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Colony-wide boat-based censuses suggest that numbers of Common Guillemots at Bluff, Alaska declined markedly in the late 1970s and remained low until 1983. Annual land-based counts of study plots since 1979 generally showed no trend. However, numbers declined substantially in one study area between 1978 and 1983. Reproductive success varied considerably among years and was highest in moderately warm summers. Simulation analyses suggest that the changes in numbers cannot be attributed to changes in reproductive success several years previously. Thus, factors affecting survival, presumably in winter, are apparently implicated in the declines.

The Seabird Tissue Archival and Monitoring Project (STAMP) is a collaborative Alaska-wide effort by the US Fish and Wildlife Service's Alaska Maritime National Wildlife Refuge (USFWS/AMNWR), the US Geological Survey's Biological Resources Division (USGS/BRD), the Bureau of Indian Affairs Alaska Region Subsistence Branch (BIA/ARSB), and the National Institute of Standards and Technology (NIST) to monitor long-term (decadal) trends in environmental contaminants using seabird eggs. To support this effort, a matrix- (seabird egg) and concentration-specific control material was needed to ensure quality during analytical work. Although a herring gull egg quality assurance (HGQA) material is available from Environment Canada (EC), contaminant concentrations in this material tended to be higher than those observed in Alaskan murre (Uria spp.) eggs. Therefore, to prepare a more appropriate control material, a total of 12 common murre (U. aalge) and thick-billed murre (U. lomvia) eggs from four Bering Sea and Gulf of Alaska nesting locations were cryohomogenized to create 190 aliquots each containing approximately 6 g. This new control material was analyzed by different methods at NIST and EC facilities for the determination of concentrations and value assignment of 63 polychlorinated biphenyl (PCB) congeners, 20 organochlorine pesticides, and 11 polybrominated diphenyl ether (PBDE) congeners. The total PCB concentration is approximately 58 ng g(-1) wet mass. Results obtained for analytes not listed on the certificates of analysis of the previously used control materials, HGQA and NIST's Standard Reference Material (SRM) 1946 Lake Superior Fish Tissue, are also presented.

Food availability comprises a complex interaction of factors that integrates abundance, taxonomic composition, accessibility, and quality of the prey base. The relationship between food availability and reproductive performance can be assessed via the nutritional stress (NSH) and junk- food (JFH) hypotheses. With respect to reproductive success, NSH posits that a deficiency in any of the aforementioned metrics can have a deleterious effect on a population via poor reproductive suc- cess. JFH, a component of NSH, posits specifically that it is a decline in the quality of food (i.e. energy density and lipid content) that leads to poor reproductive success. We assessed each in relation to reproductive success in a piscivorous seabird, the black-legged kittiwake Rissa tridactyla. We mea- sured productivity, taxonomic composition, frequency, size, and quality of meals delivered to nestlings from 1996 to 1999 at 6 colonies in Alaska, USA, 3 each in Prince William Sound and Lower Cook Inlet. Productivity varied widely among colony-years. Pacific herring Clupea pallasi, sand lance Ammodytes hexapterus, and capelin Mallotus villosus comprised ca. 80% of the diet among colony- years, and each was characterized by relatively high energy density. Diet quality for kittiwakes in this region therefore remained uniformly high during this study. Meal delivery rate and meal size were quite variable among colony-years, however, and best explained the variability in productivity. Par- ent kittiwakes appeared to select prey that were energy dense and that maximized the biomass pro- visioned to broods. While these results fail to support JFH, they do provide substantial support for NSH.

Sixty common murre (Uria aalge) and 27 thick-billed murre (Uria lomvia) eggs collected by the Seabird Tissue Archival and Monitoring Project (STAMP) in 1999-2001 from two Gulf of Alaska and three Bering Sea nesting colonies were analyzed for total mercury (Hg) using isotope dilution cold vapor inductively coupled mass spectrometry. Hg concentrations (wet mass) ranged from 0.011 microg/g to 0.357 microg/g (relative standard deviation = 76%), while conspecifics from the same colonies and years had an average relative standard deviation of 33%. Hg levels in eggs from the Gulf of Alaska (0.166 microg/g +/- 0.011 microg/g) were significantly higher (p0.0001) than in the Bering Sea (0.047 microg/g +/- 0.004 microg/g). Within the Bering Sea, Hg was significantly higher (p = 0.0007) in eggs from Little Diomede Island near the arctic than at the two more southern colonies. Although thick-billed and common murres are ecologicallysimilar,there were significant species differences in egg Hg concentrations within each region (p0.0001). In the Bering Sea, eggs from thick-billed murres had higher Hg concentrations than eggs from common murres, while in the Gulf of Alaska, common murre eggs had higher concentrations than those of thick-billed murres. A separate one-way analysis of variance on the only time-trend data currently available for a colony (St. Lazaria Island in the Gulf of Alaska) found significantly lower Hg concentrations in common murre eggs collected in 2001 compared to 1999 (p = 0.017). Results from this study indicate that murre eggs may be effective monitoring units for detecting geographic, species, and temporal patterns of Hg contamination in marine food webs. The relatively small intracolony variation in egg Hg levels and the ability to consistently obtain adequate sample sizes both within and among colonies over a large geographic range means that monitoring efforts using murre eggs will have suitable statistical power for detecting environmental patterns of Hg contamination. The potential influences of trophic effects, physical transport patterns, and biogeochemical processes on these monitoring efforts are discussed, and future plans to investigate the sources of the observed variability are presented.

