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Copyright of Ornithological Applications is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The common snipe (Gallinago gallinago) is a wader that breeds in subarctic regions from Iceland to Russia, and for which global populations are in decline. We studied snipe breeding in western Iceland between 1998 and 2020, locating nests and ringing birds annually. In 2019 and 2020, we deployed geolocators on nesting adults to estimate the timing of their annual migration and the location of overwintering areas. Birds moved principally between breeding locations in Iceland to wintering areas in Ireland, although some birds may winter farther north. We also found that apparent annual adult survival averaged 66%, but was higher in years with warmer, wetter winters. Given the similarity of our survival estimates to those from snipe elsewhere, we suggest that adult survival is unlikely a major contributor to declining populations, and other factors like habitat loss may be of more concern. [ABSTRACT FROM AUTHOR]

Migratory species have geographically separate distributions during their annual cycle, and these areas can vary between populations and individuals. This can lead to differential stress levels being experienced across a species range. Gathering information on the areas used during the annual cycle of red‐throated divers (RTDs; Gavia stellata) has become an increasingly pressing issue, as they are a species of concern when considering the effects of disturbance from offshore wind farms and the associated ship traffic. Here, we use light‐based geolocator tags, deployed during the summer breeding season, to determine the non‐breeding winter location of RTDs from breeding locations in Scotland, Finland, and Iceland. We also use δ15N and δ13C isotope signatures, from feather samples, to link population‐level differences in areas used in the molt period to population‐level differences in isotope signatures. We found from geolocator data that RTDs from the three different breeding locations did not overlap in their winter distributions. Differences in isotope signatures suggested this spatial separation was also evident in the molting period, when geolocation data were unavailable. We also found that of the three populations, RTDs breeding in Iceland moved the shortest distance from their breeding grounds to their wintering grounds. In contrast, RTDs breeding in Finland moved the furthest, with a westward migration from the Baltic into the southern North Sea. Overall, these results suggest that RTDs breeding in Finland are likely to encounter anthropogenic activity during the winter period, where they currently overlap with areas of future planned developments. Icelandic and Scottish birds are less likely to be affected, due to less ship activity and few or no offshore wind farms in their wintering distributions. We also demonstrate that separating the three populations isotopically is possible and suggest further work to allocate breeding individuals to wintering areas based solely on feather samples. [ABSTRACT FROM AUTHOR]

This study aims to determine the level of movement of individuals between the Icelandic and Northwest Mainland European (NWME) Whooper Swan Cygnus cygnus populations, and to assess the extent to which this interchange affects total population estimates. Ringing, resighting and recovery data for Whooper Swans ringed across Europe since the early 1900s were compiled from the EURING Data Bank, national ringing schemes and individual ringers. Birds were assigned to the biogeographical population (Icelandic or NWME) in which they were ringed. Of >18 000 Whooper Swans ringed in 17 European countries, 172 individuals (0.94%) were later found outside the nominal range of their assigned biogeographical population. The proportion of ringed swans from the Icelandic population that were subsequently found 'out of range' did not differ significantly from the proportion recorded for the NWME population, indicating no directional bias in population interchange. Population switching by Whooper Swans in western Europe occurs consistently, but currently at very low levels. Our results reinforce the view that such levels of population interchange are unlikely to have caused major inaccuracies or biases in the total numbers recorded during the coordinated censuses used to estimate population size. [ABSTRACT FROM AUTHOR]

