Long-tailed Ducks Clangula Hyemalis Research Articles

Exploratory Surveys of Migratory Birds Breeding in the Western and Central Canadian Arctic 2005–2011

Abstract The Canadian Arctic and subarctic are the primary breeding areas of many species of North American water and land birds. Because of the remote location and the logistical difficulties of working there, wildlife biologists have not systematically surveyed most important areas for wildlife, nor have they surveyed these areas very frequently. During the summers of 2005–2011, various Joint Ventures, and U.S., Canadian, and state wildlife agencies and other partners funded exploratory fixed-wing aircraft surveys of migratory birds (excluding passerines and shorebirds) in important habitats in Canada's western and central Arctic. Our objectives were to provide access to the complete survey dataset (all bird and mammal observations and associated location data) and summarize information on several species. Thus, we produced maps of average relative density and estimates of abundance in the survey area for cackling geese Branta hutchinsii, greater white-fronted geese Anser albifrons, tundra swans Cygnus columbianus, king eiders Somateria spectabilis, long-tailed ducks Clangula hyemalis, white-winged Melanitta fusca and surf Melanitta perspicillatas scoters, and yellow-billed Gavia adamsii, red-throated Gavia stellata, and Pacific Gavia pacifica loons. We reviewed previous survey efforts in the area and, where possible, compared them with our results.

Long Nights, Airplanes, and Avian Surgery: A Tale of Working With Volunteers to Study Long-tailed Ducks (Clangula hyemalis) Wintering on Lake Michigan

Evidence suggests that wintering populations of long-tailed ducks along the Atlantic and Pacific coasts are in decline, but little is known about wintering populations on Lake Michigan. Researchers seek answers to basic questions regarding habitat use and migration patterns (temporal and spatial) of long-tailed ducks that winter on Lake Michigan, by using surgically implanted satellite transmitters. The processes of locating the birds, capturing and implanting satellite transmitters, and interpreting the results were challenging, and efforts relied on dedicated researchers, veterinarians, resource managers, and many volunteers.

Interspecific patterns of trace elements in sea ducks: Can surrogate species be used in contaminants monitoring?

As industrial development, aerial deposition of pollutants, and chemical releases from thawing permafrost increase in the Arctic, there is need to monitor exposure to contaminants in a range of species. Surrogate or bioindicator species are often used to represent groups of taxa and are typically selected for their wide geographic ranges and ease of sampling. However, it is seldom known how well surrogates exemplify different species, ages, or breeding stages in different areas. We examined multiple trace elements in incubating females of five sea duck species (long-tailed ducks Clangula hyemalis, Steller’s eiders Polysticta stelleri, spectacled eiders Somateria fischeri, king eiders S. spectabilis, and common eiders S. mollissima), in pre-laying spectacled eiders, and in brood-rearing female spectacled and king eiders and their ducklings, among four areas on the Arctic Coastal Plain of Alaska, USA. For Se, Cd, and Cu that are probably acquired during the nonbreeding period, Se and Cd in the blood of hens varied appreciably among species, whereas all species appeared to regulate Cu at similar concentrations. Levels of blood Hg and Pb sampled during incubation were inconsistent among species, apparently reflecting variable exposure on breeding areas. During incubation, species of similar body mass had similar patterns of elements. Se, Cu, and Pb differed substantially across the breeding season in spectacled eiders, as well as between ducklings and hens of spectacled and king eiders. Although analysis of feathers avoids invasive sampling, patterns of element concentrations in feathers differed from those in blood. Species of comparable body mass and life history traits sampled at a given site generally had similar concentrations of trace elements in blood, suggesting some utility as surrogates, but still showed regional variation. Our results suggest that for sea ducks, surrogate species of varying body mass and life history traits may not consistently reflect levels of exposure across taxa, or even among congeners or sex-age classes in the same areas. Biomonitoring for contaminants should use species of comparable mass as indicators at small spatial scales, but at the regional scale, should focus on specific taxa of concern.

