape following fire. Seed production and dispersal, disturbance effects upon the seedbed, and the early establishment of both seedlings and vegetative stems are simulated. The model was used to simulate a 6 yr period (1983-1988) of seedling establishment at the Bonanza Creek Experimental Forest near Fairbanks, following the Rosie Creek fire. Correlation values between predicted and established seedlings were high, demonstrating the model's ability to simulate general establishment patterns. Sensitivity analysis revealed seed production, seed source location and orientation, and seedbed "receptivity" as important controls upon the early establishment success of white spruce seedlings following disturbance. Establishment patterns between a hypothetical clearcut, strip-cut, and residual tree islands cut were simulated and compared. Distance from the seed source was identified as a major limitation to adequate stocking levels in the clearcut. The residual islands cut provided the highest stocking levels, followed by the strip-cut and clearcut. The results suggest large clearcuts are not an efficient harvesting method in interior Alaska for successful natural regeneration and stocking levels. The model results warrant further development and identified a "real" potential use as a forest management tool.
    • Bounty in the Bering Strait: a case for proactive regulation in the world's next chokepoint

      Russell, Emily Clarke; Ehrlander, Mary; Cole, Terrence; Meek, Chanda (2015-08)
      This thesis analyzes trends in waterborne trade throughout history to demonstrate that the Bering Strait will soon become a chokepoint of international trade. Scientific studies suggest that the accelerating effects of global warming in the Arctic will result in ice-free routes in the coming decades. Given the likelihood that vessel traffic through the Bering Strait will rise, this thesis assesses the region's ecological vulnerability, along with its significant commercial and cultural values. The history of shipping regulation worldwide and commercial regulation in the Bering Sea reveals a tendency to enact regulation in response to a major oil spill or species depletion. To ensure the food security of Native coastal communities and the productivity of commercial fisheries in the Bering Sea, this thesis argues for a proactive approach to vessel traffic regulation in the Bering Strait. It examines several current regulatory regimes to identify which could be enacted to protect the region's resources. This thesis concludes that, despite barriers to cooperation between Russia and the U.S., a cross-border management regime that promotes safe shipping through the Bering Strait would further both nations' economic interests and safeguard the Bering Sea's valuable yet vulnerable marine resources.
    • Breaking ground

      Peters, Kevin C. (2005-12)
      'Breaking Ground' is a collection of poems that follows a narrative arc as the speaker transitions from youth to adulthood. Set in the farmlands of Wisconsin, the manuscript examines numerous relationships: between men and women, children and parents, people and the land, and native and non-native inhabitants of the land. The manuscript addresses the idea of displacement: what it means to belong somewhere, to call someplace home, and what results when that home must be left behind or returned to. This idea is examined through poems about native culture, poems about divorce and the dissolution of a family, as well as poems about how a father dealt with the trauma of returning from Vietnam. Overall, the manuscript is a story of both a family and a region, and how those apparently separate entities-people and place-are intrinsically linked.
    • A breccia-centered ore and alteration model for the Copper Canyon alkalic Cu-Au porphyry deposit, British Columbia

      Twelker, Evan (2007-08)
      Similar to the nearby Galore Creek deposit, the Copper Canyon prospect of northwestern British Columbia is a porphyry-type copper-gold-silver occurrence associated with alkalic intrusive rocks of the Late Triassic-Early Jurassic Copper Mountain Suite. A reevaluation of the prospect geology shows that, of the previously recognized orthoclase and/or pseudoleucite porphyry syenite intrusions, mineralization is spatially and temporally associated with a single intrusive phase (unit i5) and biotite-garnet stockworks. Further, a newly defined unit of pre-mineralization magmatic-hydrothermal intrusive breccia occupies the core of the prospect and is a favorable host for much of the prospect mineralization. Prospect alteration can be divided into two distinct styles. Calc-potassic alteration consists of K-feldspar, Mg and Fe³-rich (An₂₀) biotite, andradite-rich garnet, hematite, magnetite, chalcopyrite, pyrite, and sphalerite (Zn₉₄₋₉₉, Fe₀.₅₋₂, Cd₀.₄₋₁)S and is associated with copper-gold-silver mineralization. Ankerite-sericite-pyrite (± fluorite, albite, anhydrite, pyrite, and trace covellite and bornite) alteration adjoins this core, hosting gold mineralization and insignificant copper. Sulfide-electrum and biotite geothermometry suggest fluid temperatures decreasing from the core (<̲S 550°C) to distal gold mineralization (<̲361°C). Distal gold mineralization is most likely the result of higher than typical sulfur activity and bisulfide transport of gold.
    • Breeding ecology and fasting tolerance of scaup and other ducks in the boreal forest of Alaska

