Sea Ducks Research Articles

Collision and displacement vulnerability to offshore wind energy infrastructure among marine birds of the Pacific Outer Continental Shelf

Marine birds are vulnerable to collision with and displacement by offshore wind energy infrastructure (OWEI). Here we present the first assessment of marine bird vulnerability to potential OWEI in the California Current System portion of the U.S. Pacific Outer Continental Shelf (POCS). Using population size, demography, life history, flight heights, and avoidance behavior for 62 seabird and 19 marine water bird species that occur in the POCS, we present and apply equations to calculate Population Vulnerability, Collision Vulnerability, and Displacement Vulnerability to OWEI for each species. Species with greatest Population vulnerability included those listed as species of concern (e.g., Least Tern [Sternula antillarum], Marbled Murrelet [Brachyramphus marmoratus], Pink-footed Shearwater [Puffinus creatopus]) and resident year-round species with small population sizes (e.g., Ashy Storm-Petrel [Oceanodroma homochroa], Brandt's Cormorant [Phalacrocorax penicillatus], and Brown Pelican [Pelecanus occidentalis]). Species groups with the greatest Collision Vulnerability included jaegers/skuas, pelicans, terns and gulls that spend significant amounts of time flying at rotor sweep zone height and don't show macro-avoidance behavior (avoidance of entire OWEI area). Species groups with the greatest Displacement Vulnerability show high macro-avoidance behavior and low habitat flexibility and included loons, grebes, sea ducks, and alcids. Using at-sea survey data from the southern POCS, we combined species-specific vulnerabilities described above with at-sea species densities to assess vulnerabilities spatially. Spatial vulnerability densities were greatest in areas with high species densities (e.g., near-shore areas) and locations where species with high vulnerability were found in abundance. Our vulnerability assessment helps understand and minimize potential impacts of OWEI infrastructure on marine birds in the POCS and could inform management decisions.

Sample size considerations for satellite telemetry and animal distributions

ABSTRACTSatellite telemetry is a powerful tool used to follow animals through their annual life cycle, informing the understanding of behavior and distribution of many species. Because boreal‐ and arctic‐nesting North American sea duck populations are challenging to survey, satellite telemetry is important for describing breeding distributions and identifying breeding population structure. Accurate knowledge of breeding distributions is needed for effective habitat and harvest management, but satellite telemetry is expensive so it is important to consider the effort necessary to accurately map breeding distributions. We construct 3 theoretical breeding distributions using existing telemetry data from 3 species of sea ducks, Barrow's goldeneye (Bucephala islandica), surf scoter (Melanitta perspicillata), and black scoter (M. americana), by fitting kernel densities to approximate breeding locations of individual birds. Then we determined the minimum sample size needed to approximate these theoretical breeding distributions by assessing the overlap between breeding densities simulated by sampling from the distributions and the theoretical breeding densities. Diminishing information gains with additional effort (i.e., <1–5% improvement in prediction) were reached with sample sizes ranging from 80 to 130. Sea duck mortality, transmitter failure, and exclusion of non‐breeding individuals resulted in an effective sample size smaller than the number of birds originally marked. For the cases we considered, obtaining breeding locations for 80–130 individuals would require marking 11–41% more birds than the sample size goal. Thus, although satellite telemetry provides valuable information on sea duck populations, our analysis suggests that accurately estimating the extent and relative use of breeding habitats requires substantial investment. © 2018 The Wildlife Society.

Sediment organic carbon integrates changing environmental conditions to predict benthic assemblages in shallow Arctic seas

Abstract In marine spatial planning, conserving adequate habitats and the food webs they support requires delineating habitats and projecting future trends. For bottom‐feeding marine birds and mammals, repeated benthic sampling over large areas to document changes and to develop predictive models of prey dispersion is quite costly. More easily monitored variables that relate strongly to the biomass and structure of benthic assemblages, and are more readily predicted from physical models of climate change, would facilitate planning efforts. The organic carbon (OC) content of sediments integrates diverse physical and biotic processes, and can be less variable over time than primary production, salinity, temperature, or position of water masses. Sediment OC further subsumes inputs at the base of food webs that can limit carbon flows to higher taxa. For the northern Bering Sea, this study explored the utility of sediment OC as a predictor of benthic assemblage types. Cluster analysis and multi‐dimensional scaling distinguished three main types along a gradient of sediment OC. The assemblage for highest sediment OC had a much greater biomass of brittlestars, diverse marine worms, and two mid‐sized, thinner‐shelled bivalves selected as prey by diving sea ducks. The assemblage for lowest sediment OC lacked brittlestars, had a much greater biomass of amphipods sought by gray whales (Eschrichtius robustus), and had a much higher biomass of two often larger or thicker‐shelled bivalves commonly targeted by walruses (Odobenus rosmarus). Areas of exceptionally low sediment OC tended towards dominance by sand dollars with low foraging value. Our study shows that sediment OC has promise as a proxy for monitoring and predicting changes in important prey assemblages in a given region. Models that link predicted hydrographic patterns to lateral advection of phytodetritus, and the resulting sediment OC, may further allow the use of physical climate models to project the future dispersion of benthic habitats for endothermic predators.

