The Experts below are selected from a list of 1617 Experts worldwide ranked by ideXlab platform
Mikael Kilpi - One of the best experts on this subject based on the ideXlab platform.
-
declines amongst breeding eider Somateria mollissima numbers in the baltic wadden sea flyway
Ornis Fennica, 2012Co-Authors: Johan Ekroos, Karsten Laursen, Mikael Kilpi, Thomas Kjaer Christensen, Anthony D Fox, Ib Krag Petersen, Jon Einar Jonsson, Martin Green, Anja Cervencl, Peter De BoerAbstract:We report on the status of the Baltic/Wadden Sea flyway Eider population based on trends in breeding and wintering numbers throughout the region, supplemented by changes in the sex ratio and proportion of young Eiders as monitored in the Danish hunting bag. At the flyway scale, total numbers of breeding pairs decreased by 48% during 2000-2009, after relatively stable breeding numbers in 1991-2000. The majority of the population nest in Finland and Sweden, where the number of breeding pairs has halved over the same period. After initial declines in winter numbers between 1991 and 2000, during 2000-2009, national wintering numbers increased in the Baltic Sea, but decreased in the Wadden Sea. The annual proportion of adult females in the Danish hunting bag data decreased from ca. 45% (1982) to ca. 25% (2009) and simultaneously the proportion of first-winter birds fell from ca. 70% to ca. 30%, indicating dramatic structural changes in the Danish wintering numbers. These results suggest that the total flyway population will experience further declines, unless productivity increases and the factors responsible for decreasing adult female survival are identified and ameliorated. We discuss potential population drivers and present some recommendations for improved flyway-level monitoring and management of Eiders.
-
large scale change in the sex ratio of a declining eider Somateria mollissima population
Wildlife Biology, 2008Co-Authors: Aleksi Lehikoinen, Markus Ost, Mikael Kilpi, Thomas Kjaer Christensen, Pertti Saurola, Aarne VattulainenAbstract:Abstract The breeding potential of a monogamous animal population should be maximal during equal operational sex ratio, and empirical evidence suggests that the population-wide sex ratio may be linked to population density. We studied the sex ratio of eiders Somateria mollissima migrating into the Gulf of Finland, the Baltic Sea, in nine years during 1979–2005 (1979–1980, 1982–1983 and 2001–2005), and the sex ratio of birds collected by Danish hunters during 1982–2004. In two decades, the sex ratio during peak migration has reversed from female bias to male bias, and hunting statistics have shown a significantly increasing adult male bias. Also the proportion of juvenile males has shown a significant increase (Danish hunting statistics 1982–2004), which indicates either that the primary sex ratio of ducklings is exceedingly male biased, or that the mortality of female ducklings has increased. This shift in sex ratio is paralleled by a dramatic decrease in the Baltic eider population which started in the e...
-
does sex specific duckling mortality contribute to male bias in adult common eiders
The Condor, 2008Co-Authors: Aleksi Lehikoinen, Markus Ost, Tuula E Hollmen, Mikael KilpiAbstract:Abstract Adult sex ratios of waterfowl often show male bias, usually explained by differential female mortality during breeding. However, the sex ratio among first-winter Common Eiders (Somateria mollissima) in Europe is already male biased; thus, the breeding mortality hypothesis cannot be the sole explanation for this phenomenon. To clarify when the observed male bias originally arises, we studied the sex ratio of hatched eider ducklings and the sex ratio of ducklings found dead prior to fledging in a wild and free-ranging population. The hatching sex ratio did not deviate from equal (50% females, n = 418). In contrast, the sex ratio of duckling carcasses was female biased (59%, n = 118), suggesting that survival of female ducklings is lower than that of males. Consequently, the adult-male bias found in many ducks may be established already during the early phases of life, despite an equal sex ratio at hatching.
