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King Eider (Somateria spectabilis) historical records indicate it is rare in the lower Chesapeake Bay, casual in open water of major tributaries, while not occurring in upper tributary portions. This study reviews various collection inventory databases and publications ranging 1866-2020 to compile, for evaluation, King Eider occurrence records in Chesapeake Bay. Records suitable for analysis total 90 of which 81% fall in the period 9 November-3 March, and 79% involve a single eider. Locations in the lower third of Chesapeake Bay (south of Tangier Island) comprise 53% of the occurrence records. National Audubon Society, Christmas Bird Counts constitute 31% of the records. The records providing age during the November-March period give 10% as immature plumage and 8% as adult, while records providing sex give 21% as female and 13% as male. The warm-weather records (20 May-3 October) providing age denote 12% as immature plumage and 3% as adult while records providing sex show 6% female. Single eider constitute all except one of the 17 warm-weather records with most exhibiting immature plumage being found at the same location for four consecutive weeks or more while appearing to be flightless. Detection and identification of immature or female plumage (juvenile, sub-adult) King Eider may be difficult and present uncertainties especially when viewing at a distance, under poor light or spray conditions, rough seas, or mixing with similar appearing scoter species. King Eider occurrence in Chesapeake Bay may be more frequent than records indicate considering the number of incidences found despite their rare and casual classifications, plus identification difficulties with female and/or immature plumages. [ABSTRACT FROM AUTHOR]

The molting and wintering areas of the western King eider population (Somateria spectabilis) in the Barents, White, and Kara seas are described based on our own observations and relevant reports in the literature; schematic maps show bird gathering areas in these periods. The data on counts of wintering and molting birds, their age, and sex composition in the Russian part of the distribution range are provided. Six to ten thousand birds of this species wintered on the White Sea and in the southern part of the Barents Sea in 1994–2009. In the winter of 2009, males were obviously predominant (70.2%); immature individuals accounted for 2.6%. The highest concentrations of King eiders were recorded in the southeastern part of the Barents Sea during molting. The total number of molting King eiders in this area was 18 000 to 20 000 individuals. We estimated the total size of the western King eider population in the Barents Sea region. Discarding the birds that winter near the coasts of Novaya Zemlya, this indicator may range from 80 000 to 110 000 individuals. Factors that influence the distribution of birds during particular seasons and their movements within the range are shown. To further advance King eider monitoring, we suggest suitable parts of water areas and adequate approaches to bird counting. [ABSTRACT FROM AUTHOR]

The South-west Greenland Open Water Area is an internationally important wintering area for seabirds in the North Atlantic. Nearly two decades after the area was last surveyed, we conducted a replicate aerial survey in March 2017 to update information on the distribution and abundance of seabirds. With a total effort of about 5800 km, we covered the coastal area from Aasiaat (69°N) to Kap Farvel (60°N), 56% of the open water area in the fjords, and the offshore bank, Store Hellefiskebanke. Line transect survey methodology was used except in the fjords, which were censused by total counts. By means of distance sampling analyses, the abundances of the dominant species were estimated to be roughly 1100 000 king eiders (Somateria spectabilis), 443 000 common eiders (Somateria mollissima), 42 000 long-tailed ducks (Clangula hyemalis) and 76 000 Iceland gulls/glaucous gulls (Larus glaucoides/Larus hyperboreus). For the great black-backed gull (Larus marinus), great cormorant (Phalacrocorax carbo), mallard (Anas platyrhynchos) and red-breasted merganser (Mergus serrator), we present the first winter population estimates for the area (6100, 7700, 7600 and 3200 individuals, respectively). Areas around Kangaatsiaq, Nuuk and Julianehåbsbugten were identified as key wintering sites, as was Store Hellefiskebanke which held 99% of the king eiders. For all species assessed in 1999, abundance in the coastal survey area was considerably lower in 2017. In some cases, this may be due to changes in distribution patterns. However, for thick-billed murre (Uria lomvia), long-tailed duck and black-legged kittiwake (Rissa tridactyla), the reduced coastal abundances coincide with declining breeding populations.

The South-west Greenland Open Water Area is an internationally important wintering area for seabirds in the North Atlantic. Nearly two decades after the area was last surveyed, we conducted a replicate aerial survey in March 2017 to update information on the distribution and abundance of seabirds. With a total effort of about 5800 km, we covered the coastal area from Aasiaat (69°N) to Kap Farvel (60°N), 56% of the open water area in the fjords, and the offshore bank, Store Hellefiskebanke. Line transect survey methodology was used except in the fjords, which were censused by total counts. By means of distance sampling analyses, the abundances of the dominant species were estimated to be roughly 1100 000 king eiders (Somateria spectabilis), 443 000 common eiders (Somateria mollissima), 42 000 long-tailed ducks (Clangula hyemalis) and 76 000 Iceland gulls/glaucous gulls (Larus glaucoides/Larus hyperboreus). For the great black-backed gull (Larus marinus), great cormorant (Phalacrocorax carbo), mallard (Anas platyrhynchos) and red-breasted merganser (Mergus serrator), we present the first winter population estimates for the area (6100, 7700, 7600 and 3200 individuals, respectively). Areas around Kangaatsiaq, Nuuk and Julianehåbsbugten were identified as key wintering sites, as was Store Hellefiskebanke which held 99% of the king eiders. For all species assessed in 1999, abundance in the coastal survey area was considerably lower in 2017. In some cases, this may be due to changes in distribution patterns. However, for thick-billed murre (Uria lomvia), long-tailed duck and black-legged kittiwake (Rissa tridactyla), the reduced coastal abundances coincide with declining breeding populations. [ABSTRACT FROM AUTHOR]