Identifying temporal and spatial patterns in demography is critical to understanding long‐term fluctuations in population size. Common Eider Somateria mollissima numbers have shown a long‐term decline, resulting in the species being uplisted in 2015 to 'Endangered' within European Union countries. Obtaining improved estimates of survival rates of Common Eiders (and other seaducks) has been identified as a priority to improve our understanding of the demographic causes of the observed global decreases in population size and to inform conservation efforts. In this study, we used long‐term (1982–2017) mark–recovery data on 3018 individuals from three breeding colonies in Iceland to quantify the spatial and temporal variation in the annual true survival rates of adult female Common Eider. Model comparison using an information‐theoretic approach indicated that true survival and recovery rates varied between years and colonies but showed no consistent temporal pattern across the three colonies. Geometric mean (± se) annual true survival across our three breeding colonies was 0.916 ± 0.017 (95% confidence interval (CI) = 0.819–0.961), with a mean life expectancy of 11.8 years (95% CI 5.4–25.2). Our survival estimates were relatively high compared with those reported previously for many other Common Eider populations, which may reflect their protected status, low predation pressure and high food availability on Iceland and its surrounding waters. Our findings provide spatially and temporally explicit demographic information needed to help conservationists understand the local and global declines in Common Eider populations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ornithology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many seabird species in the North Atlantic region have shown considerable declines in their populations during recent decades. One such species is the Arctic tern (Sterna paradisaea), a small seabird which migrates farther than any other seabird each year and whose global population is thought to be in decline. We used banding data of chicks and adults, spanning five decades (1974–2017) from a tern colony on Flatey, in western Iceland, to generate the first assessment of annual survival in this species in Iceland. Survival from just after hatching to the next summer was estimated to be 0.119 ± 0.024 (SE), while annual survival of adult birds (older than one year) was high at 0.952 ± 0.030. Although our data were insufficient to assess annual variation in adult survival, we noted a reduced survival (0.851 ± 0.034) in recent years (since 2000), coincident with a collapse in local sand lance populations. Reduced adult survival, along with other factors, is likely contributing to declining populations of this iconic species in Iceland, a country supporting 20–30% of the world's breeding population. [ABSTRACT FROM AUTHOR]

There is a growing body of evidence demonstrating the impacts of human arrival in new "pristine" environments, including terrestrial habitat alterations and species extinctions. However, the effects of marine resource utilization prior to industrialized whaling, sealing, and fishing have largely remained understudied. The expansion of the Norse across the North Atlantic offers a rare opportunity to study the effects of human arrival and early exploitation of marine resources. Today, there is no local population of walruses on Iceland, however, skeletal remains, place names, and written sources suggest that walruses existed, and were hunted by the Norse during the Settlement and Commonwealth periods (870–1262 AD). This study investigates the timing, geographic distribution, and genetic identity of walruses in Iceland by combining historical information, place names, radiocarbon dating, and genomic analyses. The results support a genetically distinct, local population of walruses that went extinct shortly after Norse settlement. The high value of walrus products such as ivory on international markets likely led to intense hunting pressure, which—potentially exacerbated by a warming climate and volcanism—resulted in the extinction of walrus on Iceland. We show that commercial hunting, economic incentives, and trade networks as early as the Viking Age were of sufficient scale and intensity to result in significant, irreversible ecological impacts on the marine environment. This is to one of the earliest examples of local extinction of a marine species following human arrival, during the very beginning of commercial marine exploitation. [ABSTRACT FROM AUTHOR]

Background: In the North Pacific, northern fulmar (Fulmarus glacialis) forms extensive colonies in few locales, which may lead to limited gene flow and locale-specific population threats. In the Atlantic, there are thousands of colonies of varying sizes and in Europe the species is considered threatened. Prior screens and classical microsatellite development in fulmar failed to provide a suite of markers adequate for population genetics studies. Objectives: The objective of this study was to isolate a suite of polymorphic microsatellite loci with sufficient variability to quantify levels of gene flow, population affinity, and identify familial relationships in fulmar. We also performed a cross-species screening of these markers in eight other species. Methods: We used shotgun sequencing to isolate 26 novel microsatellite markers in fulmar to screen for variability using individuals from two distinct regions: the Pacific (Chagulak Island, Alaska) and the Atlantic (Hafnarey Island, Iceland). Results: Polymorphism was present in 24 loci in Chagulak and 23 in Hafnarey, while one locus failed to amplify in either colony. Polymorphic loci exhibited moderate levels of genetic diversity and this suite of loci uncovered genetic structuring between the regions. Among the other species screened, polymorphism was present in one to seven loci. Conclusion: The loci yielded sufficient variability for use in population studies and estimation of familial relationships; as few as five loci provide resolution to determine individual identity. These markers will allow further insight into the global population dynamics and phylogeography of fulmars. We also demonstrated some markers are transferable to other species. [ABSTRACT FROM AUTHOR]

Global warming is a nonlinear process, and temperature may increase in a stepwise manner. Periods of abrupt warming can trigger persistent changes in the state of ecosystems, also called regime shifts. The responses of organisms to abrupt warming and associated regime shifts can be unlike responses to periods of slow or moderate change. Understanding of nonlinearity in the biological responses to climate warming is needed to assess the consequences of ongoing climate change. Here, we demonstrate that the population dynamics of a long-lived, wide-ranging marine predator are associated with changes in the rate of ocean warming. Data from 556 colonies of black-legged kittiwakes Rissa tridactyla distributed throughout its breeding range revealed that an abrupt warming of sea-surface temperature in the 1990s coincided with steep kittiwake population decline. Periods of moderate warming in sea temperatures did not seem to affect kittiwake dynamics. The rapid warming observed in the 1990s may have driven large-scale, circumpolar marine ecosystem shifts that strongly affected kittiwakes through bottom-up effects. Our study sheds light on the nonlinear response of a circumpolar seabird to large-scale changes in oceanographic conditions and indicates that marine top predators may be more sensitive to the rate of ocean warming rather than to warming itself. [ABSTRACT FROM AUTHOR]