Spatial Organization of the Epithelial Structures in the Bill Tip Organ of Waterfowl (Anseriformes, Aves)

The spatial organization of the bill tip organ in waterfowl is studied in 327 specimens from 35 species from the Anseriform order, including geese, swans, seaducks, shelducks, dabbling, and diving ducks. Two types of tactile epithelial formations, sensillar and asensillar, are revealed on the tips of the upper and lower jaws. The number of the mandibular formations always exceeds that of the maxillary. The combinations of these indicators differ significantly among the majority of the studied species. The studied species can be divided into three types based on combinations of the number of upper and lower tactile formations according to different foraging techniques: grazing (geese, swans, sheldgeese), pursuit diving (sea ducks), and dabbling (pochards, shelducks, dabbling ducks). The formation density per square mm correlates with the asymmetry of the bill tip organ (r = 0.55; p < 0.01; n = 327). The correlation is the greatest in dabbling species. The probable function of the bill tip organ, in addition to location and analyse of food particles, lies in the fact that dabbling species can communicate with each other via motions in the course of food intake. This helps them to save time and to optimize their individual distances when feeding in darkness.

TetratrichomonasandTrichomonasspp.-Associated Disease in Free-Ranging Common Eiders (Somateria mollissima) from Wellfleet Bay, MA and Description of ITS1 Region Genotypes

During an outbreak of Wellfleet Bay virus (WFBV) in common eiders ( Somateria mollissima) from the Cape Cod region of Massachusetts, several birds were diagnosed with trichomonosis consisting of multiple trichomonad species. Six birds were examined, with trichomonads found in ceca in four birds and associated typhlitis in three of these four birds. PCR and DNA sequencing utilizing trichomonad-specific primers targeting the ITS1 region of the ribosomal DNA (rDNA) revealed the presence of Tetratrichomonas gallinarum in the gastrointestinal tracts of five birds and Trichomonas spp. in the livers of two birds, one of which had a dual Te. gallinarum-Trichomonas gallinae infection. Sequence analysis revealed no variation between Te. gallinarum sequences whereas the ITS1 sequences obtained from the other Trichomonas spp. demonstrated the presence of multiple genotypes. One sequence had 100% identity to a Trichomonas sp. previously isolated from a Cooper's hawk ( Accipiter cooperii) and the other sequence was 100% identical to a previously described Tr. gallinae isolate obtained from a Pacific Coast band-tailed pigeon ( Patagioenas fasciata monilis). These findings suggest Te. gallinarum and other Trichomonas spp. possibly contributed to morbidity and mortality in this species. Furthermore, to the authors' knowledge, this is the first report of trichomonad-associated disease in a free-ranging sea duck.

Sustainable management of migratory European ducks: finding model species

Eurasian migratory duck species represent a natural resource shared between European countries. As is evident throughout human harvest history, lack of coordinated management and monitoring at appropriate levels often leads to ‘the tragedy of the commons’, where shared populations suffer overexploitation. Effective management can also be hampered by poor understanding of the factors that limit and regulate migratory populations throughout their flyways, and over time. Following decades of population increase, some European duck populations now show signs of levelling off or even decline, underlining the need for more active and effective management. In Europe, the existing mechanisms for delivering effective management of duck populations are limited, despite the need and enthusiasm for establishing adaptive management (AM) schemes for wildlife populations. Existing international legal agreements already oblige European countries to sustainably manage migratory waterbirds. Although the lack of coordinated demographic and hunting data remains a challenge to sustainable management planning, AM provides a robust decision‐making framework even in the presence of uncertainty regarding demographic and other information. In this paper we investigate the research and monitoring needs in Europe to successfully apply AM to ducks, and search for possible model species, focusing on freshwater species (in contrast to sea duck species) in the East Atlantic flyway. Based on current knowledge, we suggest that common tealAnas crecca,Eurasian wigeonMareca penelopeand common goldeneyeBucephala clangularepresent the best species for testing the application of an AM modelling approach to duck populations in Europe. Applying AM to huntable species with relatively good population data as models for broader implementation represents a cost effective way of starting to develop AM on a European flyway scale for ducks, and potentially other waterbirds in the future.

