Jón Einar Jónsson

University of Iceland | HI · Research Centre at Snæfellsnes

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 comm...

Capsule Common Eiders at Rif in west Iceland commonly show joint nest attendance, which may be an exaggerated behavioural response to the visual stimulus of many nests so close to their own nest. This represents a new insight into incubation behaviour in colonies with extremely high nest densities.

Climate change studies have detected earlier spring arrival of breeding birds. However, first nest dates (date first nests were found), which commonly provide the metric for earlier arrival, can be biased by population size or sampling effort. Our aims were to determine if: 1) first nest dates and median nest date (date when at least 50 % of all fe...

Bird species on islands are strongly impacted by biological invasions, with the Icelandic common eider (Somateria mollissima borealis) being particularly threatened. Down collection by local families in Breiðafjörður, West Iceland, provided long‐term datasets of nests from two archipelagos, covering 95 islands over 123 years and 39 islands over 27...

Global climate change is causing abiotic shifts such as higher air and ocean temperatures and disappearing sea ice in Arctic ecosystems. These changes influence Arctic-breeding seabird foraging ecology by altering prey availability and selection, affecting individual body condition, reproductive success, and exposure to contaminants such as mercury...

Background The geographic expansion and evolution of A/Goose/Guangdong/1/1996(H5N1) (Gs/GD) lineage H5Nx highly pathogenic avian influenza (HPAI) viruses since 1996 have raised awareness of enzootic circulation among migratory birds and the potential for intercontinental transport and spread. Recent Pacific- and Atlantic-route introductions of HPAI...

Background: The geographic expansion and evolution of A/Goose/Guangdong/1/1996(H5N1) (Gs/GD) lineage H5Nx highly pathogenic avian influenza (HPAI) viruses since 1996 have raised awareness of enzootic circulation among migratory birds and the potential for intercontinental transport and spread. Recent Pacific- and Atlantic-route introductions of HPA...

Developing standardized methodology to allow efficient and cost-effective ecological data collection, particularly at scale, is of critical importance for understanding species' declines. Remote camera networks can enable monitoring across large spatiotemporal scales and at relatively low researcher cost, but manually analysing images and extractin...

The evolution of bird colouration has become a central topic in behavioural and evolutionary ecology, and assessing the accurate colour is imperative. Female common eiders generally are greyish brown in colour with dark barring on the body but show individual variation from light grey to dark brown. The eiders in the Faroe Islands (Somateria mollis...

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are h...

Influenza A viruses (IAV) circulate endemically among many wild aquatic bird populations that seasonally migrate between wintering grounds in southern latitudes to breeding ranges along the perimeter of the circumpolar arctic. Arctic and subarctic zones are hypothesized to serve as ecologic drivers of the intercontinental movement and reassortment...

Since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of mercury (Hg) on Arctic biota in 2011 and 2018, there has been a considerable number of new Arctic bird studies. This review article provides contemporary Hg exposure and potential health risk for 36 Arctic seabird and shorebird species, represent...

Influenza A viruses (IAV) circulate endemically among many wild aquatic bird populations that seasonally migrate between wintering grounds in southern latitudes to breeding ranges along the perimeter of the circumpolar arctic. Arctic and subarctic zones are hypothesized to serve as ecologic drivers of the intercon-tinental movement and reassortment...

Supplementary data to "Six pelagic seabird species of the North Atlantic engage in a fly-and-forage strategy during their migratory movements"

Brood counts of eiders in Breiðafjörður 2007-2021

Tracking data of marine predators are increasingly used in marine spatial management. We developed a spatial data set with estimates of the monthly distribution of 6 pelagic seabird species breeding in the Northeast Atlantic. The data set was based on year-round global location sensor (GLS) tracking data of 2356 adult seabirds from 2006-2019 from a...

Bird migration is commonly defined as a seasonal movement between breeding and non-breeding grounds. It generally involves relatively straight and directed large-scale movements, with a latitudinal change, and specific daily activity patterns comprising less or no foraging and more traveling time. Our main objective was to describe how this general...