      Martin, Kate H. (2007-08)
      Information on the breeding ecology of boreal forest ducks is lacking, despite management concern for species such as the lesser scaup (Aythya affinis), whose population has declined markedly since the 1980s. The mechanisms impacting population growth of scaup, and which component of their population dynamics is most affected, are unknown. Previous investigators hypothesized that food deprivation in the spring may reduce breeding success. My objectives were to: 1) examine reproductive parameters of lesser scaup and other ducks on the Yukon Flats in interior Alaska, and 2) measure the tolerance of captive scaup to fasting, in comparison to sympatric Northern shovelers (Anas clypeata) and American wigeon (Anas americana). Although breeding probability of paired females was assumed to be 1.0, the breeding probability of paired female scaup was between 0.12 (SE = 0.05, n=67) to 0.68 (SE = 0.08, n=37), and was positively related to body mass. These results suggest that managers may overestimate the productivity of boreal ducks using traditional survey methods. In addition, captive female scaup completely recovered from a loss of 11% body mass in only four days, suggesting that mass loss can be rapidly reversed, and may be able to obtain the body condition required for reproduction, if food supplies are adequate.
    • Breeding ecology of Smith's longspurs (Calcarius pictus) in the Brooks Range, Alaska

      Craig, Heather Rebekah; Powell, Abby; Kendall, Steve; O'Brien, Diane (2015-08)
      Alaska's Arctic ecosystem provides critical habitat for nesting songbirds. However, within this region climate change projections indicate a shrubbier future, as well as major shifts in summer weather patterns. The polygynandrous Smith's Longspur (Calcarius pictus) is a little known species that is closely tied to treeless tundra habitat in northern Alaska. I evaluated Smith's Longspur dispersal ability and annual survival rates using seven years of banding data, as well as breeding habitat requirements and reproductive success in two populations in the Brooks Range. Most adults (88%; n = 34) returned to nest in the same breeding neighborhood as previous years, and dispersal distance (x ± SE = 301 ± 70 m) did not differ between sexes. Only 4% of juvenile birds were resighted as adults and dispersal distance (x = 1674 ± 500 m; n = 6) was significantly greater for juveniles than for adults. From 674 capture-recapture histories, I evaluated annual survival and found that adult female survival (50-58%) was only slightly lower than for males (60-63%); juvenile survival was 41%, but was also paired with a low (13%) encounter probability. I examined nest-site selection patterns by comparing habitat measurements from 86 nests to paired random points within the nest area. Nests were typically found in open low shrub tundra and never among tall shrubs (height of tallest shrub x = 26.8 ± 6.7 cm). However, the only predictor of nest location I found was variation in willow height, which was slightly lower at nests than at random points. Daily nest survival rates were estimated from 257 nests and found to be relatively high (0.97-0.99) and consistent across years, and the best approximating model indicated that nest survival was negatively related to the numbers of days below freezing and season date. Despite dispersal ability and resilience to harsh conditions, Smith's Longspurs' response to climate change is unknown. The lack of sex-bias in dispersal and the low sex bias in survival, as well as the weak nest-site selection, may be attributed to the species' social mating system. Unlike most songbirds, multiple inter-mated individuals exist within each breeding neighborhood, altering social dynamics and likely demographic patterns. This is the first study to investigate the breeding biology of Smith's Longspurs at the western extent of their range and provides important conservation information as Arctic regions change.
    • Breeding ecology of whimbrels (Numenius phaeopus) in Interior Alaska