cited By 17; International audience; Elevated mercury concentrations ([Hg]) were found in Alaskan murre (Uria spp.) eggs from the coastal embayment of Norton Sound relative to insular colonies in the northern Bering Sea-Bering Strait region. Stable isotopes of Hg, carbon, and nitrogen were measured in the eggs to investigate the source of this enrichment. Lower δ13C values in Norton Sound eggs (-23.3‰ to -20.0‰) relative to eggs from more oceanic colonies (-20.9‰ to -18.7‰) indicated that a significant terrestrial carbon source was associated with the elevated [Hg] in Norton Sound, implicating the Yukon River and smaller Seward Peninsula watersheds as the likely Hg source. The increasing [Hg] gradient extending inshore was accompanied by strong decreasing gradients of δ202Hg and Δ199Hg in eggs, indicating lower degrees of mass-dependent (MDF) and mass-independent Hg fractionation (MIF) (respectively) in the Norton Sound food web. Negative or zero MDF and MIF signatures are typical of geological Hg sources, which suggests murres in Norton Sound integrated Hg from a more recent geological origin that has experienced a relatively limited extent of aquatic fractionation relative to more oceanic colonies. The association of low δ202Hg and Δ199Hg with elevated [Hg] and terrestrial δ13C values suggested that Hg stable isotopes in murre eggs effectively differentiated terrestrial/geogenic Hg sources from oceanic reservoirs. © 2012 American Chemical Society.

The contents from thick-billed murre (Uria lomvia) eggs collected at four Alaskan colonies in 2002 were analyzed for organic contaminants and carbon δ¹³C) and nitrogen (δ¹⁵N) stable isotopes. Contaminant concentrations in the eggs varied from below detection limits to 230 ng g⁻¹ wet mass for 4,4'-DDE in one egg from St Lazaria Island in the Gulf of Alaska. Eggs from this colony generally contained higher levels of contaminants and exhibited significantly different patterns compared to eggs from the Bering and Chukchi seas. Stable isotope values also varied geographically; however, these differences appeared to be related to differences in C and N baselines in the food webs instead of differences in prey. Contaminant and stable isotope correlations were inconclusive, suggesting that better information on regional food web differences and differential offloading of contaminants and stable isotopes to the eggs must be obtained before these kinds of data can be fully incorporated into seabird egg contaminant monitoring programs.

Atmospheric deposition of mercury to remote areas has increased threefold since pre-industrial times. Mercury deposition is particularly pronounced in the Arctic. Following deposition to surface oceans and sea ice, mercury can be converted into methylmercury, a biologically accessible form of the toxin, which biomagnifies along the marine food chain. Mass-independent fractionation of mercury isotopes accompanies the photochemical breakdown of methylmercury to less bioavailable forms in surface waters. Here we examine the isotopic composition of mercury in seabird eggs collected from colonies in the North Pacific Ocean, the Bering Sea and the western Arctic Ocean, to determine geographical variations in methylmercury breakdown at northern latitudes. We find evidence for mass-independent fractionation of mercury isotopes. The degree of mass-independent fractionation declines with latitude. Foraging behaviour and geographic variations in mercury sources and solar radiation fluxes were unable to explain the latitudinal gradient. However, mass-independent fractionation was negatively correlated with sea-ice cover. We conclude that sea-ice cover impedes the photochemical breakdown of methylmercury in surface waters, and suggest that further loss of Arctic sea ice this century will accelerate sunlight-induced breakdown of methylmercury in northern surface waters. Atmospheric deposition of mercury to remote areas has increased threefold since pre-industrial times. Reductions in sea-ice cover accelerate the photodegradation of biologically accessible mercury in Arctic waters, according to an analysis of the isotopic composition of bird eggs in northern latitudes.