Results of the January 2017 waterbird census in Slovenia

Summary In 2017, the International Waterbird Census (IWC) was carried out in Slovenia on January 14 and 15. Waterbirds were counted on all larger rivers, along the entire Slovenian Coastland and on most of the major standing waters in the country. During the census, in which 235 observers took part, 413 sections of the rivers and coastal sea with a total length of 1,427 km and 200 other localities (164 standing waters and 36 streams) were surveyed. The census was characterized by harsh winter conditions and high proportion of frozen water bodies. Altogether, 51,790 waterbirds of 61 species were counted. Thus, the number of waterbirds and the number of species recorded were close to the 21-year average. The highest numbers of waterbirds were counted in the Drava count area, i.e. 20,064 individuals (38.7% of all waterbirds in Slovenia). By far the most numerous species was Mallard Anas platyrhynchos (46.1% of all waterbirds), followed by Coot Fulica atra (6.8% of all waterbirds), Cormorant Phalacrocorax carbo (5.9% of all waterbirds), Black-headed Gull Chroicocephalus ridibundus (5.7% of all waterbirds) and Mute Swan Cygnus olor (3.9% of all waterbirds). The number of 1,000 counted individuals was also surpassed by Yellow-legged Gull Larus michahellis, Teal An. crecca, Tufted Duck Aythya fuligula, White-fronted Goose Anser albifrons, Pygmy Cormorant P. pygmeus and Grey Heron Ardea cinerea. Among the rarer recorded species, the Red-breasted Goose Branta ruficollis (registered for the first time during the January Waterbird Censuses and only for the third time ever in Slovenia) and Barnacle Goose Branta leucopsis (the first probable A category individual for IWC and Slovenia) deserve special mention. Numbers of the following species were the highest so far recorded during the IWC: Mandarin Duck Aix galericulata (together with 2006 and 2012), Pintail An. acuta, Ferruginous Duck Ay. nyroca, Long-tailed Duck Clangula hyemalis (together with 2003), Goosander Mergus merganser, Pygmy Cormorant, Herring Gull L. argentatus and Caspian Gull L. cachinnans. Number of Pochards Ay. ferina was the lowest so far recorded during the IWC.

<b>A rare sighting of the Long-tailed Duck <I>Clangula hyemalis</I> (Linnaeus, 1758) (Aves: Anseriformes: Anatidae) over a four-week period in northwestern India: first detailed scientific documentation in 73 years</b>

The Long-tailed Duck Clangula hyemalis is a circumpolar species, breeding in North America, Europe and Asia, however, it is currently among the rarest ducks in Asia, and assessed as globally Vulnerable. Conservation actions explicitly include improved monitoring efforts in Asia. We report the second sighting of this species at the Gharana Wetland Reserve the third in northwestern India, in over 73 years, and have carefully documented our findings over four weeks.

Hanöbukten, an important wintering area for waterbirds in South Sweden

Hanöbukten in SE Sweden (including Blekinge archipelago) is an important wintering and staging area for a number of waterbird species. The inshore parts have been covered by counts from the shore during the International Waterbird Counts (IWC) since 1969. In the present study we analyze these counts for the period 1969–2014. When the counts started the total number of wintering waterbirds varied between 20,000 and 40,000 per year. However, from the early 1990s the number doubled, reaching 60,000 to 80,000 birds per year. All species with the exception of the Long-tailed Duck Clangula hyemalis showed similar increase. The area had a high proportion of the Swedish wintering population of Pochard Aythya ferina and Smew Mergellus albellus. Large numbers of Tufted Duck Aythya fuligula also wintered in the area, and some parts of the archipelago had internationally important concentrations of Tufted Duck and Smew. The increase in numbers in the study area showed the same pattern as in all Sweden and was most probably a result of milder winters in recent years.