      Harwood, Christopher M.; Powell, Abby N.; Verbyla, David; Gill, Robert E. Jr. (2016-12)
      Whimbrels Numenius phaeopus breed in tundra-like habitats, both beyond treeline and within the boreal forest of interior Alaska. Despite their widespread distribution and designation as a species of conservation concern, their ecology has been particularly understudied in Alaska. During 2008--2012, I initiated the first dedicated study of Whimbrel breeding ecology in Alaska, and the first such study of any boreal-breeding shorebird in the state. Within a habitat mosaic of forest, woodlands, muskeg, scrub, and ponds within the floodplain of the Kanuti River in north-central Alaska, Whimbrels bred in the three largest (of nine) patches of discontinuous tussock tundra. These Whimbrels exhibited a compressed annual breeding schedule with the first birds arriving about 6 May and nests hatching about 17 June. Evidence for clustered and synchronous nesting, which may aid in predator defense, was equivocal. Most (69%) Whimbrels nested in mixed shrub-sedge tussock bog. I modeled nest-site selection at multiple spatial scales for 39 nests; however, the only variables important in the models were at the finest scale around the nest, namely that nests tended to be located on hummocks and exhibited lateral cover. Model results for nest survival of 67 nests over 4 years revealed a considerable difference in nest success (92% vs. 41%) at the two largest patches studied; this site effect was largely unexplained. To investigate Whimbrel ecology more broadly in the boreal biome, in 2013 I designed and conducted a Whimbrel-specific survey comprising 279 point counts within 28 transects along the road system of interior Alaska. I detected Whimbrels on just 32% of transects and 11% of count points. Although I detected Whimbrels at 3 sites where they had not been reported previously, I failed to detect them at several historically occupied sites. Dwarf shrub meadow was the most commonly observed habitat for all points visited. I modeled Whimbrel presence based on coarse habitat and avifaunal community features; no models were well supported. Between the local and regional surveys, my results tended to reinforce several widespread, but not necessarily investigated, descriptions about the breeding ecology of Whimbrels. My studies supported the premises that Whimbrels are patchily distributed on the landscape and often breed in clusters. Breeding of individuals and occupancy of some patches may be annually variable. Despite analyses of multiple habitat features at multiple spatial scales, I mostly observed a lack of specificity in where they bred among tundra-like patches, and where they nested specifically within such patches. This suggests that Whimbrels are tundra habitat generalists on their breeding grounds. Such phenotypic plasticity may be particularly adaptive in the dynamic, wildfire-prone landscape of interior Alaska.
    • Breeding ecology of white-winged scoters on the Yukon Flats, Alaska

      Safine, David Elliot (2005-08)
      Breeding bird surveys indicate a long-term decline in the numbers of scoters (Melanitta sp.) in North America. My objectives were to estimate survival of nests, ducklings, and adult female White-winged Scoters (Melanitta fusca) breeding on the Yukon Flats National Wildlife Refuge, Alaska, 2002-2004, within their primary breeding range. I measured habitat variables at nest sites and random sites in the study area to characterize nest habitat selection, and investigated breeding incidence with a laboratory analysis of circulating concentrations of the plasma yolk precursors vitellogenin (VTG) and very-low density lipoprotein (VLDL). The low hen and nest survival rates I observed combined with the substantial proportion of non-breeders on the breeding ground (up to 28%) may be responsible for the observed declines in abundance if annual survival rates are not high enough to maintain stable populations. Scoters avoided nesting in graminoid habitat, but nested in all other scrub or forested plant communities in proportion to their availability, selecting sites with more cover, higher variability of cover, and closer to edge and water than random sites. At the nest habitat scale, scoters are generalists, which may reduce the foraging efficiency of nest predators.
    • Breeding performance of kittiwakes and murres in relation to oceanographic and meteorologic conditions across the shelf of the southeastern Bering Sea

      Lloyd, Denby S. (1985-12)
      Contrary to expected results, black-legged and red-legged kittiwakes on St. George Island exhibited more variability in annual breeding performance than black-legged kittiwakes at Cape Peirce. Thick-billed and common murres at St. George also showed more annual variability than common murres at Cape Peirce. Kittiwakes at St. George exhibited improved breeding performance during years with colder water temperatures and lower summer wind speeds. Correlations between breeding performance in kittiwakes and murres and environmental conditions at Cape Peirce were inconclusive. A general decline in the annual breeding success of kittiwakes and murres at St. George between 1976 and 1984 coincided with reduced abundance of juvenile walleye pollock. Consistently low breeding success of kittiwakes and murres at Cape Peirce varied little among six years observed between 1970 and 1984. These results challenge previous considerations of pelagic food webs on the outer shelf as being more stable than those in the coastal domain.