King Eiders Research Articles

Dispersal, movements and site fidelity of post‐fledging King EidersSomateria spectabilisand their attendant females

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 EidersSomateria spectabilisin 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.

Age-specific in situ recruitment of female King Eiders estimated with mark–recapture

ABSTRACT 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 influenc...

Changing distribution of flocking sea ducks as non-regenerating food resources are depleted

Sutherland & Anderson (1993; J Theor Biol 160:223–230) considered how the distribution of consumers should change as prey resources fixed at the start of a period of exploitation are depleted by foraging activities. Their model predicts that consumers initially aggregate on a single or a few patches offering the highest feeding rate. As the prey density in those patches is reduced, the feeding rate declines to the level attainable at the next best patches, which are then also exploited. Therefore, an increase in the number of flocks and a decline in flock size should be observed as individuals spread out over the available feeding opportunities. Further, once occupied, a patch is exploited for the remainder of the winter. We tested these predictions with winter survey data on the number, size and location of flocks of common eiders Somateria mollissima and king eiders S. spectabilis wintering in Kvalsundet, a sound in northern Norway. Both species are benthivorous, and there is little or no growth or recruitment of their prey in winter at high-latitude sites. The green sea urchin Strongylocentrotus droebachiensis was the dominant prey of both species in Kvalsundet, and the density of this prey species declined over the winter in kelp beds, the preferred winter habitat of common eiders. Our data showed that both common and king eiders began their winter periods in Kvalsundet aggregated into a few large flocks. As the winter progressed, the distribution changed and birds gathered into more and smaller flocks. In the case of common eiders, flock locations remained fixed once a foraging location began to be exploited. King eiders formed a few large flocks early in the season which drifted in heavy tidal currents, but when these split up into smaller flocks in February, they started to exploit fixed locations. We interpret these results as consistent with the Sutherland & Anderson model.

The Body Size-Dependent Diet Composition of North American Sea Ducks in Winter

Daily food requirements scale with body mass and activity in animals. While small species of birds have higher mass-specific field metabolic rates than larger species, larger species have higher absolute energy costs. Under energy balance, we thus expect the small species to have a higher energy value diet. Also the weight and time constraints for flighted and diurnal foragers should set a maximum to the amount of prey items taken in one meal and to the daily number of meals, respectively. Further, avoidance of competition causes the species to reduce the amount of shared prey in their diet. Some diet segregation is therefore to be expected between species. We tested these hypotheses and investigated the role of body mass in the diet composition of 12 sea duck species (Somateria mollissima, Somateria spectabilis, Somateria fischeri, Polysticta stelleri, Bucephala clangula, Bucephala islandica, Bucephala albeola, Melanitta nigra, Melanitta perspicillata, Melanitta deglandi, Histrionicus histrionicus and Clangula hyemalis) wintering in North America. This study was based on a literature survey with special emphasis given to the diet data from the former US Bureau of Biological Survey. The data supported our hypothesis that the energy value of winter diet of sea ducks scales negatively with body mass. Diet diversity also scaled negatively with body mass. Our results suggest the existence of a minimum for the energy value of avian diets.

Modeling probability of waterfowl encounters from satellite imagery of habitat in the central Canadian arctic

We used aerial survey and corresponding digital land cover data to develop species-habitat models to describe breeding-ground distributions and landscape-level habitat associations of greater white-fronted geese (Anser albifrons), Canada (Branta canadensis) and cackling geese (B. hutchinsii), tundra swans (Cygnus columbianus), king eiders (Somateria spectabilis), and long-tailed ducks (Clangula hyemalis). We then used habitat associations in the Queen Maud Gulf Migratory Bird Sanctuary and the Rasmussen Lowlands, Nunavut, Canada, in models to predict distributions of focal species in each study area. We used the receiver operating characteristic (ROC) method and the area-under-the-curve (AUC) metric to evaluate predictive accuracy (hereafter, quality) of models. In the Queen Maud Gulf, AUC values suggested reasonable model discrimination for white-fronted geese, Canada geese, and tundra swans (i.e., AUC > 0.7). Quality of species-habitat models for king eiders and long-tailed ducks was less than other species considered, but these models still predicted encounters and non-encounters significantly better than the null model. For all species, quality of species-habitat models was lesser for the Rasmussen Lowlands than for the Queen Maud Gulf, although discrimination ability for Rasmussen Lowland distributions remained significantly better than corresponding null models for geese and swans, but not for seaducks. Our research suggested that species' distributions modeled with landscape-level habitat data is a tractable method to 1) identify habitat associations, 2) determine key habitats and regions, and 3) predict probable summer distributions of some waterfowl species over relatively large areas of the arctic from satellite imagery. © 2013 The Wildlife Society.