Gull eggs have been used to monitor contaminants in many parts of the world. The Seabird Tissue Archival and Monitoring Project (STAMP) is a long-term program designed to track trends in pollutants in northern marine environments using seabird eggs. Glaucous and glaucous-winged gull ( Larus hyperboreus and Larus glaucescens ) eggs collected in 2005 from seven Alaskan colonies were analyzed for organic contaminants. Concentrations ranged from below detection limits to 322 ng g −1 wet mass in one egg for 4,4′-DDE and differed among the samples collected in the Gulf of Alaska and Bering and Chukchi Seas. Chick growth and survival rates may be affected by the contaminant levels found in the eggs, but the eggs should be safe for human consumption if they are eaten in small quantities. STAMP plans to continue collecting and banking gull eggs for future real-time and retrospective analyses.

Concentrations of persistent organic pollutants (POPs) in eggs of common and thick-billed murres (Uria aalge and U. lomvia) from five Alaskan nesting colonies were dominated by 4,4'-DDE, total polychlorinated biphenyls (totalPCBs; 46 congeners comprised mainly of PCB congeners 153, 118, 138, 99, and 151), hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), and chlordane compounds (totalCHL). Concentrations of 4,4'-DDE, cis-nonachlor, and heptachlor epoxide were lower than those reported for some of the same colonies in the 1970s, while HCB concentrations were similar. In general, significantly higher concentrations were found in eggs from Gulf of Alaska colonies compared to those from Bering Sea colonies except for HCB (higher in the Bering Sea) and beta-HCH (no significant difference between the two regions). Thick-billed murre eggs contained higher concentrations of 4,4'-DDE and totalPCBs, whereas common murre eggs had higher HCB concentrations. Possible factors contributing to the POPs patterns found in eggs from these murre colonies are discussed.

The contents from thick-billed murre (Uria lomvia) eggs collected at four Alaskan colonies in 2002 were analyzed for organic contaminants and carbon (δ13C) and nitrogen (δ15N) stable isotopes. Contaminant concentrations in the eggs varied from below detection limits to 230 ng g−1 wet mass for 4,4′-DDE in one egg from St Lazaria Island in the Gulf of Alaska. Eggs from this colony generally contained higher levels of contaminants and exhibited significantly different patterns compared to eggs from the Bering and Chukchi seas. Stable isotope values also varied geographically; however, these differences appeared to be related to differences in C and N baselines in the food webs instead of differences in prey. Contaminant and stable isotope correlations were inconclusive, suggesting that better information on regional food web differences and differential offloading of contaminants and stable isotopes to the eggs must be obtained before these kinds of data can be fully incorporated into seabird egg contaminant monitoring programs.

Two distinct environmental settings in the Bering Strait region of the northern Bering Sea lead to characteristic pathways of energy flow through primarily pelagic food webs to avian consumers. In Norton Sound, a large, shallow embayment on the northeastern coast, the physical environment is dominated by the discharge of the Yukon River and by a large seasonal temperature signal. Seabirds breeding at Bluff, the largest colony in Norton Sound, number in the order of 5 × 104 and require 1.2 × 106 g C d−1. Two piscivorous species constitute the bulk of all seabirds there and are supported by a pelagic food web typical of the coastal zone of the Bering and Chukchi seas. This food web also is present around St. Lawrence Island, on the northwestern shelf, and is important to at least one species of seabird there. In addition, and generally more important, St. Lawrence Island is in a biologically rich environment resulting from the northward flow of water that originates along the continental shelf break of the Bering Sea. This flow apparently accounts for the unexpected presence of oceanic zooplankton and a diversity of forage fishes on the shallow northern shelf that support an abundant and taxonomically rich avifauna. In comparison to Norton Sound, breeding seabirds on St. Lawrence Island number in the order of 2 × 106, with planktivores consuming about 8 × 106 g C d−1 and piscivores consuming about 16 × 106 g C d−1.

Walleye pollock Theragra chalcogramma are important prey of piscivorous seablrds at offshore breeding colonies in the southeastern Bering Sea. The reproductive success of kittiwakes Rissa spp. is related to the abundance of juvenile pollock. It is proposed that poor pollock recruitment in recent years, as determ~ned by fisheries surveys, led to persistent kittiwake breeding failures in 1981-84. Declines in numbers of k~ttiwakes and other piscivorous seabirds at 2 colonies also may be related to the decline in pollock abundance. In contrast, planktivorous seabirds, which possibly compete with juvenile pollock for zooplankton, particularly copepods, might benefit from a low abundance of pollock. A conceptual model of food limitation and trophic interactions at several levels in the offshore pelagic food web of the eastern Bering Sea can be developed by relating relations between seabirds and their prey to ( l ) the high grazing efficiency of the herbivorous zooplankton community, which is dominated by large calanoid copepods, (2) estimates of a high annual loss of copepods, presumably to vertebrates, and (3) regional carbon budgets. The possibility that populations of several species respond to changes in pollock abundance should be considered in management decisions for the commercial pollock fishery