Changes in nesting success and breeding abundance of Spectacled Eiders Somateria fischeri in the Chaun Delta, Chukotka, Russia, 2003–2016

The Spectacled Eider Somateria fischeri is a rare sea duck confined to breeding in the Yukon–Kuskokwim Delta and Arctic coasts of Alaska and Russia. Almost nothing is known about its status and breeding biology in the Russian Arctic. Stratified systematic nest searches were conducted annually of Spectacled Eider nests on Ayopechan Island in the Chaun Delta, Arctic Russia during 2003–2016. Mean nest densities were stable during 2003–2009 but declined by 8.0% per annum during 2009–2016. Mean clutch size and annual female survival did not change over the same period, during which time annual nest survival and hatching success declined significantly. A simple three age-class matrix model estimated annual asymptotic population growth rate (λ) using observed fecundity from the beginning (1.1 hatched chick per female, λ = 0.864) and end (0.45 hatched chick per female, λ = 0.828) of the study period. This confirmed that to stabilize this population required three immigrant recruits for every local recruit at the beginning of the study and nine towards the end. Declines in annual nest survival appear correlated with (i) declines in nesting Sabine’s Gulls Xema sabini and Arctic Terns Sterna paradisaea with which nesting Spectacled Eiders associated and may have gained protection from predators, and (ii) marginally significant increases in large gull and mammalian predators at the site. Should current trends in nest density and fecundity continue, the survival of this breeding Spectacled Eider population is in jeopardy.

Mitogenomics supports an unexpected taxonomic relationship for the extinct diving duck Chendytes lawi and definitively places the extinct Labrador Duck

Chendytes lawi, an extinct flightless diving anseriform from coastal California, was traditionally classified as a sea duck, tribe Mergini, based on similarities in osteological characters. We recover and analyze mitochondrial genomes of C. lawi and five additional Mergini species, including the extinct Labrador Duck, Camptorhynchus labradorius. Despite its diving morphology, C. lawi is reconstructed as an ancient relictual lineage basal to the dabbling ducks (tribe Anatini), revealing an additional example of convergent evolution of characters related to feeding behavior among ducks. The Labrador Duck is sister to Steller’s Eider which may provide insights into the evolution and ecology of this poorly known extinct species. Our results demonstrate that inclusion of full length mitogenomes, from taxonomically distributed ancient and modern sources can improve phylogeny reconstruction of groups previously assessed with shorter single-gene mitochondrial sequences.

Multi-Year Counts of Sea Ducks and Gulls In the Nearshore of the Pribilof Islands, Alaska

Abstract Monitoring avian populations over both the reproductive and non-reproductive seasons is required to better understand population changes. Obtaining baseline data in remote sites, however, is often difficult during the non-breeding season, especially in ice-driven ecosystems. We determined annual changes in numbers of over-wintering sea duck and large-bodied gull species and identified their main areas of concentration at one of the Pribilof Islands (St. Paul) in the Bering Sea. Formally trained local citizens undertook weekly counts using standardized methods over 3 non-breeding seasons (2008–2009; 2009–2010; 2010–2011) from late autumn to early spring. Sea ducks and large-bodied gulls were present nearshore in considerable numbers from November to January, and maximum counts usually occurred between February and March when sea-ice cover is at its maximum near the Pribilof Islands. We found that one-time counts would underestimate some species (Bufflehead, King Eider, Harlequin Duck), their numbe...

Unusual Foraging Behavior By Surf Scoters (Melanitta perspicillata) In the Swash Zone

Surf Scoter (Melanitta perspicillata), a sea duck that winters commonly along the coast of the Pacific Northwest states, was observed exhibiting unusual foraging behavior in the swash zone of a beach on the Point Reyes Peninsula, California, in mid-January of 2015. This note reviews the literature involving scoter foraging behavior, discusses the likely prey items targeted, and the potential risks posed by such behavior.

