Sea Ducks Research Articles

Increasing nest predation will be insufficient to maintain polar bear body condition in the face of sea ice loss.

Climate change can influence interspecific interactions by differentially affecting species-specific phenology. In seasonal ice environments, there is evidence that polar bear predation of Arctic bird eggs is increasing because of earlier sea ice breakup, which forces polar bears into nearshore terrestrial environments where Arctic birds are nesting. Because polar bears can consume a large number of nests before becoming satiated, and because they can swim between island colonies, they could have dramatic influences on seabird and sea duck reproductive success. However, it is unclear whether nest foraging can provide an energetic benefit to polar bear populations, especially given the capacity of bird populations to redistribute in response to increasing predation pressure. In this study, we develop a spatially explicit agent-based model of the predator-prey relationship between polar bears and common eiders, a common and culturally important bird species for northern peoples. Our model is composed of two types of agents (polar bear agents and common eider hen agents) whose movements and decision heuristics are based on species-specific bioenergetic and behavioral ecological principles, and are influenced by historical and extrapolated sea ice conditions. Our model reproduces empirical findings that polar bear predation of bird nests is increasing and predicts an accelerating relationship between advancing ice breakup dates and the number of nests depredated. Despite increases in nest predation, our model predicts that polar bear body condition during the ice-free period will continue to decline. Finally, our model predicts that common eider nests will become more dispersed and will move closer to the mainland in response to increasing predation, possibly increasing their exposure to land-based predators and influencing the livelihood of local people that collect eider eggs and down. These results show that predator-prey interactions can have nonlinear responses to changes in climate and provides important predictions of ecological change in Arctic ecosystems.

Sex-specific survival of adult common eiders in Nova Scotia, Canada

Common eiders (Somateria mollissima) are large sea ducks with a circumpolar distribution and have high cultural significance to sport hunters and indigenous peoples in many countries. Their gregarious habits, including colonial breeding and forming large flocks during migration and winter, make eiders susceptible to environmental stressors during breeding and non-breeding seasons. Our objective was to assess whether low adult survivorship could be contributing to suspected local population declines in Nova Scotia, Canada. We banded molting male and breeding female common eiders along the marine coastline of Nova Scotia and recaptured them in later years. We found that from 1997 to 2011, when males and females were banded, male survival (S) was high (S = 0.92; 95% CI = 0.87–0.95), whereas female survival was approximately 10% lower (S = 0.83; 95% CI = 0.78–0.87) and at a level comparable to what has been reported in other regions of the world where eider populations are thought to be in decline. Recovery rates (f) of harvested male and female eiders were indistinguishable (f = 0.013; 95% CI = 0.010–0.016), suggesting that lower female survival is attributable to factors other than hunting. Supplementary analyses using a longer-term data set for females only (1978–2011) and including live recapture data indicated that female survival rates have not changed markedly during the past 40 years and that the emigration rate from colonies is low (∼6%). We conclude that to successfully conserve this population, sources of non-harvest female mortality should be investigated and used to develop targeted management solutions. We speculate that one of those sources of mortality is predation on females at breeding colonies, notably from eagles and mustelids. © 2016 The Wildlife Society.

Validating the deuterium dilution method to measure body composition of common eider

ABSTRACTWe conducted the first validation of the deuterium dilution method as a nonlethal technique for estimating body composition of a sea duck. We captured male (n = 11) and female (n = 8) American common eiders (Somateria mollissima dresseri) during winters of 2011–2012 and 2012–2013 in southern New England, USA, and compared their directly measured body composition with that estimated using deuterium‐dilution. The best‐supported linear regression models predicted wet lean and fat mass with, on average, 2.0% and 20.2% relative errors, respectively. The deuterium dilution method provides field biologists and managers with a nonlethal method for accurately estimating body composition of common eider during winter. The method is broadly applicable to other migratory birds and can be used to evaluate the effects of ecological and anthropogenic drivers on body composition dynamics. © 2016 The Wildlife Society.