Habitat used by common and king eiders in spring in the southeast Beaufort Sea and overlap with resource exploration

AbstractThe southeast Beaufort Sea is a critical spring staging area for common and king eiders (Somateria mollissima v‐nigrum, S. spectabilis), and is for many the final stop before they reach their breeding grounds throughout the western Canadian Arctic. The region also has significant oil and gas potential, and the recent approval of a pipeline through the Mackenzie Valley may make development of these resources economically viable. We used satellite telemetry to determine the distribution and habitat use of eiders staging in the southeast Beaufort Sea in spring, and the overlap of eiders with oil and gas exploration. From 2004 to 2009, we monitored 51 eiders equipped with platform terminal transmitters (PTTs) throughout spring migration (May–June). We compared the marine habitats used by each species, and evaluated habitat preferences using resource selection functions. The location and extent of the flaw lead (open water along the interface between mobile pack ice and stationary landfast ice) at the time when eiders were staging varied among years, but both species showed a strong preference for use of flaw lead habitats. This preference was stronger for common eiders than for king eiders, which also used pack ice extensively. Common eiders generally occurred near the landfast ice edge, whereas king eiders were just as often nearer to the pack ice edge of the flaw lead. Average water depth (±SE) for common eiders was 22 ± 2 m compared to 30 ± 1 m for king eiders. Kernel density estimators showed that eiders generally occurred in lower densities in areas of otherwise suitable habitat off the Mackenzie River delta. We suggest that this is a result of the highly turbid water discharged by the Mackenzie River, which limits visibility. Oil and gas exploration overlapped significantly with the areas used by eiders. The high density of birds using the restricted and ice‐rich flaw lead habitats indicates that an accidental spill in the region could be catastrophic for Canada's western Arctic eider populations. © 2013 The Wildlife Society.

Population dynamics of king eiders breeding in northern Alaska

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 ( = 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.

ЗАМЕТКИ О ПТИЦАХ ОХОТСКОГО РАЙОНА ХАБАРОВСКОГО КРАЯ

New observation data describe the distribution, number and status of 10 rare and understudied species of birds in Okhotsky district, Khabarovsky Krai. The Great Egret Casmerodius albus, Red-breasted Goose Branta ruficollis, Mandarin Duck Aix galericulata, Baer's Pochard Aythya baeri, King Eider Somateria spectabilis, Watercock Gallicrex cinerea were registered in the studied territory for the first time.

Use of Nape Tags for Marking Offspring of Precocial Waterbirds

Abstract. Individualized markers that allow organisms to be identified without recapture are invaluable for studies of survival, movement, and behavior. Nape tags consisting of brass safety pins with unique combinations of two or three colored plastic beads were used to mark 5,868 American Coot (Fulica americana) chicks and 331 Ruddy Duck (Oxyura jamaicensis), 157 King Eider (Somateria spectabilis) and 664 White-winged Scoter (Melanitta fusca deglandi) ducklings. These markers allowed for documentation of parent-offspring interactions, post-hatching survival, brood movements and brood-mixing behaviors. Nape tags were inexpensive, easy to make, easy to observe with binoculars or spotting scopes and provided over 100 two-bead or 1,000 three-bead color combinations for individual identification. For coots, there was no evidence of color biases affecting parental care or offspring survival, although some colors (white, yellow) were easier to detect than others (brown). The only observed problem was marker los...

Abundance and energy requirements of eiders (Somateria spp.) suggest high predation pressure on macrobenthic fauna in a key wintering habitat in SW Greenland

The number of common eiders (Somateriamollissima 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−2 and 28.4 g ash-free dry mass (AFDM) m−2 (647 kJ m−2), respectively. Annual production was estimated at 13.9 g AFDM m−2 year−1 (317 kJ m−2 year−1). 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.

King Eider Foraging Effort During the Pre-Breeding Period in Alaska

Abstract. For reproduction, many arctic-nesting migratory birds rely on nutrients obtained on the breeding grounds, so they devote sufficient time to foraging immediately prior to nesting. However, little is known about the increase in foraging effort necessary to meet the energetic requirements of reproduction. In early June 2006 and 2008, we quantified the proportion of time spent foraging before breeding by a large sea duck, the King Eider (Somateria spectabilis), on its breeding grounds in northern Alaska. During >235 hours of behavioral observations, both male and female King Eiders spent >50% of the day loafing (resting, sleeping, comfort behavior, or being alert). Females foraged on average 30% of the time (mean 7.2 hr day-1,95% CI 6.0-8.4 hr day-1), three times as much as males (9%; 2.3 hr day-1, 95% CI 1.5–2.8 hr day-1). The most common prey in ponds where the eiders foraged were chironomid larvae and worms ranging in length from 1 to 30 mm. If the King Eider's daily energy expenditure on its bre...

Health Evaluation of Western Arctic King Eiders (Somateria spectabilis)

The western arctic population of King Eiders (Somateria spectabilis) has declined by >50% in recent years. A health assessment was conducted for adult King Eiders breeding on the north slope of Alaska, USA, to evaluate body condition (n=90, 2002-2006) and baseline biochemical and hematologic values (n=20-30, 2005-2006). Body condition for males and females was excellent. Total protein, calcium, alkaline phosphatase, amylase, and globulin were significantly higher in females than in males, likely because of differences in reproductive physiology. These baseline health data can be used to promote conservation of King Eiders and other closely related species of concern.