Four species of threatened or declining eider ducks that nest in the Arctic migrate through the northeast Chukchi Sea, where anticipated industrial development may require prioritizing areas for conservation. In this nearshore corridor (10–40 m depth), the eiders’ access to benthic prey during the spring is restricted to variable areas of open water within sea ice. For the most abundant species, the king eider ( Somateria spectabilis ), stable isotopes in blood cells, muscle, and potential prey indicate that these eiders ate mainly bivalves when traversing this corridor. Bivalves there were much smaller than the same taxa in deeper areas of the northern Bering Sea, possibly due to higher mortality rates caused by ice scour in shallow water; future decrease in seasonal duration of fast ice may increase this effect. Computer simulations suggested that if these eiders forage for >15 h/day, they can feed profitably at bivalve densities >200 m −2 regardless of water depth or availability of ice for resting. Sampling in 2010–2012 showed that large areas of profitable prey densities occurred only in certain locations throughout the migration corridor. Satellite data in April–May over 13 years (2001–2013) indicated that access to major feeding areas through sea ice in different segments of the corridor can vary from 0% to 100% between months and years. In a warming and increasingly variable climate, unpredictability of access may be enhanced by greater effects of shifting winds on unconsolidated ice. Our results indicate the importance of having a range of potential feeding areas throughout the migration corridor to ensure prey availability in all years. Spatial planning of nearshore industrial development in the Arctic, including commercial shipping, pipeline construction, and the risk of released oil, should consider these effects of high environmental variability on the adequacy of habitats targeted for conservation. [ABSTRACT FROM AUTHOR]

Post-fledging dispersal and site fidelity are poorly understood, particularly for sea ducks that spend the majority of their annual cycle at sea. This is the first description of movements and their timing for first-year (juvenile) and second-year (subadult) King Eiders Somateria spectabilis in relation to their attendant females. We fitted satellite transmitters that operated for 2 years to 63 hatch-year birds and 17 attendant females at breeding areas in northern Alaska in 2006-2009. Our goals were to describe the spatio-temporal distribution of pre-breeding individuals and adult females that had been successful breeders. We also examined fidelity to wing moulting and wintering areas as well as natal philopatry. Juveniles did not appear to follow attendant adults, although they did winter in the same three general wintering areas, suggesting that genetic inheritance and social factors may have roles in the initial migration from the breeding area. Additionally, juveniles were more variable in the timing and duration of migration, moved longer distances during the winter, and were less faithful to moulting and wintering areas than adults, indicating that individual exploration and acquired navigational memory played a role in subsequent migrations. Most (75%) subadult females returned to natal areas, probably prospecting for future nesting sites, whereas subadult males were widely dispersed at sea. Timing and duration of moult migration and wing moult of adult females that were presumed to be successful breeders differed from those of unsuccessful breeders due to the extended time that the former spent on the breeding grounds. Temporal and spatial segregation of post-fledging King Eiders from adults has direct management implications in terms of resource development and population dynamics. [ABSTRACT FROM AUTHOR]

In addition to estimating survival probability of adult birds, estimating recruitment of new individuals into avian breeding populations is fundamental to understanding rates of population change. Notions about mean recruitment age can lead to erroneous conclusions about population projections if the probability of capture is ignored. We calculated the mean recruitment age of King Eiders (Somateria spectabilis) using two methods: (1) a naive estimate based strictly on observed age at first recapture of marked ducklings as nesting females; and (2) reversed capture histories, which incorporate probability of capture into estimates. From 1996 to 2009, we marked 2,390 King Eider ducklings, 53 of which were recaptured from 2007 to 2010 as females nesting at Karrak Lake, Nunavut, in Canada's Central Arctic region. The naive approach estimated mean (± 95% CL) recruitment age as 4.58 ± 0.42 yr, whereas reversed capture histories estimated mean recruitment age as 4.08 ± 0.34 yr. We illustrate the influence of recruitment age (range: 3-9 yr) on the predicted annual rate of population change. We fit numerous ecological covariates to test for cohort effects, phenology of vernal thaw, absolute and relative nesting phenology of mothers, maternal body size, density dependence, and relative clutch size on age-specific recruitment probability. There was good support for a negative effect of relative initiation date of nests that produced ducklings, and equivocal support for an additive negative influence of vernal thaw at the age that ducklings were recruited as breeders. We discuss the implications of variation in female recruitment age for King Eider population biology and fitness. More broadly, we reiterate previous advice (e.g., Pradel et al. 1997, Schwarz and Arnason 2000), against calculation of mean recruitment age from age at first capture, regardless of study species, particularly when detection probability of recruits is low. [ABSTRACT FROM AUTHOR]