Trematode fauna (Platyhelminthes: Digenea) of some sea ducks wintering on the southern Baltic coast (NW Poland) – a general comparison

ABSTRACTThe common scoter Melanitta nigra, velvet scoter M. fusca and long-tailed duck Clangula hyemalis (Aves: Anatidae) are among the more abundant sea ducks on the southern coast of the Baltic in winter, but their parasitic trematode fauna (Platyhelminthes, Digenea) in this region is little known. The aim of this study, conducted in 2007–2009, was a general comparison of the trematode fauna of these ducks in NW Poland. The prevalence and intensity of trematode infection were 68.3% and 119.9 in common scoter (101 examined), 77.6% and 13.1 in velvet scoter (58 examined) and 70.6% and 23.7 in long-tailed duck (68 examined). The following trematodes were found: Diplostomum pungitii, Apatemon gracilis, Australapatemon minor, Typhlocoelum sisowi, Echinochasmus spinulosus, Echinoparyphium recurvatum, Psilostomum brevicolle, Psilotrema simillimum, Catatropis verrucosa, Notocotylus attenuatus, N. gibbus, Paramonostomum alveatum, Prosthogonimus ovatus, Levinseniella propinqua, Gymnophallus bursicola and Cryptocotyle concava. The common scoter differs from the velvet scoter and long-tailed duck in its statistically significantly higher prevalence of G. bursicola; from long-tailed duck in its higher prevalence and greater intensity of infection with P. alveatum; and from velvet scoter in its greater intensity of infection with C. concava. The velvet scoter is distinguished from the long-tailed duck by its greater intensity of infection with P. brevicolle, lower prevalence of L. propinqua and lower intensity of infection with C. concava. Links between the differences found and the biology and ecology of the hosts, as well as the means of transmission of the parasites, are also discussed.

Changes in numbers and distribution of wintering Long-tailed Ducks Clangula hyemalis in Swedish waters during the last fifty years

The Long-tailed Duck Clangula hyemalis is the most common wintering waterfowl in Swedish marine waters but it is not well covered in the International Midwinter Counts due to its offshore distribution making special surveys necessary for the species. Surveys covering the entire Baltic Sea were organized for the first time in 1992/1993 with follow-up surveys in 2007–2011 and 2016. In Sweden, aerial line transect surveys covered all areas of importance for the Long-tailed Duck during the last two all-Baltic surveys. In the 1970s extensive regional surveys were done from coastguard boats and airplane. The total wintering population of Long-tailed Duck was estimated to be around 370,000 individuals in 2016 compared to 436,000 in 2009, and in the order of 1,400,000 in 1992/1993, indicating an ongoing decrease. Comparing the more recent surveys with the surveys from the 1970s, the most marked changes in wintering numbers were found east of Gotland, where only a small proportion of the numbers estimated in the 1970s remained. Decreases were also found in the waters around Öland, whereas no marked changes were noted for the smaller wintering populations of the east coast archipelagos.

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

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.

The importance of offshore areas in southern Öresund, Sweden, for staging and wintering sea ducks

The occurrence of wintering and spring-staging sea ducks in the southern part of Swedish Öresund was surveyed from air and ship during the period 2001–2011. Altogether 22 air and 20 boat surveys were made during the months November–May and here we present the results regarding five commonly recorded sea ducks. We present the numbers recorded and the general time pattern of occurrence during winter and spring in the area. Recorded numbers are then used for evaluating the importance of the area, both in relation to national wintering totals as well as to international (Baltic) totals. Southern Swedish Öresund is of no larger importance for Long-tailed Duck Clangula hyemalis in winter and spring. The area is however of national importance for both Velvet Scoter Melanitta fusca and Common Scoter Melanitta nigra in winter. Peak numbers of Common Scoters do also reach international importance. Southern Swedish Öresund is of large national and international importance for both wintering and spring-staging Eider Somateria mollissima and Red-breasted Merganser Mergus merganser.