Environmental contaminants may have impacts on reproduction and survival in wildlife populations suffering from multiple stressors. This study examined whether adverse effects of persistent organic pollutants (POPs) increased with poor population health and breeding conditions in three colonies (60–74°N) of great skua (Stercorarius skua) in the north-eastern Atlantic (Shetland, Iceland and Bjørnøya [Bear Island]). POPs (organochlorines [OCs] and polybrominated diphenyl ethers [BDEs]) were measured in plasma of incubating birds (n = 222), concentrations differing nearly tenfold among colonies: Bjørnøya (2009) > Bjørnøya (2010) > Iceland (2009) > Shetland (2009). Reproductive success (hatching success and chick survival) showed that breeding conditions were favourable in Shetland and at Bjørnøya (2010), but were very poor in Iceland and at Bjørnøya (2009). Biomarkers indicated that health was poor in the Shetland population compared to the other populations. Females whose chicks hatched late had high POP concentrations in all colonies except at Bjørnøya (2010), and females losing their eggs at Bjørnøya (2009) tended to have higher concentrations than those hatching. Moreover, there was a negative relationship between female POP concentrations and chick body condition at hatching in Iceland and at Bjørnøya (2010). Supplementary feeding experiments were conducted, and in Iceland where feeding conditions were poor, significant negative relationships were found between female POP concentrations and daily growth-rate in first-hatched chicks of control nests, but not in food supplemented nests. This suggests that negative impacts of POPs were mitigated by improved feeding conditions. For second-chicks, there was a strong negative relationship between the female POP concentrations and growth-rate, but no effects of supplementary feeding. Lowered adult return-rate between breeding seasons with increasing POP loads were found both at Bjørnøya (2009) and in Shetland, especially related to BDEs. This indicates stronger fitness consequences of POPs following seasons with very poor breeding conditions and/or high reproductive effort. This study suggests that the impacts of POPs may differ depending on population health and breeding conditions, and that even low concentrations of POPs could have ecological consequences during adverse circumstances. This is important with regard to risk assessment of biomagnifying contaminants in marine ecosystems. [ABSTRACT FROM AUTHOR]

CapsuleGreat SkuasStercorarius skuawintering in different areas spent different amounts of time in flight (foraging or searching for food) and so may be experiencing different feeding conditions. AimsTo compare the daily percentage of time spent in flight (foraging or searching for food) between different wintering areas. MethodsIn 2008, loggers equipped with a saltwater sensor were deployed on adult Great Skuas at three colonies in the northeast Atlantic, and the data used to compare foraging activity between the five main wintering areas. ResultsThe five areas used by 22 Great Skuas in winter were widely separated, from the northwest Atlantic to northwest Africa, and differ substantially in oceanography. The main difference in foraging effort among areas for individuals that were site-faithful was that the percentage of time per day spent in flight off northwest Africa was much lower than elsewhere. Among five birds that travelled between wintering areas, one reduced the percentage of time in flight after switching from Iberia to northwest Africa. ConclusionThe data suggest that feeding conditions were better off northwest Africa than elsewhere, at least during winter 2008/09. This allowed Great Skuas wintering in that region to spend more time resting, so probably reducing their overall energy expenditure. [ABSTRACT FROM AUTHOR]

Environmental conditions encountered by migratory seabirds in their wintering areas can shape their fitness. However, the underlying physiological mechanisms remain largely unknown as birds are relatively inaccessible during winter. To assess physiological condition during this period, we measured corticosterone concentrations in winter-grown primary feathers of female great skuas (Stercorarius skua) from three breeding colonies (Bjørnøya, Iceland, Shetland) with wintering areas identified from characteristic stable isotope signatures. We subsequently compared winter feather corticosterone levels between three wintering areas (Africa, Europe and America). Among females breeding in 2009, we found significant differences in feather corticosterone levels between wintering areas. Surprisingly, levels were significantly higher in Africa despite seemingly better local ecological factors (based on lower foraging effort). Moreover, contrary to our predictions, females sharing the same wintering grounds showed significant differences in feather corticosterone levels depending on their colony of origin suggesting that some skuas could be using suboptimal wintering areas. Among females wintering in Africa, Shetland females showed feather corticosterone levels on average 22% lower than Bjørnøya and Iceland females. Finally, the lack of significant relationships between winter feather corticosterone levels and any of the breeding phenology traits does not support the hypothesis of potential carry-over effects of winter feather corticosterone. Yet, the fitness consequences of elevated feather corticosterone levels remain to be determined. [ABSTRACT FROM AUTHOR]