The North American population of king eiders ( Somateria spectabilis) has declined by more than 50% since the late 1970s for unknown reasons. King eiders spend most of their lives in remote areas, forcing managers to make regulatory and conservation decisions based on very little information. We incorporated available published estimates of vital rates with new estimates to build a female, stage-based matrix population model for king eiders and examine the processes underlying population dynamics of king eiders breeding at 2 sites, Teshekpuk and Kuparuk, on the coastal plain of northern Alaska and wintering around the Bering Sea (2001-2010). We predicted a decreasing population ( λ = 0.981, 95% CI: 0.978-0.985), and that population growth was most sensitive to changes in adult female survival (sensitivity = 0.92). Low duckling survival may be a bottleneck to productivity (variation in ducking survival accounted for 66% of retrospective variation in λ). Adult survival was high (0.94) and invariant ( ${\hat {\sigma }}^{2} $ = 0.0002, 95% CI: 0.0000-0.0007); however, catastrophic events could have a major impact and we need to consider how to mitigate and manage threats to adult survival. A hypothetical oil spill affecting breeding females in a primary spring staging area resulted in a severe population decline; although, transient population dynamics were relatively stable. However, if no catastrophic events occur, the more variable reproductive parameters (duckling and nest survival) may be more responsive to management actions. Published 2012. This article is a U.S. Government work and is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

The article focuses on the impact of Tropical Storm Irene and a major snowstorm on birding activities in Connecticut. In the 52nd Supplement of the American Ornithologists Union Checklist, one of the taxonomic changes adopted involves the order of the wood-warblers. Several birds sighted in Connecticut following the storm include Greater White-fronted geese, a male King Eider, and a Great Shearwater.

The National Museum at Prague possesses 45 skins of birds collected during the Herdemerten's Expedition to western Greenland in summer 1938, including those of Gyrfalcons caught for the purposes of falconry. These skins provide an additional insight into this less known expedition. [ABSTRACT FROM AUTHOR]

The article discusses the use of nape tags to mark the offspring of precocial birds which enabled the observation of the young's behavior, interactions and post-hatching survival. Included in the study are the chicks of the American coot and the ducklings of the Ruddy Duck, King Eider and the White-winged Scoter. The tags are affordable, offer a large number of unique color combinations and are visible with binoculars from as far as 150 meters. The only drawback is the 20% incidence of loss.

The number of common eiders ( Somateria mollissima borealis) in west Greenland declined dramatically during the twentieth century, supposedly because of human activities. However, their sensitivity to alternative drivers of variation, such as climate conditions, diseases or food availability, remains unstudied. In this study, we describe prey availability and assess the trophic coupling between eiders and their macrobenthic prey in a shallow inlet, Nipisat Sound; a key wintering habitat in the south-west Greenland Open Water Area. Macrobenthic species abundance and biomass were studied, and annual production was estimated by an empirical model, including environmental characteristics, fauna composition and individual biomass. In spring 2008, average macrozoobenthic abundance and biomass were 6,912 ind m and 28.4 g ash-free dry mass (AFDM) m (647 kJ m), respectively. Annual production was estimated at 13.9 g AFDM m year (317 kJ m year). During the winters of 2008-2010, we monitored the number of common eiders ( S. mollissima borealis) and king eiders ( Somateria spectabilis) and observed a distinct peak in abundance during winter with up to 15.000 birds in Nipisat Sound. Based on physiological costs of different activities in combination with the observed behavioural pattern, we obtained an estimate of the energy required for eiders to balance their costs of living, which amounted to 58% of the estimated total annual production of macrobenthos in Nipisat Sound. This result suggests that eider predation affects macrobenthic species composition and biomass and demonstrates the potential importance of variations in prey availability for the population dynamics of eiders in Greenland. [ABSTRACT FROM AUTHOR]

The article enumerates the bird sightings reported over the winter season from December 2010 to February 2011. Presented are details on the observer, the bird species, the number seen, date of discovery, duration of stay, events that transpired and other facts such as previous sightings of the same bird. Certain bird species were highlighted which include king eiders, the barnacle goose and the barrow's golden-eye.

The article presents a study that investigated the foraging effort of King Eider during its pre-breeding period in northern Alaska. It says that King Eider is a large sea duck that breeds in arctic tundra ecosystems worldwide and spends most of its time at sea. It mentions that many arctic-nesting migratory birds rely on nutrients present on the breeding grounds. It relates that the study was conducted near the southeast shore of Teshekpuk Lake on the coastal plain of Alaska.

The article provides a summary of reports on bird sightings in Great Britain from October to November 2010. The birds include the American Wigeon Anas americana Slimbridge in Gloucestershire, England, the King Eider Somateria spectabilis Burghead in Orkney, Scotland and the House Finch Carpodacus mexicanus East Prawle in Devon, England

The Norwegian coast is a very important winter area for king eiders ( Somateria spectabilis), but their origin has been unknown. We determined spring and autumn migration routes, timing of migration and potential breeding areas of king eiders wintering in north-eastern Norway using implanted satellite transmitters. Five males and five females were equipped with transmitters in February 2008, and location data were received from six birds. All birds departed within 10 days in mid April and flew to the Pechora Sea and Kara Sea in western Russia where they staged until mid June. Subsequently, four of five birds with active transmitters (two females and two males) moved east to potential breeding locations on the Gydan and Taymyr Peninsulas. In early July, the males moved west to moult at Kolguyev Island and in the Pechora Sea. The two females departed in mid July, one probably moulting between the gulfs of the Ob and Yenisei Rivers, after which it moved to the Pechora Sea. The other female probably moulted in the eastern Taymyr, thereafter moving to Novaya Zemlya. This female returned to the north-eastern coast of Norway 1 December, while the other female returned 2 January. For the males, the transmitters stopped in December/January when they were still in the Pechora/Kolguyev area. King eiders wintering in north-eastern Norway thus originate from the western half of Arctic Russia, and the Taymyr Peninsula is probably the dividing point between the eastern and western flyways. [ABSTRACT FROM AUTHOR]