Patterns of use and distribution of king eiders and black scoters during the annual cycle in northeastern Bristol Bay, Alaska

Northeastern Bristol Bay, Alaska, which includes three large estuaries, is used by multiple sea duck species during the annual cycle. Limited aerial surveys indicate that this area supports tens of thousands of king eiders and black scoters during spring migration and the autumn molt. Existing satellite telemetry data were used to assess the temporal patterns of habitat use and spatial distribution of king eiders and black scoters in northeastern Bristol Bay throughout the annual cycle. King eiders used northeastern Bristol Bay during all months of the annual cycle and black scoters used the area during spring through fall. Both species exhibited a similar seasonal pattern of use that corresponded with the timing of life-cycle stages. Abundance of both species was highest during spring migration and the autumn molting period and lowest during summer. Use by king eiders did not occur during all winter months in every year of the study. King eiders were more broadly distributed than black scoters and were located farther from shore in deeper water. Core use areas had minimal overlap, suggesting a degree of spatial segregation between species and a preference for different habitats in northeastern Bristol Bay. Further study of potential variation in invertebrate community structure that may correlate with the observed interspecific spatial segregation in habitat use is needed to determine preferred forage and describe habitat requirements for each species. Such information is necessary to assess the potential impact that future anthropogenic or environmental changes may have on habitat quality of northeastern Bristol Bay and demography of Pacific sea duck populations that use this area.

Migration patterns, breeding and moulting locations of king eiders wintering in north-eastern Norway

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.

King eiders use an income strategy for egg production: a case study for incorporating individual dietary variation into nutrient allocation research

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.

Incubation behavior of king eiders on the coastal plain of northern Alaska

Incubating birds balance their energetic demands during incubation with the needs of the develop- ing 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 availabil- ity, and thus are likely to rely heavily on endogenous reserves to maintain high incubation constancy. We exam- ined 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 Teshek- puk. 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 0.3). Daily constancy increased 1% with every 5°C increase in minimum daily temperature (! min = 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.

Age-Specific Survival Estimates of King Eiders Derived from Satellite Telemetry

Abstract. Age- and sex-specific survival and dispersal are important components in the dynamics and genetic structure of bird populations. For many avian taxa survival rates at the adult and juvenile life stages differ, but in long-lived species juveniles' survival is logistically challenging to study. We present the first estimates of hatch-year annual survival rates for a sea duck, the King Eider (Somateria spectabilis), estimated from satellite telemetry. From 2006 to 2008 we equipped pre-fiedging King Eiders with satellite transmitters on breeding grounds in Alaska and estimated annual survival rates during their first 2 years of life with known-fate models. We compared those estimates to survival rates of adults marked in the same area from 2002 to 2008. Hatch-year survival varied by season during the first year of life, and model-averaged annual survival rate was 0.67 (95% CI: 0.48–0.80). We did not record any mortality during the second year and were therefore unable to estimate second-year surviva...

Effects of Lipid Extraction on Stable Isotope Ratios in Avian Egg Yolk: Is Arithmetic Correction a Reliable Alternative?

ABSTRACT. Many studies of nutrient allocation to egg production in birds use stable isotope ratios of egg yolk to identify the origin of nutrients. Dry egg yolk contains >50% lipids, which are known to be depleted in 13C. Currently, researchers remove lipids from egg yolk using a chemical lipid-extraction procedure before analyzing the isotopic composition of protein in egg yolk. We examined the effects of chemical lipid extraction on δ13C, δ15N, and δ34S of avian egg yolk and explored the utility of an arithmetic lipid correction model to adjust whole yolk δ13C for lipid content. We analyzed the dried yolk of 15 captive Spectacled Eider (Somateria fischeri) and 20 wild King Eider (S. spectabilis) eggs, both as whole yolk and after lipid extraction with a 2:1 chloroform:methanol solution. We found that chemical lipid extraction leads to an increase of (mean ± SD) 3.3 ± 1.1‰ in δ13C, 1.1 ± 0.5‰ in δ15N, and 2.3 ± 1.1‰ in δ34S. Arithmetic lipid correction provided accurate values for lipid-extracted δ13C in...

A Common Eider × King Eider Hybrid Captured on the Kent Peninsula, Nunavut

On 25 June 2002, we captured and recorded measurements of a male common eider (Somateria mollissima) × king eider (S. spectabilis) hybrid at Nauyak Lake, on the Kent Peninsula, Nunavut. This is the first documented capture of a hybrid eider, rarely observed in North America. Structural body measurements and mass of the hybrid were intermediate compared to those of Pacific common eiders (S. m. v-nigrum) at the same study site and king eiders at a nearby study site during the same time of year. The plumage of the captured hybrid had characteristics of both parent species. Mate pairing on overlapping spring staging or wintering areas of common and king eiders may occasionally result in hybrid offspring.

Composition of Eiders Harvested in Newfoundland

Abstract 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 souther...