Identifying demographic and environmental drivers of recruitment and population growth in a cavity‐nesting sea duck population

Traits with the greatest proportional effects on fitness are typically conserved, and traits with larger temporal variation frequently play a dominant role in population dynamics. We examined recruitment patterns and population growth in common goldeneyes Bucephala clangula (hereafter goldeneye), using Pradel mark–recapture models from a long‐term nest box study (1997–2010). Our objectives were to estimate recruitment (f ) and population growth (λ) relative to recruitment origin group (in‐situ or unknown), investigate environmental and density dependent effects on these parameters, and evaluate potential immigration patterns. We detected group‐specific differences for f (in‐situ: 0.47 ± 0.13 SE, unknown: 0.31 ± 0.04), and the proportion of boxes occupied by goldeneyes the year prior to recruitment had a significant negative effect on recruitment for the in‐situ group (β = –1.04; 85% CI –1.29, –0.78), and a positive effect for the unknown group (β = 0.45; 85% CI 0.30, 0.61). The negative box occupancy effect in the year prior to recruitment, when in‐situ yearling goldeneyes prospect for potential nest sites, suggests that local nesting densities may limit recruitment of locally hatched females. We identified two competitive models for λ, which averaged 1.04 ± 0.03 and included interactions between recruitment origin group and a linear temporal trend, and the proportion of ducklings marked two years prior. By evaluating all levels of marking effort on λ, we determined that even if all hatched ducklings were marked in a given year, the resulting in‐situ λ was consistently lower than all observed population‐level λs during the study, indicating that individuals produced outside of study area nest boxes contributed to λ. Though female goldeneyes are considered highly philopatric, our results suggest that female natal and breeding dispersal may be more prevalent than previously thought, and the spatial scale at which these processes occur requires further investigation.

High-resolution sea duck distribution modeling: Relating aerial and ship survey data to food resources, anthropogenic pressures, and topographic variables

ABSTRACT Anthropogenic developments in marine coastal zones potentially overlap with areas of conservation interest, including important areas for birds. Ideally, spatial patterns of species abundance should be considered at ecologically relevant spatial resolutions (high resolutions) to inform spatial planning and environmental assessments. Most planning so far, however, has relied on coarse-resolution distribution maps from atlas projects or models often based on limited datasets (few surveys), and relationships with environmental variables have rarely been taken into account, leaving many studies and recommendations vulnerable to criticism. We therefore combined the strengths of a detailed database of spatially explicit aerial and ship surveys with high-resolution environmental predictors and species distribution models to predict detailed density patterns for 3 sea duck species, as part of an environmental impact assessment (EIA) in the southern Baltic Sea. We also compared the results from 2 differen...

Evaluation of harvest and information needs for North American sea ducks.

Wildlife managers routinely seek to establish sustainable limits of sport harvest or other regulated forms of take while confronted with considerable uncertainty. A growing body of ecological research focuses on methods to describe and account for uncertainty in management decision-making and to prioritize research and monitoring investments to reduce the most influential uncertainties. We used simulation methods incorporating measures of demographic uncertainty to evaluate risk of overharvest and prioritize information needs for North American sea ducks (Tribe Mergini). Sea ducks are popular game birds in North America, yet they are poorly monitored and their population dynamics are poorly understood relative to other North American waterfowl. There have been few attempts to assess the sustainability of harvest of North American sea ducks, and no formal harvest strategy exists in the U.S. or Canada to guide management. The popularity of sea duck hunting, extended hunting opportunity for some populations (i.e., special seasons and/or bag limits), and population declines have led to concern about potential overharvest. We used Monte Carlo simulation to contrast estimates of allowable harvest and observed harvest and assess risk of overharvest for 7 populations of North American sea ducks: the American subspecies of common eider (Somateria mollissima dresseri), eastern and western populations of black scoter (Melanitta americana) and surf scoter (M. perspicillata), and continental populations of white-winged scoter (M. fusca) and long-tailed duck (Clangula hyemalis). We combined information from empirical studies and the opinions of experts through formal elicitation to create probability distributions reflecting uncertainty in the individual demographic parameters used in this assessment. Estimates of maximum growth (rmax), and therefore of allowable harvest, were highly uncertain for all populations. Long-tailed duck and American common eider appeared to be at high risk of overharvest (i.e., observed harvest < allowable harvest in 5–7% and 19–26% of simulations, respectively depending on the functional form of density dependence), whereas the other populations appeared to be at moderate risk to low risk (observed harvest < allowable harvest in 22–68% of simulations, again conditional on the form of density dependence). We also evaluated the sensitivity of the difference between allowable and observed harvest estimates to uncertainty in individual demographic parameters to prioritize information needs. We found that uncertainty in overall fecundity had more influence on comparisons of allowable and observed harvest than adult survival or observed harvest for all species except long-tailed duck. Although adult survival was characterized by less uncertainty than individual components of fecundity, it was identified as a high priority information need given the sensitivity of growth rate and allowable harvest to this parameter. Uncertainty about population size was influential in the comparison of observed and allowable harvest for 5 of the 6 populations where it factored into the assessment. While this assessment highlights a high degree of uncertainty in allowable harvest, it provides a framework for integration of improved data from future research and monitoring. It could also serve as the basis for harvest strategy development as management objectives and regulatory alternatives are specified by the management community.