Body composition dynamics of common eider during winter: An application of the deuterium dilution method

ABSTRACTThe nearshore and offshore waters of southern New England provide some of the most important wintering habitat for sea ducks in North America. Understanding changes in sea duck body composition during winter could provide insights into current habitat quality and potential effects of anthropogenic disturbances on the body condition of sea ducks. We used the deuterium dilution method, a nonlethal approach, to investigate intraseasonal variation and differences between genders in body composition of 86 adult common eiders (Somateria mollissima) during winter (2011 and 2012) in southern New England. Both male (n = 39) and female (n = 47) eiders increased fat mass by 75% in late winter compared with early winter. Wet lean mass of males remained constant throughout the winter, while that of females decreased by 10%. These seasonal increases in fat stores of eider suggest that birds were able to secure adequate resources to improve their body condition over winter. Our estimates of body composition of eider during winter in southern New England can be used as a baseline when conducting future research to evaluate effects of anthropogenic disturbance and disease. © 2016 The Wildlife Society.

Trace Elements in Sea Ducks of the Alaskan Arctic Coast: Patterns of Variation Among Species, Sexes, and Ages.

Climate change and increasing industrialization in the Arctic call for the collection of reference data for assessing changes in contaminant levels. For migratory birds, measuring and interpreting changes in traceelement burdens on Arctic breeding areas require insights into factors such as sex, body size, or wintering area that may modify patterns independently of local exposure. In the Alaskan Arctic, we determined levels of trace elements in liver and kidney of common eiders (Somateria mollissima) and long-tailed ducks (Clangula hyemalis) from the Prudhoe Bay oil field and of king eiders (S. spectabilis) and threatened spectacled eiders (S. fischeri) and Steller's eiders (Polystica stelleri) from near the town of Barrow. Small-bodied Steller's eiders and long-tailed ducks from different locations had similarly low levels of selenium (Se), cadmium (Cd), and copper (Cu), perhaps reflecting high mass-specific rates of metabolic depuration during long spring migrations through areas of low exposure. In larger species, Se, Cd, and Cu concentrations were higher in adults than juveniles suggesting that these elements were acquired in nonbreeding marine habitats. Adult male spectacled eiders had exceptionally high Se, Cd, and Cu compared with adult females, possibly because of depuration into eggs and longer female occupancy of nonmarine habitats. Adult female common eiders and juvenile long-tailed ducks at Prudhoe Bay had high and variable levels of Pb, potentially due to local exposure. Explanations for substantial variations in Hg levels were not apparent. Further research into reasons for differing element levels among species and sexes will help clarify the sources, pathways, and risks of exposure.

Does Water Temperature Affect the Timing and Duration of Remigial Moult in Sea Ducks? An Experimental Approach.

Aquatic birds have high cost of thermoregulation, especially during the moulting period, yet the effect of water temperature on the moulting strategy of aquatic birds has rarely been studied. Our general hypothesis is that energy savings associated with lower thermoregulation costs would be allocated to moulting processes. We predicted that aquatic birds moulting in warm water would have a higher level of body reserves, a faster growth rate of feathers, and an earlier remigial moult onset compared with birds moulting in cold water. We used the common eider (Somateria mollissima dresseri), a large sea duck, as the model species. Captive individuals were experimentally exposed to warm (18°C) and cold (8°C) water treatments during a three year period with individuals swapped between treatments. We found a similar feather growth rate for the two water temperature treatments and in contrast to our predictions, eiders exposed to warm water had a lower body mass and showed a delayed onset of remigial moult of approximately 7 days compared with those exposed to cold water. Our data indicate that body mass variations influence the timing of moult in unexpected ways and we suggest that it likely controls the occurrence of wing moult through a hormonal cascade. This study emphasizes the importance of improving our knowledge of the effects of water temperature on remigial moult of aquatic birds, to better assert the potential effects of global warming on their survival.