Spring staging of Eiders Somateria mollissima in some Swedish east coast archipelagos and at Gotland 2009 and 2010

The Eider Somateria mollissima is a commonbreeding species in the Baltic. In 2008, Ottossonet al. (2012) estimated that the breeding populationof Eiders in the archipelagoes of the four Swedishcounties of Kalmar, Ostergotland, Sodermanlandand Stockholm was in the order of 103 000 pairs,whereas the breeding population around Gotlandwas about 6000 pairs. The distribution of breedingEiders in several regions is well known fromextensive surveys (cf. Gezelius 2012, Sveriges OrnitologiskaForening 2009). On the other hand, thedistribution of staging Eiders in early spring hasnot been studied on a regional level before.During 2009‒2011, extensive offshore surveyswere undertaken in the Baltic (Nilsson 2012, Skovet al. 2011). The main target species was the LongtailedDuck Clangula hyemalis. For various reasonssome areas (the east coast archipelagos fromGavle–Krakelund in 2009 and eastern Gotland in2010) were surveyed during the time for the springmigration of the Eider (which is still winter for theLong-tailed Ducks, leaving the Baltic in May). Inthis short contribution I present the results fromthese surveys for the Eider to give first snapshotsof the distribution of the species along the Balticcoast of Sweden during the migration period.

Decline of Long-tailed Duck Clangula hyemalis numbers in the Pomeranian Bay revealed by two different survey methods

Abundance of Long-tailed Ducks Clangula hyemalis wintering in the Pomeranian Bay was monitored between 1988 and 2014, using both ship-based and aerial surveys and cor-recting for distance dependent detection. Aerial surveys were conducted using an im-proved transect division and a double observer design to estimate detection probability near the transect line. As the latter probability was considerably below 1, we applied an additional correction factor for observer efficiency. After correcting for observer effi-ciency in aerial surveys, the two methodological approaches yielded similar densities, though an apparent underestimation in aerial surveys warrants further cross-validation. Density estimates from both platforms were merged for further analysis. After reaching peak levels in 1992 and 1993, Long-tailed Duck winter densities in the Pomeranian Bay declined by 82% until 2010. This decline was part of an overall decline in numbers throughout the Baltic Sea. An apparent increase since 2010, which was likely due to local ice-induced movements, indicates that habitats in the study area may still support high densities today.

A lift-net method for capturing diving and sea ducks

Alternatives to bait-trapping waterfowl are often necessary when studying health or body condition, when targeting species that are not easily attracted to bait or those that occur in deep-water habitats where bait-trapping can be difficult. We designed an active netting method for capturing diving and sea ducks, which we deployed at 8 sites in Lake Ontario, Canada from 2006 to 2007 and 2011 to 2012. A mist net suspended horizontally 0.5 m below the water surface was lifted out of the water when ducks swam over the capture area. The technique requires a stationary structure to anchor one end and is lifted out of the water by hand or using a vehicle on the non-anchored end using attached ropes. We used structures including docks and walls of a shipping channel to secure ropes, but other structures could be used. Catch rates were 0.63 birds/hr for greater scaup (Aythya marila), and 0.65 birds/hr for long-tailed ducks (Clangula hyemalis). In comparison, catch rates for floating mist nets were 0.08 birds/hr and 0.86 birds/hr for greater scaup and long-tailed ducks, respectively. Equipment costs to build a lift-net were 85% less than to build a floating mist net. © 2013 The Wildlife Society.