-
social and maternal factors affecting duckling survival in eiders Somateria mollissima
Journal of Animal Ecology, 2008Co-Authors: Markus Ost, Barry D Smith, Mikael KilpiAbstract:1. With the aid of a novel survivorship model, an 8-year field study of social and maternal factors affecting duckling survival in eiders (Somateria mollissima) revealed that duckling survival probability varies in accordance with maternal brood-rearing strategy. This variability in survival provides compelling evidence of different annual fitness consequences between females that share brood-rearing and those that tend their broods alone. Consequently, as prebreeding survival is often a major source of individual variation in lifetime reproductive success, a female's annual, state-dependent (e.g. condition) choice of a brood-rearing strategy can be a critical fitness decision. 2. Variance in duckling survival among lone tender broods was best explained by a model with significant interannual variability in survival, and survivorship tending to increase with increasing clutch size at hatch. Clutch size was correlated positively with female condition. Hatch date and female body condition together affected duckling survival, but their contributions are confounded. We were unable to identify a relationship between female age or experience and duckling survival. 3. Variance in duckling survival among multifemale brood-rearing coalitions was best explained by a model that included the number of tenders, the number of ducklings and interannual variation in how their ratio affected survivorship. Hatch date did not significantly influence survival. 4. Expected duckling survival is higher in early life for lone tenders when compared with multifemale brood-rearing coalitions. However, as ducklings approach 2-3 weeks of age, two or three females was the optimal number of tenders to maximize daily duckling survival. The survivorship advantage of multifemale brood-rearing coalitions was most evident in years of average survival. 5. The observed frequency distribution of female group sizes corresponds with the distribution of offspring survival probabilities for these groups. Evidence for optimal group sizes in nature is rare, but the most likely candidates may be groups of unrelated animals where entry is controlled by the group members, such as for female eiders. 6. Our study demonstrates that differences in social factors can lead to different predictions of lifetime reproductive success in species with shared parental care of self-feeding young.
-
evidence of chromosomal damage in common eiders Somateria mollissima from the baltic sea
Marine Pollution Bulletin, 2004Co-Authors: Cole W Matson, Mikael Kilpi, Tuula E Hollmen, Paul L. Flint, Christian J. Franson, Martti Hario, John W BickhamAbstract:Common eiders nesting in the Baltic Sea are exposed to generally high levels of contaminants including potentially genotoxic polycyclic aromatic hydrocarbons and organochlorines. Blood samples were collected from eiders at eight sites in the Baltic Sea and two sites in the Beaufort Sea. DNA content variation was estimated using the flow cytometric method, and subsequently utilized as a biomarker of genetic damage. We observed no significant differences in genetic damage among populations within either the Baltic or Beaufort Seas. However, eider populations from the Baltic Sea had significantly elevated estimates of genetic damage compared to populations from the Beaufort Sea.
Anders Pape Moller - One of the best experts on this subject based on the ideXlab platform.
-
large feet are beneficial for eiders Somateria mollissima
Ecology and Evolution, 2019Co-Authors: Anders Pape Moller, Karsten LaursenAbstract:Many waterbirds have fully (totipalmate) or partially webbed (palmate) feet that are used for locomotion in aquatic environments.If webbed feet and wings both contribute to efficient diving, we predicted a positive association between the area of webbed feet and the size of the frontal locomotor apparatus (wing area, heart mass, and breast muscle, after adjusting for any partial effects of body size). We predicted that individuals able to acquire more and better quality food due to larger webbed feet should have larger livers with higher concentrations of fat-soluble antioxidants such as vitamin E, and invest more in immune function as reflected by the relative size of the uropygial gland than individuals with small webbed feet.Here, we examine if the area of webbed feet is correlated with locomotion, diet, and body condition in a sea-duck, the eider (Somateria mollissima). We analyzed an extensive database of 233 eiders shot in Danish waters and at Aland, Finland during winter and early spring.Eiders with larger webbed feet had a larger locomotor apparatus, but did not have larger body size, they had larger uropygial glands that waterproof the plumage, they had larger beak volume and larger gizzards, and they had higher body condition.These findings imply that eiders with large webbed feet benefitted in terms of locomotion, feeding, and reproduction.