Ecology and Conservation of North American Sea DucksEcology and Conservation of North American Sea Ducksedited by Jean-Pierre L. Savard, Dirk V. Derksen, Dan Esler, and John M. Eadie.Studies in Avian BiologyNumber 46. 2015. Cooper Ornithological Society, and CRC Press, Boca Raton, Florida. xxii + 584 pp., 4 color plates, 98 text figures. $119.96 (hardcover). ISBN 13:978-1-4822-4897-5.

The editors of this volume have accomplished a remarkable assemblage of authors and topics on the sea duck tribe (Mergini) that has not been covered before in a single major treatise. While waterfowl (Anseriformes) are, arguably, the family of wild birds that have been most thoroughly studied by scientists, the sea ducks have been relatively poorly covered because of the remote habitats in which most of them are found at all times of the year. Only a few, such as the Common Goldeneye (Bucephala clangula), Barrow’s Goldeneye (B. islandica), Bufflehead (B. albeola), and Hooded Merganser (Lophodytes cucullatus) are accessible fairly easily to researchers. The other 11 extant species nest primarily in boreal, Arctic, or sub-Arctic habitats, and typically winter in even more remote oceanic locations. Nevertheless, waterfowl are one of the best inventoried of all North American birds, and sea ducks have been the subject of several additional surveys designed to monitor specific populations (Chapter 1). Most sea duck populations are uncommon, and many have been declining in number to the point that North American populations of two of the eiders, Spectacled (Somateria fischeri) and Steller’s (Polysticta stelleri), are listed under the U.S. Endangered Species Act. In Canada, eastern populations of Harlequin duck (Histrionicus histrionicus) and Barrow’s goldeneye (Bucephala islandica) are Species of Concern. The most significant upshot of this growing concern has been the formation of the Sea Duck Joint Venture of the North American Waterfowl Management Plan in 1998 (Sea Duck Joint Venture Management Board 2008, Sea Duck Joint Venture 2013). This has provided a superb forum for the sea duck specialists of the world to meet, plan, coordinate, and implement new science and to take other steps to stimulate progress in sea duck conservation. The 27 authors of this volume represent essentially all the individuals and government agencies and academic institutions that have driven the tremendous progress made since 1998. The fifteen chapters cover every major topic that one would expect. This is a departure from the more typical approach to taxonomic groups which usually cover each topic on a species-by-species basis. This was a thoughtful tactic as it encourages the broader community of scientists to integrate sea duck information into their analyses while, at the same time, provides important new perspectives for those more narrowly focused on waterfowl. Some new information is provided and the literature reviewed is thorough with all the common sources cited. In addition, a great deal of less common material is integrated by specialists in the general topics. These qualities contribute importantly to the editors’ central objective ‘‘to highlight

The winter abundance and distribution of birds in western peter the Great Bay in the Sea of Japan

The data on the abundance and distribution of sea birds and waterfowl at the coast of southern Primorye and distribution diagrams of the sea ducks along the surveyed coast in winter season are given. The dependence of the presence of the birds in certain coastal areas on the winter ice condition was revealed.

Harlequin Ducks (<i>Histrionicus histrionicus</i>) Scavenge Sea Urchin Fragments from Foraging Sea Otters (<i>Enhydra lutris</i>)

Foraging animals may risk association with potential predators to obtain otherwise inaccessible prey. We observed this strategy in wintering Harlequin Ducks (Histrionicus histrionicus) scavenging fragments of Red Sea Urchins (Mesocentrotus franciscanus) from foraging Sea Otters (Enhydra lutris) that were re-occupying an area from which they had been ecologically absent since about 1850. Harlequin Ducks, like other sea ducks, have not previously been reported scavenging from other birds or mammals. In British columbia, Red Sea Urchins have reached large sizes and densities since the removal of Sea Otter predators by the marine fur trade in the 18th and 19th centuries. Observations of Sea Otters and Harlequin Ducks were made in 4 areas, spanning a time gradient of Sea Otter occupation from 1 to 5 years. During 3 months of observations (December 2013 – February 2014), Harlequin Ducks were associated with foraging Sea Otters only at sites that were recently occupied by Sea Otters (≤ 2 months), where the proportion of urchins in Sea Otter diets was highest and where the ducks acquired urchin fragments from foraging Sea Otters. We suggest that Sea Otters re-occupying their historic range and consuming predominantly large Red Sea Urchins provide a temporarily available prey subsidy for Harlequin Ducks. Our observations document a novel effect of Sea Otters providing important prey supplementation to a marine bird when foraging in urchin-rich habitats, contributing to the overall role of Sea Otters as a keystone species.