Variation in abundance of Pacific Blue Mussel (Mytilus trossulus) in the Northern Gulf of Alaska, 2006–2015

Mussels are conspicuous and ecologically important components of nearshore marine communities around the globe. Pacific blue mussels (Mytilus trossulus) are common residents of intertidal habitats in protected waters of the North Pacific, serving as a conduit of primary production to a wide range of nearshore consumers including predatory invertebrates, sea ducks, shorebirds, sea otters, humans, and other terrestrial mammals. We monitored seven metrics of intertidal Pacific blue mussel abundance at five sites in each of three regions across the northern Gulf of Alaska: Katmai National Park and Preserve (Katmai) (2006–2015), Kenai Fjords National Park (Kenai Fjords) (2008–2015) and western Prince William Sound (WPWS) (2007–2015). Metrics included estimates of: % cover at two tide heights in randomly selected rocky intertidal habitat; and in selected mussel beds estimates of: the density of large mussels (≥ 20 mm); density of all mussels > 2 mm estimated from cores extracted from those mussel beds; bed size; and total abundance of large and all mussels, i.e. the product of density and bed size. We evaluated whether these measures of mussel abundance differed among sites or regions, whether mussel abundance varied over time, and whether temporal patterns in abundance were site specific, or synchronous at regional or Gulf-wide spatial scales. We found that, for all metrics, mussel abundance varied on a site-by-site basis. After accounting for site differences, we found similar temporal patterns in several measures of abundance (both % cover metrics, large mussel density, large mussel abundance, and mussel abundance estimated from cores), in which abundance was initially high, declined significantly over several years, and subsequently recovered. Averaged across all sites, we documented declines of 84% in large mussel abundance through 2013 with recovery to 41% of initial abundance by 2015. These findings suggest that factors operating across the northern Gulf of Alaska were affecting mussel survival and subsequently abundance. In contrast, density of primarily small mussels obtained from cores (as an index of recruitment), varied markedly by site, but did not show meaningful temporal trends. We interpret this to indicate that settlement was driven by site-specific features rather than Gulf wide factors. By extension, we hypothesize that temporal changes in mussel abundance observed was not a result of temporal variation in larval supply leading to variation in recruitment, but rather suggestive of mortality as a primary demographic factor driving mussel abundance. Our results highlight the need to better understand underlying mechanisms of change in mussels, as well as implications of that change to nearshore consumers.

Spatial variation in polycyclic aromatic hydrocarbon exposure in Barrow's goldeneye (Bucephala islandica) in coastal British Columbia

Barrow's goldeneyes are sea ducks that winter throughout coastal British Columbia (BC). Their diet consists primarily of intertidal blue mussels, which can accumulate PAHs; accordingly, goldeneyes may be susceptible to exposure through contaminated prey. In 2014/15, we examined total PAH concentrations in mussels from undeveloped and developed coastal areas of BC. At those same sites, we used EROD to measure hepatic CYP1A induction in goldeneyes. We found higher mussel PAH concentrations at developed coastal sites. Regionally, goldeneyes from southern BC, which has relatively higher coastal development, had higher EROD activity compared to birds from northern BC. Our results suggest goldeneyes wintering in coastal BC were exposed to PAHs through diet, with higher exposure among birds wintering in coastal areas with greater anthropogenic influence. These results suggest the mussel-goldeneye system is suitable as a natural, multi-trophic-level indicator of contemporary hydrocarbon contamination occurrence and exposure useful for establishing oil spill recovery endpoints.