The use of stored nutrients for reproduction represents an important component of life-history variation. Recent studies from several species have used stable isotopes to estimate the reliance on stored body reserves in reproduction. Such approaches rely on population-level dietary endpoints to characterize stored reserves (“capital”) and current diet (“income”). Individual variation in diet choice has so far not been incorporated in such approaches, but is crucial for assessing variation in nutrient allocation strategies. We investigated nutrient allocation to egg production in a large-bodied sea duck in northern Alaska, the king eider ( Somateria spectabilis). We first used Bayesian isotopic mixing models to quantify at the population level the amount of endogenous carbon and nitrogen invested into egg proteins based on carbon and nitrogen isotope ratios. We then defined the isotopic signature of the current diet of every nesting female based on isotope ratios of eggshell membranes, because diets varied isotopically among individual king eiders on breeding grounds. We used these individual-based dietary isotope signals to characterize nutrient allocation for each female in the study population. At the population level, the Bayesian and the individual-based approaches yielded identical results, and showed that king eiders used an income strategy for the synthesis of egg proteins. The majority of the carbon and nitrogen in albumen (C: 86 ± 18%, N: 99 ± 1%) and the nitrogen in lipid-free yolk (90 ± 15%) were derived from food consumed on breeding grounds. Carbon in lipid-free yolk derived evenly from endogenous sources and current diet (exogenous C: 54 ± 24%), but source contribution was highly variable among individual females. These results suggest that even large-bodied birds traditionally viewed as capital breeders use exogenous nutrients for reproduction. We recommend that investigations of nutrient allocation should incorporate individual variation into mixing models to reveal intraspecific variation in reproductive strategies. [ABSTRACT FROM AUTHOR]

Incubating birds balance their energetic demands during incubation with the needs of the developing embryos. Incubation behavior is correlated with body size; larger birds can accumulate more endogenous reserves and maintain higher incubation constancy. King eiders ( Somateria spectabilis) contend with variable and cold spring weather, little nesting cover, and low food availability, and thus are likely to rely heavily on endogenous reserves to maintain high incubation constancy. We examined the patterns of nest attendance of king eiders at Teshekpuk and Kuparuk, Alaska (2002–2005) in relation to clutch size, daily temperature, and endogenous reserves to explore factors controlling incubation behavior. Females at Kuparuk had higher constancy (98.5 ± 0.2%, n = 30) than at Teshekpuk (96.9 ± 0.8%, n = 26), largely due to length of recesses. Mean recess length ranged from 21.5 to 23.7 min at Kuparuk, and from 28.5 to 51.2 min at Teshekpuk. Mean body mass on arrival at breeding grounds (range; Teshekpuk 1,541–1,805, Kuparuk 1,616–1,760), and at the end of incubation (Teshekpuk 1,113–1,174, Kuparuk 1,173–1,183), did not vary between sites or among years ( F < 1.1, P > 0.3). Daily constancy increased 1% with every 5°C increase in minimum daily temperature ( βmin = 0.005, 95% CI 0.002, 0.009). Higher constancy combined with similar mass loss at Kuparuk implies that females there met foraging requirements with shorter recesses. Additionally, females took more recesses at low temperatures, suggesting increased maintenance needs which were potentially ameliorated by feeding during these recesses, indicating that metabolic costs and local foraging conditions drove incubation behavior. [ABSTRACT FROM AUTHOR]

The article discusses a study on the estimation of King Eider survival rates from satellite telemetry. It states that satellite transmitter were implanted to bird to assess whether a bird was alive or dead. It says that the study used estimators such as the Kaplan-Meier product-limit for monthly survival rate estimation. Results of the study showed that high natal philopatry in females suggests that high dispersal rates of males account for juvenile survival rates' sex-specific differences.

The article offers information on a number of birds that were sighted in Connecticut during the autumn of 2009. Five Greater White-fronted Geese were sighted on October 18 at the Mackenzie Reservoir of the University of Connecticut in Wallingford and in Newtown. Four Blue-winged Teal were spotted on August 7 at White Memorial Foundation's Cemetery Pond in Litchfield. A male King Eider was spotted at Hommonasset Beach State Park in Madison.

The article discusses a study on the impact of lipid extraction on stable isotope ratios in avian egg yolk. The procedure of the study started by collecting King Eider eggs in Alaska between 2006 and 2007. The laboratory techniques applied in the study include lyophilizing and homogenizing yolk samples. Steps to minimize analytical costs for species that likely derive lipids and proteins from the same source and environment are recommended.