Effects of local weather on individuals and populations are key drivers of wildlife responses to climatic changes. However, studies often do not last long enough to identify weather conditions that influence demographic processes, or to capture rare but extreme weather events at appropriate scales. In Iceland, farmers collect nest down of wild common eider Somateria mollissima and many farmers count nests within colonies annually, which reflects annual variation in the number of breeding females. We collated these data for 17 colonies. Synchrony in breeding numbers was generally low between colonies. We evaluated 1) demographic relationships with weather in nesting colonies of common eider across Iceland during 1900–2007; and 2) impacts of episodic weather events (aberrantly cold seasons or years) on subsequent breeding numbers. Except for episodic events, breeding numbers within a colony generally had no relationship to local weather conditions in the preceding year. However, common eider are sexually mature at 2–3 years of age and we found a 3-year time lag between summer weather and breeding numbers for three colonies, indicating a positive effect of higher pressure, drier summers for one colony, and a negative effect of warmer, calmer summers for two colonies. These findings may represent weather effects on duckling production and subsequent recruitment. Weather effects were mostly limited to a few aberrant years causing reductions in breeding numbers, i.e. declines in several colonies followed severe winters (1918) and some years with high NAO (1992, 1995). In terms of life history, adult survival generally is high and stable and probably only markedly affected by inclement weather or aberrantly bad years. Conversely, breeding propensity of adults and duckling production probably do respond more to annual weather variations; i.e. unfavorable winter conditions for adults increase probability of death or skipped breeding, whereas favorable summers can promote boom years for recruitment. [ABSTRACT FROM AUTHOR]

Capsule Great Skuas Stercorarius skua breeding in Scotland, Iceland, and Norway, winter in different areas. Aims To assess the winter distribution of adult Great Skuas breeding in different countries. Methods Geolocation data-loggers were deployed on breeding adults at colonies in Shetland (Scotland), southeast Iceland, and Bjørnøya (Norway) in 2008. Loggers were recovered when birds returned to breed the next year and downloaded data were processed to indicate the location of each individual throughout the winter period. Results Adult Great Skuas from Scotland wintered off northwest Africa and southern Europe. Adults from Iceland mostly wintered off Canada, with small numbers visiting northwest Africa and Europe. Although adults from Bjørnøya (Norway) migrated to similar areas to birds from Iceland, a slightly greater proportion wintered off Europe, and most used areas further north than birds from Scotland. Although three birds studied over consecutive winters used the same small area in consecutive years, four moved between different areas within one winter. Conclusion Great Skuas show clear variation in migrations among breeding regions, and some evidence of individual consistency. [ABSTRACT FROM AUTHOR]

Intraspecific brood parasitism (IBP) is a remarkable phenomenon by which parasitic females can increase their reproductive output by laying eggs in conspecific females' nests in addition to incubating eggs in their own nest. Kin selection could explain the tolerance, or even the selective advantage, of IBP, but different models of IBP based on game theory yield contradicting predictions. Our analyses of seven polymorphic autosomal microsatellites in two eider duck colonies indicate that relatedness between host and parasitizing females is significantly higher than the background relatedness within the colony. This result is unlikely to be a by-product of relatives nesting in close vicinity, as nest distance and genetic identity are not correlated. For eider females that had been ring-marked during the decades prior to our study, our analyses indicate that (i) the average age of parasitized females is higher than the age of nonparasitized females, (ii) the percentage of nests with alien eggs increases with the age of nesting females, (iii) the level of IBP increases with the host females' age, and (iv) the number of own eggs in the nest of parasitized females significantly decreases with age. IBP may allow those older females unable to produce as many eggs as they can incubate to gain indirect fitness without impairing their direct fitness: genetically related females specialize in their energy allocation, with young females producing more eggs than they can incubate and entrusting these to their older relatives. Intraspecific brood parasitism in ducks may constitute cooperation among generations of closely related females. [ABSTRACT FROM AUTHOR]