Migratory seabirds are exposed to various pollutants throughout their annual cycle. Among them, mercury (Hg) is of particular concern given large impacts on animals’ health. Recent studies suggest that winter is a critical period for seabirds when contamination by Hg can be higher than other times of year. However, individuals within and between sp...

Synchronous reproduction of birds has often been explained by benefits from nesting together, but this concept fails to explain observed intraspecific variation and climate-mediated changes of breeding synchrony. Here, we present a theoretical model of birds that store resources for reproduction (capital breeders) to show how breeding synchrony, cl...

Human industrialization has resulted in rapid climate change, leading to wide-scale environmental shifts. These shifts can modify food web dynamics by altering the abundance and distribution of primary producers (ice algae and phytoplankton), as well as animals at higher trophic levels. Methylmercury (MeHg) is a neuro-endocrine disrupting compound...

The first avian cholera outbreaks in wild birds in Iceland occurred at the eider colony Hraun, North Iceland, in the springs 2018 and 2019. Avian cholera is caused by the bacteria Pasteurella multocida and is one of the most fatal diseases in wild birds. Outbreaks can kill large numbers of birds within days, often without any visible signs of illne...

Seabird-fishery interactions are a known and common phenomenon of conservation concern. Here, we highlight how light-level geolocators provide promising opportunities to study these interactions. By examining raw light data, it is possible to detect encounters with artificial lights at night, while conductivity data give insight on seabird behaviou...

A wide range of species, including marine mammals, seabirds, birds of prey, fish and bivalves, were investigated for potential population health risks resulting from contemporary (post 2000) mercury (Hg) exposure, using novel risk thresholds based on literature and de novo contamination data. The main geographic focus is on the Baltic Sea, while da...

The common eider, Somateria mollissima, is a large Holarctic sea duck, composed of six recognized subspecies. The subspecies statuses are formed on the basis of morphological data. The common eiders in the Faroe Islands and Iceland have been assigned to the subspecies S. m. faeroeensis and S. m. borealis, respectively. Previously, Tiedemann et al....

1. We studied a metapopulation of great cormorant (Phalacrocorax carbo) in Iceland, using complete aerial censuses of nests in 25 years during 1975-2015. Age composition was estimated in 1998-2014 by ground surveys in September and February. Brood size was estimated from aerial photographs in 2007-2015. 2. Weather, food, breeding habitat and densit...

In 2014, 22 islands in Breiðafjörður, West-Iceland were mapped for vegetation. The purpose to this study was to map vegetation types, distribution of plant species and overgrowing status in islands which differs in size, topography, bedrock composition, land use and birdlife activity. Most of the islands in this study have not been mapped before. T...

Plasticity in organ and muscle size and function allows individuals to respond to changes in food quality or foraging behaviour, in accordance with cost-benefit hypotheses. Lesser Snow Geese Anser caerulescens caerulescens (hereafter Snow Geese) winter in rice-prairie and coastal-marsh habitats in southwest Louisiana, where the time that the birds...

Availability of benthic invertebrates is the main limiting agent of female eider body condition prior to breeding. However, the availability of capelin roe may play an important role in building up adipose tissue. Eider nest counts in four regions were correlated with the capelin fisheries and the capelin fishing effort advisory issued by the Icela...

Insulation is an essential component of nest structure that helps provide incubation requirements for birds. Many species of waterfowl breed in high latitudes where rapid heat loss can necessitate a high energetic input from parents and use down feathers to line their nests. Common Eider (Somateria mollissima) nest down has exceptional insulating p...

This report sums up the result from a three-year lasting study regarding the unique eider down. Eider down from 19 colonies was collected and we measured various parameters such as fill power, cohesion and resilience. Overall, this is the largest and most in-depth study of eider down ever performed.

Physical exertion during growth can affect ultimate size and density of skeletal structures. Such changes from different exercise regimes may explain morphological differences between groups, such as those exhibited by lesser snow geese (Chen caerulescens caerulescens; hereafter snow geese) foraging in southwest Louisiana. In rice-prairie habitats...