Arrival time on breeding or non-breeding areas is of interest in many ecological studies exploring fitness consequences of migratory schedules. However, in most field studies, it is difficult to precisely assess arrival time of individuals. Here, we use carbon isotope turnover in avian blood as a technique to estimate arrival time for birds switching from one habitat or environment to another. Stable carbon isotope ratios (δ13C) in blood assimilate to a new equilibrium following a diet switch according to an exponential decay function. This relationship can be used to determine the time a diet switch occurred if δ13C of both the old and new diet are known. We used published data of captive birds to validate that this approach provides reliable estimates of the time since a diet switch within 1–3 weeks after the diet switch. We then explored the utility of this technique for King Eiders ( Somateria spectabilis) arriving on terrestrial breeding grounds after wintering and migration at sea. We estimated arrival time on breeding grounds in northern Alaska (95% CI) from red blood cell δ13C turnover to be 4–9 June. This estimate overlapped with arrival time of birds from the same study site tracked with satellite transmitters (5–12 June). Therefore, we conclude that this method provides a simple yet reliable way to assess arrival time of birds moving between isotopically distinct environments. [ABSTRACT FROM AUTHOR]

Somateria mollissima (Common Eider) is an important game species throughout its circumpolar range, including eastern Canada and northeastern United States. In eastern Canada, the largest harvest of Common Eiders occurs in Newfoundland; however, the age, sex, and subspecific composition (S. m. borealis and dresseri are both present) of this hunted population is not well quantified. The species, subspecies, age, and sex composition of the harvest was determined by examining heads collected from 1672 eiders (including Somateria spectabilis [King Eider]), taken mostly by hunters, from 1980-1996. Band-recovery information for Common Eiders banded in Newfoundland and Labrador were also summarized, including data from a release program of hand-reared ducklings in northern Newfoundland from 1988-1996. The composition of the eider harvest varied across the province. In northern and eastern areas, borealis Common Eiders made up the bulk of the harvest. King Eiders were also taken in these areas. In southern areas, most Common Eiders taken were dresseri. Sex ratios tend to be near 1:1, and immature birds comprised most of the harvest. Recovery distributions showed that Common Eiders breeding in Newfoundland and Labrador were mainly taken within the province, but also contributed to harvests in Quebec and Nova Scotia, and to a lesser extent, Maine. Hand-reared ducklings had direct recovery rates of 0.047 and were most likely to be recovered within the province in the year of banding, but contributed to harvests in Atlantic Canada and New England as they aged. The harvest of eiders in Newfoundland varies regionally and seasonally; therefore specific harvest regulations could be implemented to manage the variety of populations present in the province throughout the year. [ABSTRACT FROM AUTHOR]

Nest site selection is a critical component of reproduction and has presumably evolved in relation to predation, local resources, and microclimate. We investigated nest-site choice by king eiders (Somateria spectabilis) on the coastal plain of northern Alaska, USA, 2003-2005. We hypothesized that nest-site selection is driven by predator avoidance and that a variety of strategies including concealment, seclusion, and conspecific or inter-specific nest defense might lead to improved nesting success. We systematically searched wetland basins for king eider nests and measured habitat and social variables at nests (n=212) and random locations (n=493). King eiders made use of both secluded and concealed breeding strategies; logistic regression models revealed that females selected nests close to water, on islands, and in areas with high willow (Salix spp.) cover but did not select sites near conspecific or glaucous gull (Larus hyperboreus) nests. The most effective nest-placement strategy may vary depending on density and types of nest predators; seclusion is likely a mammalian-predator avoidance tactic whereas concealment may provide protection from avian predators. We recommend that managers in northern Alaska attempt to maintain wetland basins with islands and complex shorelines to provide potential nest sites in the vicinity of water. [ABSTRACT FROM AUTHOR]

Events during the non-breeding season may affect the body condition of migratory birds and influence performance during the following breeding season. Migratory birds nesting in the Arctic often rely on endogenous nutrients for reproductive efforts, and are thus potentially subject to such carry-over effects. We tested whether king eider ( Somateria spectabilis) arrival time and body mass upon arrival at breeding grounds in northern Alaska were affected by their choice of a winter region in the Bering Sea. We captured birds shortly after arrival on breeding grounds in early June 2002–2006 at two sites in northern Alaska and determined the region in which individuals wintered using satellite telemetry or stable isotope ratios of head feathers. We used generalized linear models to assess whether winter region explained variation in arrival body mass among individuals by accounting for sex, site, annual variation, and the date a bird was captured. We found no support for our hypothesis that either arrival time or arrival body mass of king eiders differed among winter regions. We conclude that wintering in different regions in the Bering Sea is unlikely to have reproductive consequences for king eiders in our study areas. [ABSTRACT FROM AUTHOR]

We examined King Eider (Somateria spectabilis) brood survival in the Kuparak oil field in northern Alaska in 2002 and 2003 by monitoring hens with broods using radiotelemetry. We observed complete brood loss in eight of 10 broods. Broods survived less than 2 weeks on average, and most mortality occurred within 10 days of hatch. Distance hens traveled overland did not affect brood survival. Apparent King Elder brood survival in our study area was lower than reported for eider species in other areas. We recommend future studies examine if higher densities of predators in oil fields reduces King Eider duckling survival. [ABSTRACT FROM AUTHOR]