Food habits of thick-billed murres (Uria lomvia), common murres (U. aalge), and black-legged kittiwakes (Rissa tridactyla) were examined at two breeding colonies in the eastern Chukchi Sea between 1976 and 1980. Cods (Gadidae), sculpins (Cottidae), sand lance (Ammodytes hexapterus), and capelin (Mallotus villosus) were the dominant (biomass) prey of thick-billed murres. Cods, sand lance, and capelin were the dominant prey of common murres and kittiwakes. Annual changes in the consumption of fishes by murres and kittiwakes suggest that available fish biomass in the eastern Chukchi Sea was low in 1976 and 1977, but increased each year through 1979 and 1980. The average size of several taxa of fishes eaten by the birds increased also between most years. Invertebrates were less important than fishes in all years, were eaten most frequently by thick-billed murres, and were eaten more frequently in 1976–77 than in 1978–79. A pattern of climatic cooling in the early 1970's followed by warming in the second half of the decade caused annual differences in the extent and duration of sea ice, and apparently in the spacial and temporal development of Alaskan Coastal Water, a major oceanographic feature of the Bering–Chukchi shelf. Fluctuations in the physical environment could have led to changes in fish populations through direct physiological and behavioral effects, or indirectly by altering the abundance of important zooplankton prey populations. Variability in the reproductive success of murres and kittiwakes in the northern Bering Sea and eastern Chukchi Sea corresponded with the apparent changes in fish stocks: reproductive success was very low in 1976 but improved in successive years. Short-term responses of seabirds to environmental fluctuation and its proposed effect on supporting food webs suggest that the stability of regional seabird populations could also be affected by long-term changes in weather and climate.

During the course of a biosystematic study of the Peregrine Falcon (Falco peregrinus) by White over the past few years, observations have been made on several species of North American falcons. While all three large species (Prairie Falcon, Falco mexicanus; Gyrfalcon, Falco rusticolus; and Peregrine) have been subjected to detailed study by various writers, a few additional notes on their biology are reported herein. We would like to acknowledge the help in the field of William Tilton, Anchorage, Alaska, and the late Gary D. Lloyd of the University of Utah for stimulating discussions of the data presented. Marvin R. Meyer, of Salt Lake City, provided some data on Prairie Falcons.

Eggshell thickness after exposure to DDT was reduced by 21.7 percent in Alaskan tundra peregrines, by 16.8 percent in taiga peregrines, by 7.5 percent in Aleutian peregrines, by 3.3 percent in rough-legged hawks, and not at all in gyrfalcons. Tundra peregrine eggs contain an average of 889 parts of DDE per million (lipid basis); taiga peregrine eggs contain 673 parts per million; Aleutian peregrine eggs contain 167 parts per million; rough-legged hawk eggs contain 22.5 parts per million; and gyrfalcon eggs contain 3.88 parts per million. These changes in eggshell thickness and the pesticide residues reflect different degrees of exposure to contamination. There is a highly significant negative correlation between shell thickness and DDE content in peregrine eggs. Tundra and taiga peregrines have fledged progressively fewer young each year since 1966.

The 14 nesting records of the Kittlitz's Murrelet (Brachyramphus brevirostris) in Alaska were summarized by Day, Oakley, and Barnard (Condor 85:265-273, 1983). Here we give the details of a nest record that they reported as the "Chukchi Sea" record. On 28 June 1978, two geologists, P. Metz and M. Robinson of Fairbanks, discovered the nest of an unidentified bird in the De Long Mountains (68*04'20"N, 162050'00"W, see Fig. 1). We visited the site on 29 June 1978 and identified the adult as a Kittlitz's Murrelet (Fig. 2). The murrelet did not flush until we were within a few meters of the nest-site. It had been incubating a single egg that measured 39 x 58 mm. We departed several minutes later, and the adult returned to the nest as we withdrew. The nest-site was located about 300 m above sea-level on a north-facing barite talus slope, devoid of vegetative cover. The nest was simply a slight, relatively flat depression in the talus slope (see Fig. 2). Linear distance to the nearest stream was 200-250 m. The nest-site was 75 km (straight-line distance) from the coast, indicating a minimum round-trip distance of 150 km to foraging areas for adults. This nest-site is considerably farther inland than others previously reported (ranging from 0.25 km to 30