Capsule: The occurrence of high numbers of ectoparasites in nests of Common Eiders may be related to nest densities and nesting behaviour.Aims: To estimate abundances of ectoparasites and occurrence of blood-covered eggs, and relate those to nest bowl ages, nest bottom material and the incubation stages of eggs, in nests at two different Common Eid...

Annual nest counts were collated from eider farmers to study trends in nest numbers in 40 eider colonies in Iceland. The longest nest count series spanned 101 years but the shortest were 6 years. Trends were grouped by time series length and regions of the country. Data were available from two colonies for the first three decades of the 20th Centur...

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 sampl...

Here, our objective was to determine whether the annual proportion of Snow Geese using coastal marsh habitats in southwest Louisiana varied annually, as compared to rice-prairie habitats, possibly in relation to hunting pressure or rice production. We predicted that: 1) increased rice production would make rice-prairies more attractive for Snow Gee...

Several avian species have shifted their wintering or staging areas north in response to advancing onset of spring. Our objectives were to determine whether (1) the latitudinal distribution of recoveries changed for Chen caerulescens caerulescens (Lesser Snow Goose; hereafter Snow Goose) banded in southwest Louisiana, and (2) annual proportions of...

We review the current and future threats to duck populations that breed, stage, moult and/or winter in the Nordic countries. Migratory duck species are sensitive indicators of their changing environment, and their societal value confirms the need to translate signals from changes in their distribution, status and abundance into a better understandi...

Capsule Large-scale variation in breeding output of Greylag geese Anser anser is negligible across Iceland but detectable variation is likely related to spring temperature. Aims To identify large-scale spatial and annual variation in breeding parameters to support sustainable utilization and conservation of Greylag geese that are a quarry species i...

Lesser Snow Geese Chen caerulescens caerulescens (hereafter Snow Geese) use two wintering habitats in southwest Louisiana. Snow Geese in coastal marshes generally have larger bodies and proportionally thicker bills, longer skulls and longer culmen lengths than do those in adjacent rice-prairies. An important question is whether or not these morphs...

Summary Capsule Great Skuas Stercorarius skua wintering in different areas might be exposed to different feeding conditions and therefore spend different amount of time in flight (foraging or searching for food). Aims To compare percent of time daily spent in flight (foraging or searching for food) between different winter areas. Methods In 2008,...

Avian influenza virus (AIV) in wild birds has been of increasing interest over the last decade due to the emergence of AIVs that cause significant disease and mortality in both poultry and humans. While research clearly demonstrates that AIVs can move across the Pacific or Atlantic Ocean, there has been no data to support the mechanism of how this...

(map) Numbers indicate locations of 17 colonies in Iceland which provided breeding numbers of common eider (Somateria mollissima) used in this study; numbers refer to numbers of colonies in Table 1. Names are the weather stations considered in this study. (TIF)

Principal components analysis of weather data from Stykkishólmur, West Iceland, for different periods where eider nests were counted in Iceland. The first two principal scores (PC) were used as indices of local weather. The highest loading for each variable in each analysis is indicated in bold. (DOC)

The breeding population of Great Cormorants (Phalacrocorax carbo carbo) in Iceland has been censused since 1975. Over the first series of years thereafter, numbers appeared to be stable (approximately 3,000 nests counted at irregular intervals). After 1990 there were indications of a decline. Annual monitoring began in 1994. From then on, the total...

Breiðafjörður is an important molting, breed-ing, and wintering area for about 25 % of the Icelandic common eider (Somateria mollissima) population. How-ever, feeding habits of eiders in this area have not been investigated until now. Prey selection was analyzed from 192 stomach samples (esophagus and proventriculus) collected in spring 2007–2010....

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, afte...

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, afte...

Birds change nest sites between years in response to breeding success in previous years, activities of other breeders, or weather conditions. Sixteen years of banding data and nest counts of the Common Eider in Rif, western Iceland, were used to evaluate probability of switching nest islands. The two man-made islands studied had different substrate...

Incubating common eiders (Somateria mollissima) insulate their nests with down to maintain desirable heat and humidity for their eggs. Eiderdown has been collected by Icelandic farmers for centuries, and down is replaced by hay during collection. This study determined whether down collecting affected the female eiders or their hatching success. We...