1. Many migratory birds are assumed to remain fairly stationary during winter. However, recent research indicates that mid-winter movements are evident in a variety of bird species, and the factors causing individuals to move are poorly understood. 2. We examined the winter movements of 95 individual king eiders ( Somateria spectabilis, L.) tracked with satellite transmitters in the Bering Sea between 2002 and 2006 to explore whether environmental factors such as day length, location, sea ice, and habitat quality could explain the occurrence of winter movements longer than 50 km. 3. We used a novel algorithmic random forest model to assess the importance of variables predicting whether a bird remained or departed from a wintering site. 4. We found extremely high individual variability in winter movement decisions by king eiders, and the individual bird was the most important variable followed by location, date, and sea ice concentration. 5. We conclude that individual strategies exist that interact with environmental conditions to form multiple movement patterns. 6. While a minor proportion of winter movements may be forced by environmental conditions, we propose that many winter movements may be of an exploratory nature where individuals aim to acquire information about alternative wintering sites that may enhance their survival probability at some point in time when environmental fluctuation renders their preferred wintering site unsuitable. [ABSTRACT FROM AUTHOR]

The evaluation of habitats used by arctic birds on migration is crucial for their conservation. We explored the importance of the eastern Chukchi Sea (ECS) as a staging area for king eiders ( Somateria spectabilis) migrating between breeding areas in Siberia and western North America and wintering areas in the Bering Sea. We tracked 190 king eiders with satellite transmitters between 1997 and 2007. In late summer, 74% of satellite-tracked king eiders migrating south staged in the ECS for 13 ± 13 (SD) days between late June and early November. During spring migration, king eiders staged in the ECS between mid-April and early June for 21 ± 10 days. All instrumented birds migrating to breeding grounds in western North America ( n = 62), and 6 of 11 males migrating to breeding grounds in Siberia, used this area for at least 1 week during spring migration. The importance of this staging area renders it possible that industrial development could adversely affect king eider populations in both Siberia and North America. [ABSTRACT FROM AUTHOR]

In long-lived species, adult survival is the population parameter having the highest elasticity, and therefore, it can be expected to be least affected by climatic variations. We studied the dynamics and survival of breeding female common eiders Somateria mollissima mollissima in the Baltic Sea from 1960 to 2007. Using nest censuses and capture–recapture methods, we investigated: (1) the annual apparent survival (φ) of breeding females, (2) the survival-mediated population fluctuation, (3) weather effects on survival, and (4) long-term population trends. Based on capture histories of 6,393 females, average φ was 0.882 (95% confidence interval 0.864, 0.899). We found no relationship between population growth rate and survival. Furthermore, the highest ranking models, based on Akaike’s information criterion, indicated no effect of the North Atlantic Oscillation index on the φ of eider females. Population size, assessed from nest counts, has been steadily declining since 1985. Despite the long time series (48 years), the overall variation in the φ rates remained comparatively narrow, at maximum ranging only 10% between 2 consecutive years. Results imply that declining female survival is not the driving force behind the population decline, and we hypothesize that the overall poor fledging success and the consequent low recruitment explain the decreasing trend of nest densities since 1985. [ABSTRACT FROM AUTHOR]

Development of minimally invasive techniques to collect nutritional information from free-living birds is desirable for both ethical and conservation reasons. Here, we explore the utility of waterfowl eggshell membranes to determine the nutrient source of egg formation by using stable isotope ratios. We compared δ13C and δ15N of membranes from complete king eider ( Somateria spectabilis) eggs to membranes of hatched or depredated eggs of the same clutch remaining after incubation. Despite large variation among membranes (δ13C: −26 to −14‰) we found a highly predictable relationship between δ13C of complete egg membranes and remaining (hatched or depredated) membranes from the same clutch. We did not find a consistent change in either δ13C or δ15N of eggshell membranes during incubation. We suggest that isotope ratios of membranes can be used to determine the source of exogenous nutrients for egg production in income breeders, and that membranes may offer a clutch-specific reference point for dietary nutrients (‘income endpoint’) in isotopic mixing models quantifying nutrient allocation in capital or mixed-strategy breeders. [ABSTRACT FROM AUTHOR]

We measured plasma concentrations of variables associated with lipid metabolism (free fatty acids, glycerol, triglyceride, and β-hydroxybutyrate), protein metabolism (uric acid), and baseline corticosterone to characterize the nutritional state of incubating king eiders Somateria spectabilis and relate this to incubation constancy at two sites, Kuparuk and Teshekpuk, in northern Alaska. King eiders at both sites appeared to employ a partial-income incubation strategy, relying on both endogenous and exogenous energy resources. Females maintained high invariant levels of free fatty acids, β-hydroxybutyrate, and glycerol throughout incubation, indicating that fat reserves were a major energy source, and not completely depleted during incubation. Similarly, uric acid did not increase, suggesting effective protein sparing or protein ingestion and adequate lipid reserves throughout incubation. Baseline corticosterone and triglyceride levels increased during incubation, indicative of an increase in foraging during late stages of incubation. Incubating females at Kuparuk had higher triglyceride concentrations but also had higher β-hydroxybutyrate concentrations than females at Teshekpuk. This dichotomy may reflect a short-term signal of feeding overlaying the longer-term signal of reliance on endogenous lipid reserves due to higher food intake yet higher metabolic costs at Kuparuk because of its colder environment. Incubation constancy was not correlated with plasma concentrations of lipid or protein metabolites. [ABSTRACT FROM AUTHOR]