-
Function of the uropygial gland in eiders (Somateria mollissima)
Avian Research, 2019Co-Authors: Anders Pape Moller, Karsten LaursenAbstract:The uropygial gland is an exocrine gland located above the tail of birds that produces a diverse range of biochemicals. It has been hypothesized to be involved in chemical protection, water-proofing and maintenance of plumage brightness. Although these not necessarily mutually exclusive functions have received some empirical support, there has been little empirical research on the function of water-proofing. Here we analyzed data for 229 individual eiders (Somateria mollissima) collected by Danish hunters during 2016‒2018. The Eider is a sea-duck that spends almost its entire life in sea water emphasizing water-proofing of the plumage. The size of the uropygial gland increased with body mass in males, but not in females, and it increased with age. The size of the uropygial gland decreased during winter. Eiders with small uropygial glands grew their feathers at a fast rate. Eiders with large wing areas had large uropygial glands. These findings are consistent with large uropygial glands playing a role in water-proofing during molt and foraging, but also that uropygial glands may play a role in chemical defense.
-
dynamic group size and displacement as avoidance strategies by eiders in response to hunting
Wildlife Biology, 2016Co-Authors: Karsten Laursen, Anders Pape Moller, Thomas Eske HolmAbstract:Hunting by humans constitutes a major source of mortality that selects for avoidance strategies. Group formation in eiders Somateria mollissima in response to hunting from motorboats was studied in the Danish Wadden Sea as an avoidance strategy to humans. In autumn the birds' food demand and energy consumption are relatively low and the need for optimal feeding opportunities are not as essential as during winter. We tested the hypothesis that eiders aggregate in groups of variable size dependent on predation risk (hunting), season and site. During autumn at the preferred feeding sites eiders occur in small numbers and group size increase together with hunting activity. Opposite during winter, eiders occur in large numbers and group size decrease when hunting activity increase. Hunting activity displaced eiders to adjacent sites with no or low hunting intensity and low food availability where group size of eiders increase during both autumn and winter in relation to the overall hunting activity. The format...
-
long term changes in nutrients and mussel stocks are related to numbers of breeding eiders Somateria mollissima at a large baltic colony
PLOS ONE, 2014Co-Authors: Karsten Laursen, Anders Pape MollerAbstract:Background The Baltic/Wadden Sea eider Somateria mollissima flyway population is decreasing, and this trend is also reflected in the large eider colony at Christianso situated in the Baltic Sea. This colony showed a 15-fold increase from 1925 until the mid-1990's, followed by a rapid decline in recent years, although the causes of this trend remain unknown. Most birds from the colony winter in the Wadden Sea, from which environmental data and information on the size of the main diet, the mussel Mytilus edulis stock exists. We hypothesised that changes in nutrients and water temperature in the Wadden Sea had an effect on the ecosystem affecting the size of mussel stocks, the principal food item for eiders, thereby influencing the number of breeding eider in the Christianso colony.
Sundsvold Bente - One of the best experts on this subject based on the ideXlab platform.
-
"Å tenkje som en fauel" Med videokamera i utforskning av relasjonsbygging og meningsdannelse mellom menneske og fugl
'Scandinavian University Press Universitetsforlaget AS', 2018Co-Authors: Sundsvold BenteAbstract:The following article, Sundsvold, B. (2018). "Å tenkje som en fauel" Med videokamera i utforskning av relasjonsbygging og meningsdannelse mellom menneske og fugl. Norsk Antropologisk Tidsskrift, 29(3-4), 179-198, can be accessed at https://doi.org/10.18261/issn.1504-2898-2018-03-04-06.I artikkelen undersøkes hvordan bruken av videokamera i feltarbeidssituasjonen kan bidra til å utforske og utvikle tilnærminger til relasjonsbyggingen mellom to ulike arter, menneske og fugl. Empirien er hentet fra ærfuglrøkt på Helgelandskysten, og til en kvinnes arbeid med å bygge opp et nedlagt egg- og dunvær. Hun skal venne ville ærfugler (Somateria mollissima) til mennesker, bygge opp en ny stamme av «tamme» ærfugler. Forfatteren har fulgt henne med videokamera i dette arbeidet, som kan forstås som et eto-/etnografisk feltarbeid, hvor fuglenes bevegelser og handlinger har vært like viktige å forstå som menneskets. Gjennom videoopptakene studeres situasjoner som kan gi inntak til meningsproduksjon mellom to arter som verken deler språk, persepsjon eller element. Ritualteori, performativitet og Kohns bruk av «semiosis» er teoretiske tilnærminger i disse undersøkelsene.English abstract The article seeks to explore the potential of using video footage in approaching inter-species communication and interaction. The empirical field is eider down harvesting practice on the coast of Helgeland, in particular the work of rebuilding an abandoned eider rookery and adjusting wild eider ducks (Somateria mollissima) to humans. In this work, the birds play a key role, and the fieldwork approach may be understood as etho-ethnography, where human and birds gets equal attention. By use of the video footage, the author tries to understand how meaning is established between the two species, which neither share language, perceptions nor elements. Ritual theory, performativity and Kohn’s «semiosis» are theoretical approaches in order to explore an anthropology beyond the human.