Life history patterns, individual heterogeneity, and density dependence in breeding common goldeneyes of the northern boreal forest

Life history patterns and their associated tradeoffs influence population dynamics, as they determine how individuals allocate resources among competing demographic traits. Here we examined life history strategies in common goldeneyes Bucephala clangula (hereafter goldeneye), a cavity‐nesting sea duck, in the northern boreal forest of interior Alaska, USA. We used multistate capture–mark–recapture models to estimate adult survival, breeding probability, first‐year survival, and recruitment probability using a long‐term nest box study (1997–2010). We detected annual variation in adult survival, which varied from 0.74 ± 0.12 (SE) to 0.93 ± 0.06. In contrast, breeding probability remained relatively high and invariant (0.84 ± 0.11) and was positively related to individual nest success the year prior. Nonbreeding individuals in one year were more likely to remain a nonbreeder, than attempt to breed the following year. First‐year survival decreased with smaller residual duckling mass and larger brood sizes. Probability of recruitment into the breeding population conditioned on survival was constant during the study (0.96 ± 0.06), and did not vary among ages 2–5 yr‐old. Overall, goldeneyes exhibited high, but somewhat variable, adult survival, and high breeding and recruitment probabilities, which is consistent with observed patterns in bet‐hedging species that breed annually in high quality breeding environments, but whose reproductive output is often influenced by stochastic events. Demographic estimates from this study are among the first for goldeneyes within Alaska. Life history patterns are known to vary geographically, therefore, we recommend further examination of life history patterns within the distribution of goldeneyes.

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.

Birds of Brier Island

Brier Island, Nova Scotia, Canada, at the southwestern entrance to the Bay of Fundy, has been known for years as a prime birding destination. It combines access to unusually rich gatherings of pelagic birds, the chance of seeing rarities in greater frequency than almost anywhere else in the province, and the spectacle of large volume land bird migrations. The island lies at the intersection of migratory routes along the east coast of North America. Because of intense oceanic turbulence in the adjacent shallow water, which is in close proximity to deeper water, rich feeding is available for nearshore seabirds and pelagic species. Of the 470+ species recorded from the Province of Nova Scotia as a whole, 355 have been recorded from Brier Island. Many of these are vagrants, mainly of western or southern origin in North America; others are common passage migrants that visit the island briefly in very large numbers, especially in autumn. Apart from possible vagrants in spring and fall, the island is noted for the abundance of passerine migrants in autumn, a striking hawk migration in September and October, late-summer gatherings of phalaropes, shearwaters, and storm petrels, and an abundance of overwintering alcids, loons, grebes, and sea ducks in winter. The island has been the site of bird-banding activity and of Christmas counts for more than 50 years. We provide an introduction to the physiography, geology, physical geography, oceanography, and ecology of the island, along with a list of the breeding birds, a comparison with Grand Manan, New Brunswick, an extensively annotated list of the birds plausibly reported from the island to the middle of 2011, describing occurrence, seasonality, and abundance of all species, and a checklist of the birds of the island. Species occurrence data available via the OBIS Canada data repository http://ipt.iobis.org/obiscanada/resource?r=brierisland_birds

The North American Sea Ducks

The 21 species of sea ducks are one of the larger subgroups (Tribe Mergini) of the waterfowl family Anatidae, and the 16 species (one historically extinct) that are native to North America represent the largest number to be found on any continent, and also the largest number of endemic sea duck species native to any continent.

Life cycle and biology of Tristriata anatis (Digenea: Notocotylidae): morphological and molecular approaches.

Notocotylids are common digeneans parasitising birds and mammals. They have a two-host life cycle with cercariae encysting in the open. Particular life cycles remain unknown for majority of notocotylid species, including a common parasite of sea ducks Tristriata anatis. Here we resolve the life cycle of T. anatis by means of D2 LSU, ITS1 and CO1 DNA sequence analysis, showing that the first intermediate hosts for this species are periwinkles Littorina spp. Morphological descriptions of rediae and cercariae are provided for the first time, and we also supplement the existing morphological data on adults. Apart from differential diagnosis, we discuss some features of cercariae and rediae biology, geographical distribution and host range. Our molecular data confirm that genus Tristriata is monotypic and that T. anatis has circumpolar distribution. CO1 sequence analysis has shown that isolation exists between the Atlantic and Pacific populations of T. anatis, suggesting that there are geographical races. We suppose that their formation may be linked to the Last Ice Age events, when trans-Arctic bird migrations ceased and periwinkle ranges shrunk. These made transfer of parasites across the Arctic impossible, and it still has not resumed. We discuss the possible influence of host vagility and adults' lifespan on digeneans' potential for geographical colonisation.