Common Shelduck Tadorna tadorna were surveyed at the mudflat of Andakílsós, W-Iceland, in summers 2007 and 2008. The autumn population consists of nearly five hundred birds, were approximately 45% of which are young from the summer. It likely that 30-60 pairs are responsible for the breeding output in this area. In addition to breeding adults, 100-...

Sex ratios often are uneven in birds, especially northern hemisphere ducks. During winter, the male:female ratio is closest to 1:1 in southern parts of the range, whereas it tends to become progressively more skewed towards males with increasing latitudes. This has been explained by two hypotheses: (1) males prefer to winter near the breeding groun...

Blackwater National Wildlife Refuge on the Delmarva Peninsula, Maryland, USA has been the wintering area of a small population of Lesser Snow Geese (Chef caerulescens caerulescens; LSGO) since the 1930s. Snow Geese primarily pair in wintering areas and gene flow could be restricted between this and other LSGO wintering populations. Winter pair form...

Smaller species are less likely to maintain families (or other forms of social groups) than larger species and are more likely to be displaced in competition with larger species. We observed mixed-species flocks of geese in southwest Louisiana and compared frequencies of social groups and success in social encounters of Lesser Snow Geese (Chen caer...

Changes in bird populations and their phenology (i.e. timing of nesting and migration) are increasingly linked to global climatic changes, particularly at temperate and Arctic latitudes. These patterns arise from local- and regional-scale effects of weather on demography but long-term time-series data necessary to explore these relationships are ra...

Body size affects foraging and forage intake rates directly via energetic processes and indirectly through interactions with social status and social behaviour. Ambient temperature has a relatively greater effect on the energetics of smaller species, which also generally are more vulnerable to predator attacks than are larger species. We examined v...

Seabird populations are much discussed because of possible impacts of global climate change. Eider ducks (Somatereae) are a monophyletic group comprised of four species of specialized ducks that all live along the Arctic coastline. Most populations are listed as of special concern with a few exceptions, notably the Common Eider (Somateria mollissim...

Snow Goose Chen caerulescens is a N-American species that is sighted in Iceland on a yearly basis. A Snow Goose first wintered in Iceland in 2002-2003 and in the summer of 2007 this first breeding attempt was recorded. The author visited the nest 19 June 2007 and measured both the birds and the eggs. The birds were identified as Greater Snow Geese...

Smaller species are less likely to maintain families (or other forms of social groups) than larger species and are more likely to be displaced in competition with larger species. We observed mixed-species flocks of geese in southwest Louisiana and compared frequencies of social groups and success in social encounters of Lesser Snow Geese (Chen caer...

The body-size hypothesis predicts that nest attendance is positively related to body size among waterfowl and that recess duration is inversely related to body size. Several physiological and behavioral characteristics of Ross’s geese (Chen rossii) suggest that females of this species should maintain high nest attendance despite their relatively sm...

Many bird species use human-made habitats and an important issue is whether these are equally suitable foraging habitats as are historical, natural habitats. Historically, Lesser Snow Geese (Chen caerulescens caerulescens; hereafter Snow Geese) wintered in coastal marshes in Louisiana but began using rice-prairies within the last 60 years. Time spe...

Most birds develop brood patches before incubation; epidermis and dermis in the brood patch region thicken, and the dermal connective tissue becomes increasingly vascularized and infiltrated by leukocytes. However, current dogma states that waterfowl incubate without modifications of skin within the brood patch region. The incubation periods of les...

AAAAAAAA.—We investigated eff ects of ecological and physiological factors on brood patch area and prolactin levels in free-ranging Lesser Snow Geese (Chen caerulescens caerulescens; hereaa er "Snow Geese") and Ross's Geese (C. rossii). On the basis of the body-size hypothesis, we predicted that the relationships between prolactin levels, brood pat...

We investigated effects of ecological and physiological factors on brood patch area and prolactin levels in free-ranging Lesser Snow Geese (Chen caerulescens caerulescens; hereafter “Snow Geese”) and Ross's Geese (C. rossii). On the basis of the body-size hypothesis, we predicted that the relationships between prolactin levels, brood patch area, an...