King eider (Somateria spectabilis) populations have declined markedly in recent decades for unknown reasons. Nest survival is one component of recruitment, and a female's chance of reproductive success increases with her ability to choose an appropriate nesting strategy. We estimated variation in daily nest survival of king eiders at 2 sites, Teshekpuk and Kuparuk, Alaska, USA, 2002-2005. We evaluated both a priori and exploratory competing models of nest survival that considered importance of nest concealment, seclusion, and incubation constancy as strategies to avoid 2 primary egg predators, avian (Larus spp., Stercorarius spp., and Corvus corax) and fox (Alopex lagopus). We used generalized nonlinear techniques to examine factors affecting nest survival rates and information-theoretic approaches to select among competing models. Estimated nest survival, accounting for a nest visitation effect, varied considerably across sites and years (0.21-0.57); however, given our small sample size, much of this variation may be attributable to sampling variation (σ²process = 0.007, 95% CI: 0.003-0.070). Nest survival was higher at Kuparuk than Teshekpuk in all years; however, due to the correlative nature of our data, we cannot determine the underlying causes with any certainty. We found mixed support for the concealed breeding strategy; females derived no benefit from nesting in areas with more willow (Salix spp.; measure of concealment) except that the observer effect diminished as willow cover increased. We suggest these patterns are due to conflicting predation pressures. Nest survival was not higher on islands (measure of seclusion) or with increased incubation constancy but was higher post-fox removal, indicating that predator control on breeding grounds could be a viable management option. Nest survival was negatively affected by our nest visitations, most likely by exposing the nest to avian scavengers. We recommend precautions be taken to limit the effects of nest visits in future studies and to consider them as a possible negative bias in estimated nest survival. Future models of the impacts of development within the breeding grounds of king eider should consider the influence of humans in the vicinity of nests. [ABSTRACT FROM AUTHOR]

The king eider ( Somateria spectabilis) is a migratory species of sea duck whose North American population is thought to be declining. We determined levels of cadmium, lead, selenium, and mercury in blood from female king eiders nesting in the central Canadian Arctic from 2001 to 2003. Year-to-year repeatability estimates were calculated from birds sampled in 2 or 3 years. Repeatability coefficients were 0.45, 0.35, 0.58, and 0.25 for cadmium, lead, selenium, and mercury, respectively. The first three were significantly different from zero ( p < 0.05), whereas the last approached significance (0.05 < p < 0.1). In 2001 and 2002, we also identified probable wintering locations of a subset of the birds. In both years, cadmium levels were higher and selenium levels were lower in birds inferred to have wintered in the eastern part of their range compared to those that had wintered in the west. There was little evidence that timing of breeding, timing of sampling, or body condition were related to levels of these trace elements, although in 1 of 2 years, lead levels were influenced by body condition and nest initiation date ( R 2 = 0.24) and cadmium levels were related to incubation day (partial R 2 = 0.04). Year-to-year repeatability of cadmium and selenium levels among individuals in this population of king eiders was likely influenced by where they wintered. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the timing, extent of migration and winter movements of King Eiders from 2002-2006 in the Bering Sea. The study found high variability in distances flow and migration events which range from less than a week to several months. According to the study, more than one third of King Eiders did not migrate after wing molt and stayed on or near wing-molting areas, and more than one half used various wintering sites in a given year.

Populations of several species of North American sea ducks have declined in the past few decades. Exposure to environmental contaminants, particularly metals, has been proposed as one of many possible factors contributing to these declines. Population dynamics are influenced by survival rates and breeding effort. In the present study, we examined the relationships between blood metal concentrations (Cd, Pb, Se, and Hg) and apparent annual survival and recapture probabilities (the latter as a surrogate for breeding effort) in adult females of two sea duck species, the king eider (Somateria spectabilis) and the white-winged scoter (Melanitta fusca), both of which have experienced declines in continental population during in recent years. No support was found for the hypothesis that exposure of white-winged scoters to these metals or of king eiders to Cd, Se, and Pb adversely affected probabilities of apparent annual survival. We detected a weak negative relationship (... = -0.833) between Hg and annual survival of king eiders, but the 90% confidence interval of the slope estimate overlapped zero (-2.439 to +0.672). Recapture probabilities were unrelated to concentrations of Cd, Se, and Pb in either species. Evidence indicated that Hg concentrations affected recapture probability in white-winged scoters (... = -194.77; 90% confidence interval, -203.770 to -185.778). Mercury levels were low in both species, and blood samples may not adequately represent long-term exposure to Hg. Therefore, conclusions regarding Hg effects on these birds should be considered with caution. [ABSTRACT FROM AUTHOR]

Coastal and offshore waters of Southwest Greenland are internationally important wintering areas for king eiders ( Somateria spectabilis) breeding in eastern Canadian Arctic and in northwestern Greenland. This paper presents the first assessment of their winter diet. Based on esophageal-proventricular samples from 26 females (13 juveniles and 13 older birds) and 15 males (11 juveniles and four older birds) collected in 2000–2002 (November–May) in coastal waters of Nuuk, we identified 28 prey species. The diet consisted of almost equal proportions (aggregate fresh mass) of polychaetes, echinoderms, crustaceans and molluscs. The dominant prey species were Pectinaria spp . (26.8%), Strongylocentrotus droebachiensis (18.4%), Mya eideri (11.2%) and Hyas araneus (9.7%). The polychaetes have previously been identified as important prey for eiders in Greenland, but apparently not outside Greenland. Compared with a diet study of common eiders Somateria mollissima from the same wintering area, the king eiders consumed significantly less bivalves and significantly more echinoderms. This difference corresponded with observations that common eiders were feeding in shallow waters, while king eiders were feeding in deeper waters farther from the shore. Benthic surveys are needed to confirm that diet corresponds with prey availability. [ABSTRACT FROM AUTHOR]