-
"Å tenkje som en fauel" Med videokamera i utforskning av relasjonsbygging og meningsdannelse mellom menneske og fugl
'Scandinavian University Press Universitetsforlaget AS', 2018Co-Authors: Sundsvold BenteAbstract:I artikkelen undersøkes hvordan bruken av videokamera i feltarbeidssituasjonen kan bidra til å utforske og utvikle tilnærminger til relasjonsbyggingen mellom to ulike arter, menneske og fugl. Empirien er hentet fra ærfuglrøkt på Helgelandskysten, og til en kvinnes arbeid med å bygge opp et nedlagt egg- og dunvær. Hun skal venne ville ærfugler (Somateria mollissima) til mennesker, bygge opp en ny stamme av «tamme» ærfugler. Forfatteren har fulgt henne med videokamera i dette arbeidet, som kan forstås som et eto-/etnografisk feltarbeid, hvor fuglenes bevegelser og handlinger har vært like viktige å forstå som menneskets. Gjennom videoopptakene studeres situasjoner som kan gi inntak til meningsproduksjon mellom to arter som verken deler språk, persepsjon eller element. Ritualteori, performativitet og Kohns bruk av «semiosis» er teoretiske tilnærminger i disse undersøkelsene
Karsten Laursen - One of the best experts on this subject based on the ideXlab platform.
-
large feet are beneficial for eiders Somateria mollissima
Ecology and Evolution, 2019Co-Authors: Anders Pape Moller, Karsten LaursenAbstract:Many waterbirds have fully (totipalmate) or partially webbed (palmate) feet that are used for locomotion in aquatic environments.If webbed feet and wings both contribute to efficient diving, we predicted a positive association between the area of webbed feet and the size of the frontal locomotor apparatus (wing area, heart mass, and breast muscle, after adjusting for any partial effects of body size). We predicted that individuals able to acquire more and better quality food due to larger webbed feet should have larger livers with higher concentrations of fat-soluble antioxidants such as vitamin E, and invest more in immune function as reflected by the relative size of the uropygial gland than individuals with small webbed feet.Here, we examine if the area of webbed feet is correlated with locomotion, diet, and body condition in a sea-duck, the eider (Somateria mollissima). We analyzed an extensive database of 233 eiders shot in Danish waters and at Aland, Finland during winter and early spring.Eiders with larger webbed feet had a larger locomotor apparatus, but did not have larger body size, they had larger uropygial glands that waterproof the plumage, they had larger beak volume and larger gizzards, and they had higher body condition.These findings imply that eiders with large webbed feet benefitted in terms of locomotion, feeding, and reproduction.
-
Function of the uropygial gland in eiders (Somateria mollissima)
Avian Research, 2019Co-Authors: Anders Pape Moller, Karsten LaursenAbstract:The uropygial gland is an exocrine gland located above the tail of birds that produces a diverse range of biochemicals. It has been hypothesized to be involved in chemical protection, water-proofing and maintenance of plumage brightness. Although these not necessarily mutually exclusive functions have received some empirical support, there has been little empirical research on the function of water-proofing. Here we analyzed data for 229 individual eiders (Somateria mollissima) collected by Danish hunters during 2016‒2018. The Eider is a sea-duck that spends almost its entire life in sea water emphasizing water-proofing of the plumage. The size of the uropygial gland increased with body mass in males, but not in females, and it increased with age. The size of the uropygial gland decreased during winter. Eiders with small uropygial glands grew their feathers at a fast rate. Eiders with large wing areas had large uropygial glands. These findings are consistent with large uropygial glands playing a role in water-proofing during molt and foraging, but also that uropygial glands may play a role in chemical defense.