Wintering Sea Duck Distribution Along the Atlantic Coast of the United States

AbstractAlthough monitoring data for sea ducks (Tribe Mergini) are limited, current evidence suggests that four of the most common species wintering along the eastern coast of the United States—long-tailed duck Clangula hyemalis, white-winged scoter Melanitta fusca, surf scoter Melanitta perspicillata, and black scoter Melanitta americana—may be declining, while the status of American common eider Somateria mollissima dresseri is uncertain. The apparent negative trends, combined with the fact that sea duck life histories are among the most poorly documented of North American waterfowl, have led to concerns for these species and questions about the impacts of human activities, such as hunting, as well as catastrophic events and environmental change. During winter, thousands of sea ducks are found along the U.S. Atlantic coast, where they may be affected by proposed wind-power development, changes to marine traffic, aquaculture practices, sand mining, and other coastal development. Possible impacts are difficult to quantify because traditional winter waterfowl surveys do not cover many of the marine habitats used by sea ducks. Thus, the U.S. Fish and Wildlife Service conducted an experimental survey of sea ducks from 2008 to 2011 to characterize their winter distributions along the U.S. Atlantic coast. Each year, data were collected on 11 species of sea ducks on >200 transects, stretching from Maine to Florida. In this paper, we describe distribution of common eider, long-tailed duck, white-winged scoter, surf scoter, and black scoter. Densities of the two species with the most northerly distribution, white-winged scoter and common eider, were highest near Cape Cod and Nantucket. Long-tailed duck was most abundant around Cape Cod, Nantucket Shoals, and in Chesapeake Bay. Surf scoter also concentrated within Chesapeake Bay; however, they were additionally found in high densities in Delaware Bay, and along the Maryland–Delaware outer coast. Black scoter, the most widely distributed species, occurred at high densities along the South Carolina coast and the mouth of Chesapeake Bay. Spatial patterns of high-density transects were consistent among years for all species except black scoter, which exhibited the most interannual variation in distribution. The distance from land, depth, and bottom slope where flocks were observed varied among species and regions, with a median distance of 3.8 km from land along the coastal transects and 75% of flocks observed over depths of <16 m. Common eider and long-tailed duck were observed closer to shore and over steeper ocean bottoms than were the three scoter species. Our results represent the first large-scale quantitative description of winter sea duck distribution along the U.S. Atlantic coast, and should guide the development of sea duck monitoring programs and aid the assessment of potential impacts of ongoing and proposed offshore development.

Factors Affecting Lipid Reserves and Foraging Activity of Buffleheads, Common Goldeneyes, and Long-tailed Ducks during Winter at Lake Ontario

Abstract. To identify factors potentially limiting the abundance of ducks at the northern latitude of Lake Ontario, we investigated whether the lipid levels and foraging behavior of sea ducks wintering there were best explained by endogenous or exogenous mechanisms. We used an information-theoretic approach to evaluate if date (14 December–15 March; endogenous mechanism), percentage ice cover of Lake Ontario (long-term exogenous mechanism), short-term ambient temperature (exogenous mechanism), or some combination of these factors best explained variation in lipid reserves and foraging effort of the Bufflehead (Bucephala albeola), Common Goldeneye (B. clangula), and Long-tailed Duck (Clangula hyemalis). In the Long-tailed Duck, date explained lipid declines best, whereas in the Bufflehead and Common Goldeneye lipid reserves varied negatively with percentage ice cover. Conditions at our study site appeared to necessitate foraging because all species foraged, on average, ≥69% of daylight hours, and they incr...

Distribution and numbers of wintering sea ducks in Swedish offshore waters

The first survey of seaducks covering the offshore waters of the entire Baltic was undertaken in 1992/1993, when, however, the Swedish waters were covered with relatively few ship surveys. The second all Baltic survey 2007–2011 included extensive aerial surveys of all Swedish offshore waters. This paper presents the Swedish data from these two surveys, supplemented with data from several other but partial surveys back to the early 1970s. The most numerous wintering seaduck in the Swedish waters was the Long-tailed Duck Clangula hyemalis with an estimated population of 1.41 million in 1992/1993, decreasing with 69% to 0.44 million in 2007–2009. Hoburg bank south of Gotland and the two Midsjö banks accounted for the vast majority of these ducks. In 2009–2011 only small numbers of scoters Melanitta fusca and M. nigra were found in Swedish Baltic waters. The totals for the Eider Somateria molissima and Red-breasted Merganser Mergus serrator were estimated at 20,000 and 8,000, respectively. Larger numbers of Eiders (50,000) and scoters (20,000) were found on the west coast.