We estimated areas used by king eiders (Somateria spectabilis) in the Alaskan Beaufort Sea, how distributions of used areas varied, and characteristics that explained variation in the number of days spent at sea, to provide regulatory agencies with baseline data needed to minimize impacts of potential offshore oil development. We implanted sixty king eiders with satellite transmitters at nesting areas on the North Slope of Alaska, USA, in 2002-2004. More than 80% of marked eiders spent >2 weeks staging offshore prior to beginning a postbreeding molt migration. During postbreeding staging and migration, male king eiders had much broader distributions in the Alaskan Beaufort Sea than female eiders, which were concentrated in Harrison and Smith Bays. Distribution did not vary by sex during spring migration in the year after marking. Shorter residence times of eiders and deeper water at locations used during spring migration suggest the Alaskan Beaufort Sea might not be as critical a staging area for king eiders during prebreeding as it is postbreeding. Residence time in the Beaufort Sea varied by sex, with female king eiders spending more days at sea than males in spring and during postbreeding. We conclude the Alaskan Beaufort Sea is an important staging area for king eiders during postbreeding, and eider distribution should be considered by managers when mitigating for future offshore development. We recommend future studies examine the importance of spring staging areas outside the Alaskan Beaufort Sea. [ABSTRACT FROM AUTHOR]

Events during duckling growth can influence waterfowl population dynamics. To gain insight into King Eider (Somateria spectabilis) brood ecology, we monitored 111 and 46 individually marked ducklings from broods of 23 and 11 radiomarked King Eiders during 2000 and 2001, respectively. We used capture-mark-resight data to model apparent survival of King Eider ducklings and broods, and multistratum analysis to estimate probabilities of (1) movement among habitats and (2) apparent survival of ducklings that used various habitats. In addition, we recorded length of stay for 7 and 18 radiomarked females with failed nesting attempts during 2000 and 2001, respectively. Complete loss of individual broods accounted for 84% of all duckling mortality (106 of 126 mortalities), with most brood loss (74%; 17 of 23 broods lost) within the first two days after hatch. Estimated apparent survival of ducklings to 24 days of age was 0.10 (95% CI: 0.05 to 0.15). Apparent survival of broods was estimated to be 0.31 (95% CI: 0.13 to 0.50). Our data suggested an interaction between female size and hatch date, whereby larger females whose ducklings also hatched earlier raised more ducklings than either small females or those with ducklings that hatched later. Overland brood movements ≥1 km occurred in both years, and survival was greatest for ducklings on smaller ponds away from the central nesting area at Karrak Lake, Nunavut. Females that experienced nest failure and total brood loss left the study area earlier than females with surviving ducklings. [ABSTRACT FROM AUTHOR]

Intraspecific sexual differences, high variation, and positive allometry of sexually-selected external display structures are common. Many sexually-selected anatomical specializations occur in the avian vocal tract but intraspecific variation and allometry have been investigated little. The tracheal bulla bulla syringealis occurs in males of most duck species. We quantified variation and size-scaling of the bulla, plus sexual differences in size of trachea, bronchi, and vocal muscles, for 62 common eiders Somateria mollissima and 51 king eiders S. spectabilis. Trends were similar in both species. Bullar ossification and definitive size occurred early in life: bullar size did not differ between first-year and older males. Bullar size did not vary more than size of other body parts (CVs of 3.4–7.0% for bullar length and breadth). Bullar size scaled to body size with negative allometry or isometry. Vocal muscles were 10–50% thicker in males than females, a much greater sexual difference than in body size (CVs of 3–6% on linear body-size variables). Vocal muscles were larger on the left side in both sexes and bilateral asymmetry was slightly more pronounced in males. Low variation and a trend towards negative allometry suggest that bullar size is under stabilizing selection; if bullar size affects vocal attributes of voice, then the latter cannot be condition-dependent. We recommend comparative research on vocal communication, vocal individuality and vocal-tract anatomy and function in eiders and other ducks. [ABSTRACT FROM AUTHOR]

King Eiders (Somateria spectabilis) breeding in western Canada and Alaska molt wing feathers and spend the winter in remote areas of the Bering Sea, precluding direct observation. To characterize timing of migration and habitat used by King Eiders during the nonbreeding period, we collected location data for 60 individuals (27 females and 33 males) over three years from satellite telemetry and utilized oceanographic information obtained by remote sensing. Male King Eiders dispersed from breeding areas, arrived at wing molt sites, and dispersed from wing molt sites earlier than females in all years. Males arriving earlier at wing molt sites molted flight feathers at higher latitudes. Distributions of molt and winter locations did not differ by sex or among years. Of the variables considered for analysis, distance to shore, water depth, and salinity appeared to best describe King Eider habitat throughout the nonbreeding period. King Eiders were located closer to shore, in shallower water with lower salinity than random locations. During the winter, lower ice concentrations were also associated with King Eider locations. This study provides some of the first large-scale descriptions of King Eider migration and habitat outside the breeding season. [ABSTRACT FROM AUTHOR]