-
dynamic group size and displacement as avoidance strategies by eiders in response to hunting
Wildlife Biology, 2016Co-Authors: Karsten Laursen, Anders Pape Moller, Thomas Eske HolmAbstract:Hunting by humans constitutes a major source of mortality that selects for avoidance strategies. Group formation in eiders Somateria mollissima in response to hunting from motorboats was studied in the Danish Wadden Sea as an avoidance strategy to humans. In autumn the birds' food demand and energy consumption are relatively low and the need for optimal feeding opportunities are not as essential as during winter. We tested the hypothesis that eiders aggregate in groups of variable size dependent on predation risk (hunting), season and site. During autumn at the preferred feeding sites eiders occur in small numbers and group size increase together with hunting activity. Opposite during winter, eiders occur in large numbers and group size decrease when hunting activity increase. Hunting activity displaced eiders to adjacent sites with no or low hunting intensity and low food availability where group size of eiders increase during both autumn and winter in relation to the overall hunting activity. The format...
-
long term changes in nutrients and mussel stocks are related to numbers of breeding eiders Somateria mollissima at a large baltic colony
PLOS ONE, 2014Co-Authors: Karsten Laursen, Anders Pape MollerAbstract:Background The Baltic/Wadden Sea eider Somateria mollissima flyway population is decreasing, and this trend is also reflected in the large eider colony at Christianso situated in the Baltic Sea. This colony showed a 15-fold increase from 1925 until the mid-1990's, followed by a rapid decline in recent years, although the causes of this trend remain unknown. Most birds from the colony winter in the Wadden Sea, from which environmental data and information on the size of the main diet, the mussel Mytilus edulis stock exists. We hypothesised that changes in nutrients and water temperature in the Wadden Sea had an effect on the ecosystem affecting the size of mussel stocks, the principal food item for eiders, thereby influencing the number of breeding eider in the Christianso colony.
-
declines amongst breeding eider Somateria mollissima numbers in the baltic wadden sea flyway
Ornis Fennica, 2012Co-Authors: Johan Ekroos, Karsten Laursen, Mikael Kilpi, Thomas Kjaer Christensen, Anthony D Fox, Ib Krag Petersen, Jon Einar Jonsson, Martin Green, Anja Cervencl, Peter De BoerAbstract:We report on the status of the Baltic/Wadden Sea flyway Eider population based on trends in breeding and wintering numbers throughout the region, supplemented by changes in the sex ratio and proportion of young Eiders as monitored in the Danish hunting bag. At the flyway scale, total numbers of breeding pairs decreased by 48% during 2000-2009, after relatively stable breeding numbers in 1991-2000. The majority of the population nest in Finland and Sweden, where the number of breeding pairs has halved over the same period. After initial declines in winter numbers between 1991 and 2000, during 2000-2009, national wintering numbers increased in the Baltic Sea, but decreased in the Wadden Sea. The annual proportion of adult females in the Danish hunting bag data decreased from ca. 45% (1982) to ca. 25% (2009) and simultaneously the proportion of first-winter birds fell from ca. 70% to ca. 30%, indicating dramatic structural changes in the Danish wintering numbers. These results suggest that the total flyway population will experience further declines, unless productivity increases and the factors responsible for decreasing adult female survival are identified and ameliorated. We discuss potential population drivers and present some recommendations for improved flyway-level monitoring and management of Eiders.
Mark L Mallory - One of the best experts on this subject based on the ideXlab platform.