Spatial Genetic Structure of Long-tailed Ducks (<i>Clangula hyemalis</i>) among Alaskan, Canadian, and Russian Breeding Populations + Supplementary Appendix Tables S1 and S2 (See Article Tools)

<p class="Pa5" style="text-align: justify; text-justify: inter-ideograph;"><span style="font-size: 10.0pt; color: #221e1f;">Arctic ecosystems are changing at an unprecedented rate. How Arctic species are able to respond to such environmental change is partially dependent on the connections between local and broadly distributed populations. For species like the Long-tailed Duck (<em>Clangula hyemalis</em>), we have limited telemetry and band-recovery information from which to infer population structure and migratory connectivity; however, genetic analyses can offer additional insights. To examine population structure in the Long-tailed Duck, we characterized variation at mtDNA control region and microsatellite loci among four breeding areas in Alaska, Canada, and Russia. We observed significant differences in the variance of mtDNA haplotype frequencies between the Yukon-Kuskokwim Delta (YKD) and the three Arctic locations (Arctic Coastal Plain in Alaska, eastern Siberia, and central Canadian Arctic). However, like most sea duck genetic assessments, our study found no evidence of population structure based on autosomal microsatellite loci. Long-tailed Ducks use multiple wintering areas where pair formation occurs with some populations using both the Pacific and Atlantic Oceans. This situation provides a greater opportunity for admixture across breeding locales, which would likely homogenize the nuclear genome even in the presence of female philopatry. The observed mtDNA differentiation was largely due to the presence of two divergent clades: (A) a clade showing signs of admixture among all breeding locales and (B) a clade primarily composed of YKD samples. We hypothesize that the pattern of mtDNA differentiation reflects some degree of philopatry to the YKD and isolation of two refugial populations with subsequent expansion and admixture. We recommend additional genetic assessments throughout the circumpolar range of Long-tailed Ducks to further quantify aspects of genetic diversity and migratory connectivity in this species.</span></p>

The palaeobiology of high latitude birds from the early Eocene greenhouse of Ellesmere Island, Arctic Canada.

Fossils attributable to the extinct waterfowl clade Presbyornithidae and the large flightless Gastornithidae from the early Eocene (~52–53 Ma) of Ellesmere Island, in northernmost Canada are the oldest Cenozoic avian fossils from the Arctic. Except for its slightly larger size, the Arctic presbyornithid humerus is not distinguishable from fossils of Presbyornis pervetus from the western United States, and the Gastornis phalanx is within the known size range of mid-latitude individuals. The occurrence of Presbyornis above the Arctic Circle in the Eocene could be the result of annual migration like that of its living duck and geese relatives, or it may have been a year-round resident similar to some Eocene mammals on Ellesmere and some extant species of sea ducks. Gastornis, along with some of the mammalian and reptilian members of the Eocene Arctic fauna, likely over-wintered in the Arctic. Despite the milder (above freezing) Eocene climate on Ellesmere Island, prolonged periods of darkness occurred during the winter. Presence of these extinct birds at both mid and high latitudes on the northern continents provides evidence that future increases in climatic warming (closer to Eocene levels) could lead to the establishment of new migratory or resident populations within the Arctic Circle.

Patterns of cryptic host specificity in duck lice based on molecular data.