Trophic peculiarities of the Great Cormorant, Grey Heron and Long-tailed Duck on the Baltic Sea Lithuanian coast: a stable isotope approach

The stable isotopes of nitrogen (δ15N) and carbon (δ13C) were analysed in the feathers of the Great Cormorant (Phalacrocorax carbo), Grey Heron (Ardea cinerea) and Long-tailed Duck (Clangula hyemalis) staying in the different seasons at the Lithuanian Baltic Sea coast. Stable isotope ratios in bird feathers represented dietary variations and foraging habitats during the feather growth period. Adult Great Cormorants fed juveniles by smaller fish at the beginning of fledging, switching later to larger prey. The stable isotope analysis indicated that the Grey Heron diet did not change significantly during the fledging period of their juveniles. The calculated trophic levels of Great Cormorants and Grey Herons were similar (3.55 ± 0.12 and 3.57 ± 0.41, respectively). The isotopic values in Grey Herons and Great Cormorants were 14.6–16.0‰ for δ15N and –27.3–(–24.9)‰ for δ13C. These values are typical of piscivorous bird species mostly feeding in freshwater bodies, i. e. in the Curonian Lagoon. The δ15N values found in the feathers of Long-tailed Ducks ranged from 7.7 to 13.9‰ and the δ13C values ranged from –33.6 to –24.9‰ showing high variation of feeding habitats during the moulting period: from freshwater to marine environment.

Distribution patterns of wintering sea ducks in relation to the North Atlantic Oscillation and local environmental characteristics

Twelve species of North American sea ducks (Tribe Mergini) winter off the eastern coast of the United States and Canada. Yet, despite their seasonal proximity to urbanized areas in this region, there is limited information on patterns of wintering sea duck habitat use. It is difficult to gather information on sea ducks because of the relative inaccessibility of their offshore locations, their high degree of mobility, and their aggregated distributions. To characterize environmental conditions that affect wintering distributions, as well as their geographic ranges, we analyzed count data on five species of sea ducks (black scoters Melanitta nigra americana, surf scoters M. perspicillata, white-winged scoters M. fusca, common eiders Somateria mollissima, and long-tailed ducks Clangula hyemalis) that were collected during the Atlantic Flyway Sea Duck Survey for ten years starting in the early 1990s. We modeled count data for each species within ten-nautical-mile linear survey segments using a zero-inflated negative binomial model that included four local-scale habitat covariates (sea surface temperature, mean bottom depth, maximum bottom slope, and a variable to indicate if the segment was in a bay or not), one broad-scale covariate (the North Atlantic Oscillation), and a temporal correlation component. Our results indicate that species distributions have strong latitudinal gradients and consistency in local habitat use. The North Atlantic Oscillation was the only environmental covariate that had a significant (but variable) effect on the expected count for all five species, suggesting that broad-scale climatic conditions may be directly or indirectly important to the distributions of wintering sea ducks. Our results provide critical information on species-habitat associations, elucidate the complicated relationship between the North Atlantic Oscillation, sea surface temperature, and local sea duck abundances, and should be useful in assessing the impacts of climate change on seabirds.

Inter- and intraclutch variation in egg mercury levels in marine bird species from the Canadian Arctic

Mercury (Hg) is a toxic metal that has been of increasing concern in the Canadian Arctic. We measured total Hg in eggs of three marine birds (Arctic terns Sterna paradisaea, common eiders Somateria mollissima borealis, long-tailed ducks Clangula hyemalis) that breed in the Canadian Arctic, to compare Hg laying order effects from the same clutch and to examine Hg among species. Early-laid eggs of all three species had 24–48% higher Hg concentrations than late laid eggs. Arctic terns had approximately twice the concentration of Hg in their eggs as the two duck species, and Hg in eider eggs from the High Arctic was higher than Hg in eggs from the Low Arctic. Higher Hg in tern eggs was consistent with this species occupying a higher trophic position in marine food webs, as indicated by stable nitrogen isotope ( δ 15N) values. The egg-laying sequence may need to be considered for Hg biomonitoring studies where small samples sizes are planned, and early eggs may be preferable for such studies since early eggs may be more representative of potential maximum levels of Hg in the marine food webs.