-
annual movement patterns of american common eiders Somateria mollissima dresseri
Wildlife Biology, 2020Co-Authors: Mark L Mallory, Randy G Milton, Chris Dwyer, Robert A Ronconi, Bradford R Allen, Stephane Lair, Conor D Mallory, Nic R Mclellan, Glen J Parsons, Lucas SavoyAbstract:The American common eider Somateria mollissima dresseri is a sea duck of coastal mid-Atlantic North America, and breeding colonies in the southern part of its range have been in decline. To better understand threats faced by the subspecies, we used satellite telemetry to track 46 eiders through their annual cycle in four years from three regions in the southern part of the range, to identify key locations and migratory corridors. Female eiders exhibited highly variable movement phenology within and among colonies, but coastal Maine and Massachusetts were consistent, important moulting areas for males and females from all breeding colonies. Most birds wintered in coastal waters around Cape Cod and Nantucket Sound, meaning that threats in this region (industrial development, disease outbreak, harvest) could have deleterious effects on much of the population.
-
Aggressive neighbors and dense nesting: nest site choice and success in high-Arctic common eiders
Polar Biology, 2016Co-Authors: Isabeau Pratte, M. Maftei, S. E. Davis, Mark L MalloryAbstract:Minimizing the risk of nest predation has led some bird species to exploit the nest defense behavior of other species. At Nasaruvaalik Island, Nunavut, Canada, some common eiders ( Somateria mollissima borealis ) nest within the boundaries of Arctic tern ( Sterna paradisaea ) colonies, while others nest elsewhere on the island, away from the terns. We tested the effects of location (within vs. outside the tern colonies), density of common eider nests, and annual variation on the nesting parameters of common eiders. Our results suggest that nesting in association with Arctic terns does not confer an obvious benefit to eiders. Such associative nesting of eiders and terns may be the result of overlapping habitat preferences between the two species, or a general scarcity of suitable nesting habitat for ground-nesting species in the high Arctic. However, eiders nesting in higher densities with other eiders had greater nest success and lower total clutch predation, indicating a positive correlation between nest density and success.
-
trace elements in eggs of common eiders Somateria mollissima breeding in nova scotia canada
Marine Pollution Bulletin, 2015Co-Authors: Isabeau Pratte, Molly D Tomlik, Randy G Milton, Taylor A Betsch, Birgit M Braune, Mark L MalloryAbstract: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.
-
colonial marine birds influence island soil chemistry through biotransport of trace elements
Water Air and Soil Pollution, 2015Co-Authors: Mark L Mallory, Lewis Mahon, Molly D Tomlik, Christopher D White, Randy G Milton, Ian SpoonerAbstract:Marine birds are important vectors of nutrient and contaminant transfer from sea to land. In eastern Nova Scotia, Canada, colonial marine birds nest on specific nearshore islands within archipelagoes, and we predicted that soils on islands with bird colonies would have higher concentrations of selected trace elements (notably K, Ca, As, Cd, Cu, Pb, Se, Hg, and Zn) than soils on islands without colonies. In this study, common eider (Somateria mollissima), Leach’s storm petrel (Oceanodroma leucorhoa), black guillemot (Cepphus grylle), double-crested cormorant (Phalacrocorax auritus), great black-backed gull (Larus marinus), and herring gull (Larus argentatus) were considered to be the principal avian vectors for contaminant transfer. Results indicate that soils from islands with bird colonies had unique chemical compositions and commonly displayed elevated concentrations of K, Ca, Cu, Se, and Zn when compared to islands without colonies. Thus, marine birds feeding in the nearby marine zone move pollutants and nutrients from the ocean to nesting islands, potentially influencing habitat quality for coastal terrestrial species.
-
Assessing regional populations of ground-nesting marine birds in the Canadian High Arctic
Norwegian Polar Institute, 2015Co-Authors: M. Maftei, S. E. Davis, Mark L MalloryAbstract:The Queens Channel region of Nunavut is an ecologically distinct area within the Canadian High Arctic consisting of an extensive archipelago of small, low-lying gravel islands throughout which form several localized but highly productive polynyas. We used aerial survey and colony-monitoring data to assess regional- and colony-level fluctuations in the number of birds in this region between 2002 and 2013. Regional and colony-specific monitoring suggested that common eider (Somateria mollissima) numbers are increasing, while numbers of Arctic terns (Sterna paradisaea) may be in decline. Based on these data, we suggest that even infrequent comprehensive surveys are more useful than annual monitoring at specific sites in generating an accurate assessment of ground-nesting seabird populations at the regional level, and that dramatic fluctuations at individual colonies probably belie the overall stability of regional populations