Documenting patterns of host specificity in parasites relies on the adequate definition of parasite species. In many cases, parasites have simplified morphology, making species delimitation based on traditional morphological characters difficult. Molecular data can help in assessing whether widespread parasites harbour cryptic species and, alternatively, in guiding further taxonomic revision in cases in which there is morphological variation. The duck louse genus Anaticola (Phthiraptera: Philopteridae), based on current taxonomy, contains both host-specific and widespread species. Mitochondrial and nuclear DNA sequences of samples from this genus were used to document patterns of host specificity. The comparison of these patterns with morphological variations in Anaticola revealed a general correspondence between the groups identified by DNA sequences and morphology, respectively. These results suggest that a more thorough taxonomic review of this genus is needed. In general, the groups identified on the basis of molecular data were associated with particular groups of waterfowl (e.g. dabbling ducks, sea ducks, geese) or specific biogeographic regions (e.g. North America, South America, Australia, Eurasia).

Nest usurpation by a common eider toward a long-tailed duck

Intraspecific and non-obligate brood parasitism and nest takeover is well documented in common eiders ( Somateria mollissima borealis ) nesting in the Arctic. However, we report the takeover of a long-tailed duck ( Clangula hyemalis ) nest by a female common eider on Nasaruvaalik Island, Nunavut, Canada. The high nesting density due to limited habitat in the region may have contributed to this seemingly risky behaviour, which provides no clear benefits to the eider. Keywords: Nest takeover; sea ducks; Somateria mollissima ; Clangula hyemalis ; High Arctic; limited habitat. (Published: 26 October 2016) Citation: Polar Research 2016, 35 , 32414, http://dx.doi.org/10.3402/polar.v35.32414

Shifts in the distribution of molting Spectacled Eiders (Somateria fischeri) indicate ecosystem change in the Arctic

ABSTRACT Shifts in the distribution of benthivorous predators provide an indication of underlying environmental changes in benthic-mediated ecosystems. Spectacled Eiders (Somateria fischeri) are benthivorous sea ducks that spend the nonbreeding portion of their annual cycle in the Bering, Chukchi, Beaufort, and East Siberian seas. Sea ducks generally molt in biologically productive areas with abundant prey. If the distribution of eiders at molting areas matches prey abundance, spatial shifts may indicate changes in environmental conditions in the Arctic. We used a randomization procedure to test for shifts in the distribution of satellite telemetry locations received from Spectacled Eiders in the 1990s and 2008–2011 within 4 late-summer, ice-free molting areas: Indigirka–Kolyma, northern Russia; Ledyard Bay, eastern Chukchi Sea; Norton Sound, northeastern Bering Sea; and Mechigmenskiy Gulf, northwestern Bering Sea. We also tested for interannual and interdecadal changes in dive depth required to reach pre...

Avian Influenza Ecology in North Atlantic Sea Ducks: Not All Ducks Are Created Equal.

Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology.

Ecology and conservation of North American sea ducks

Ecology and conservation of North American sea ducks

Body and organ mass dynamics during remigial moult in a wing–foot-propelled diving sea duck: the Common Eider (Atlantic) (Somateria mollissima dresseri)

Body and organ dynamics, during remigial moult, have been mainly explored on geese, dabbling ducks, and foot-propelled diving ducks, but weakly on sea ducks. This study investigated the internal changes in a wing–foot-propelled sea duck to determine the adaptive strategies implemented. Forty-five male Common Eiders (Atlantic) (Somateria mollissima dresseri Sharpe, 1871), collected in the Gulf of St. Lawrence, were dissected; their body mass, muscle mass, and organ sizes were measured. We tested three hypotheses: (1) S. m. dresseri use a strategic reduction of body mass to reduce the flightlessness duration; (2) organs will exhibit changes consistent with a trade-off between function and maintenance to save and reallocate energy and proteins to feather growth; (3) S. m. dresseri would show lower flight muscle reduction than foot-propelled diving ducks. Somateria mollissima dresseri did not lose body mass, which does not support the first hypothesis. Atrophy of the heart followed by hypertrophy and opposite changes in leg muscle mass and gizzard mass are consistent with the second hypothesis. Flight muscle mass showed lower variations than in other ducks, validating the third hypothesis. We also suggest that the lipid depletion observed early in the moult could be a strategy to reduce foraging effort and minimize the risk of damaging the growing feathers.