The study of long-distance migration provides insights into the habits and performance of organisms at the limit of their physical abilities. The Arctic tern Sterna paradisaea is the epitome of such behavior; despite its small size (<125 9), banding recoveries and at-sea surveys suggest that its annual migration from boreal and high Arctic breeding grounds to the Southern Ocean may be the longest seasonal movement of any animal. Our tracking of 11 Arctic terns fitted with miniature (1.4-g) geolocators revealed that these birds do indeed travel huge distances (more than 80,000 km annually for some individuals). As well as confirming the location of the main wintering region, we also identified a previously unknown oceanic stopover area in the North Atlantic used by birds from at least two breeding populations (from Greenland and Iceland). Although birds from the same colony took one of two alternative southbound `migration routes following the African or South American coast, all returned on a broadly similar, sigmoidal trajectory, crossing from east to west in the Atlantic in the region of the equatorial Intertropical Convergence Zone. Arctic terns clearly target regions of high marine productivity both as stopover and wintering areas, and exploit prevailing global wind systems to reduce flight costs on long-distance commutes. [ABSTRACT FROM AUTHOR]

We found that synchronous fluctuations of two congeneric seabird species across the entire Arctic and sub-Arctic regions were associated with changes in sea surface temperatures (SST) that were linked to two climate shifts, in 1977 and again in 1989. As the SST changes linked to climate shifts were congruent at the scale of ocean basins, fluctuations of these species occurred similarly at continental or basin scale. Changes in colony sizes were examined for a decade following climate shifts. The magnitude of the SST shift was more important than its direction in determining the subsequent rate of population change. Seabirds declined when the SST shift was large and increased when the shift was small, although the effect differed between the Arctic-breeding species and the more temperate-breeding congener. The Arctic species, Thick-billed Murre ( Uria lomvia) increased most rapidly when SST warmed slightly, while the temperate species, Common Murre ( Uria aalge) showed most rapid increase with moderate cooling. Both showed negative trends with large temperature shifts in either direction. This pattern was replicated during both climate oscillations. Negative population trends in seabirds presumably indicate the alteration of underlying food webs. Hence, similar widespread fluctuations in response to climate shifts are likely for other ecosystem components (marine mammals, fish, and invertebrates). [ABSTRACT FROM AUTHOR]

1. Buffer effects occur when increases in population size result in an increasing proportion of a population inhabiting poor quality sites. When there are fitness costs to inhabiting poor sites, buffer effects can potentially regulate population sizes. In migratory populations, the regulatory capacity of buffer effects will clearly be influenced by their role in both the breeding and nonbreeding seasons, but previous studies have been restricted to one season only. 2. Icelandic black-tailed godwits Limosa limosa islandica are currently increasing in number and previous studies have revealed a large-scale buffer effect operating on the wintering grounds. 3. Here, we reconstruct the pattern of population expansion and colonization of new breeding grounds, in relation to breeding habitat quality, to investigate whether a buffer effect is also operating during the breeding season. 4. Godwit breeding success is higher in marsh habitats than in dwarf-birch bogs. Prey densities are also higher in marsh habitats, and breeding success increases with the density of shallow pools, which are more common on marsh sites. Large lowland basins with higher marsh coverage were colonized earlier than small ones with low marsh coverage. Recent colonizations have been into basins that are closer to occupied sites and have higher cover of dwarf-birch bog. 5. Thus godwits appear to be expanding into poorer quality breeding habitat as well as poorer quality winter habitat. The large spatial scale of these analyses and the fitness costs of occupying poor quality sites suggest that this double buffer effect is likely to play a key role in regulating this expanding population. In most migratory populations, some level of density dependence is likely to operate at both ends of the range. Double buffer effects may therefore be a common phenomenon and an important mechanism regulating migratory populations. [ABSTRACT FROM AUTHOR]

Focuses on a study about the adult survival of Black Guillemot or Cepphus grylle based on the capture-recapture data set collected in 1974-1995 in a colony in western Iceland. No evidence of variation over time on adult survival; Difficulty in capturing birds due to nests in shorebird or tern territories; Comparison with other Atlantic alcids; Apparent first-year survival; Effects of variation in capture effort; Alcid life histories.

The article cites a study that analyses a dataset on historical capture-mark-recapture of female common Scoters, caught on nests at a farm in Mývatn, Iceland. The data was collected during a program from June 1925 to August 1958, by which incubating females were captured and ringed with aluminum leg rings.