Blue mussel (Mytilus edulis) quality of preferred prey improves digestion in a molluscivore bird (Common Eider,Somateria mollissima)

Benthivorous predators like sea ducks rely on abundant but low-quality food. Because they ingest whole blue mussels (Mytilus edulis L., 1758), including shells, they have to consume large quantities of food to maintain energy balance. Digestive processes may therefore limit energy assimilation in these predators, although selecting mussel types that minimize shell ingestion may improve foraging profitability. To test this prediction, we first quantified mussel quality from different sizes and habitats by measuring energy content and various features of mussel morphology. Then, we conducted digestive experiments on captive Common Eiders (Somateria mollissima (L., 1758)) fed with various mussel types to determine their impact on Eiders’ digestion. Aquacultured and small mussels were of better quality, because of higher energy content and less resistant shells. These mussel characteristics allowed faster digestive processes for an equal digestibility compared with large intertidal mussels. Previous studies showed that aquacultured and small mussels were generally preferred by sea ducks. Hence, prey-selection behaviours and digestive processes seem closely connected in these highly digestive-constrained predators.

Two methods of radio transmitter attachment and their effects on the behavior and energetics of captive long-tailed ducks (Clangula hyemalis) during winter

Attachment of external devices can have negative consequences for the health and fitness of subjects, but these effects are often overlooked. In preparation for a field study with small sea ducks, we investigated the effects of two types of external radio transmitter attachments on activity budgets and energetics of captive long-tailed ducks (Clangula hyemalis) during winter. We conducted behavioral observations on 15 ducks over 3 months and measured oxygen consumption rates while resting on water and during preening. Ducks were either sham handled (‘Control’) or had transmitters attached with subcutaneous anchors (‘Prongs’) or Tesa tape/sutures (‘Tesa’). Following transmitter attachment, the activity budgets of Prong and Tesa birds changed significantly, while Controls remained largely unchanged. Prong and Tesa birds reduced locomotor activity (−58 and −54 %, respectively) and the proportion of time spent in water (−48 and −35 %, respectively), while they concomitantly increased time allocated to maintenance behavior (+98 and +151 %, respectively). Tesa birds recovered from these changes over time, at least partially, but Prong birds did not. Also, two of the five Prong birds developed a bacterial infection that spread from the attachment site. Retention time of transmitters was significantly greater for the Prong attachments (4 of 5 tags were retained for the entire 59-day study) than the Tesa technique (26.0 ± 3.2 days). Energy metabolism of ducks resting on water did not change significantly after transmitter attachment. Preening, the primary maintenance behavior, increased oxygen consumption rates by ~70 % over resting. The greater allocation of time to maintenance behavior after transmitter attachment most likely increased daily energy expenditure in these ducks, although the concurrent reduction in locomotor activity might have mitigated this effect. Ducks in our study had food ad libitum and were able to reduce locomotion after transmitter attachment without compromising food intake and, hence, energy balance. In the wild, this strategy might not be viable. Given the short retention time, the tape-based attachment technique we applied is not suitable if monitoring periods greater than ~2 to 3 weeks are desired. Both methods resulted in significant behavioral changes with energetic consequences that should be considered when planning to attach external transmitters to small sea ducks in the wild.

Trace elements in eggs of common eiders (Somateria mollissima) breeding in Nova Scotia, Canada

We provide the first report on trace element concentrations in eggs of common eiders (Somateria mollissima), a coastal benthic foraging sea duck, from Nova Scotia, Canada, and compare those to known values from this species elsewhere. Most trace elements of toxicological concern (Hg, Se, Cd, Cu, Zn) were lower in eider eggs from Nova Scotia than from eider eggs collected farther north in Canada, although As was elevated. Our data provide strong support for a pattern of increasing Hg at higher latitudes for this species.