Gregory Robertson

Relatively little attention has been paid to the occurrence of anthropogenic debris found in coastal species, especially waterfowl. We examined the incidence of ingested plastic and metal in three waterfowl species wintering in Atlantic Canada: American black ducks (Anas rubripes) and mallards (A. platyrhynchos), two species that use marine and freshwater coastal habitats for foraging in the winter, and common eider (Somateria mollissima), a coastal marine species that feeds on intertidal and subtidal benthic organisms. Plastic was found in the stomachs of 46.1% (6/13) of mallards and 6.9% (6/87) of black ducks, the first report of ingested anthropogenic debris in these species, while 2.1% (1/48) of eider stomachs contained plastic. Metal was found in the stomachs of 30.8% (4/13) of mallards, 2.3% (2/87) of black ducks, and in 2.1% (1/48) of eiders. Our results indicate that species using coastal marine and freshwater environments are exposed to and ingest anthropogenic debris.

Common (Uria aalge) and Thick-billed Murres (Uria lomvia) are apex predators in the North Atlantic Ocean, and are also subject to a traditional hunt in Newfoundland and Labrador during the winter months, along with small numbers of illegally harvested Razorbills (Alca torda). Because of their high trophic position, auks are at risk from high contaminant burdens that bioaccumulate and biomagnify, and could therefore pose a toxicological risk to human consumers. We analysed trace element concentrations from breast muscle of 51 auks collected off Newfoundland in the 2011-2012 hunting season. There were few differences in contaminant concentrations among species. In total, 14 (27%) exceeded Health Canada or international guidelines for arsenic, lead, or cadmium; none exceeded guidelines for mercury. Cadmium concentrations >0.05μg/g have persisted in Newfoundland murres for the last 25 years. We urge the integration of this consumptive harvest for high-trophic marine predators into pe...

ABSTRACT The entire world population of the Glaucous Gull Larus hyperboreus breeds in the circumpolar Arctic. Some local populations appear to be declining significantly. In this paper, we summarize the current state of knowledge on Glaucous Gull populations and trends. The total Arctic population is estimated at 138 600 to 218 600 breeding pairs (277 200 to 437 200 breeding individuals) distributed among at least 2768 colonies (many not documented). Population declines may be attributable to egg harvest, contaminants, or food shortages, but other factors operating outside the breeding season should not be excluded. We recommend collaborative conservation efforts that will include better population estimates in most countries, as well as standardized monitoring programs.

We developed a stochastic, stage-based, matrix-projection population model to assess population viability and estimate the impact of mortality caused by hunting, illegal and incidental to the murre (Uria sp.) hunt, and fox (Alopex lagopus) predation on Razorbill (Alca torda) populations breeding on the Gannet Islands, Labrador, the "affected" population, and Machias Seal Island, New Brunswick, the "unaffected" population. We estimated

Abstract. The timing of pair formation varies with- in and among,species of ducks. In this study we,doc- umented,the chronology,of pair formation,in a popu- lation of wintering Harlequin Ducks (Histrionicus his- trionicus) in southwestern,British Columbia. Harlequin Ducks began,forming,pair bonds,in October and over half of the females,were,paired by December. This timing is much,earlier than other ducks,of similar size. A segment of this

ABSTRACT Stable isotope (δ15N, δ13C) analysis of primary feathers and muscle tissue of Dovekies Alle alle collected on Newfoundland beaches following an oil spill in early winter 2004 were used to investigate age-related variation in trophic niche during summer, fall and early winter. Observed δ15N values of adults were significantly higher than those of sub-adults during fall moult and hatch-year birds during summer. Strong segregation of δ13C and δ15N values of hatch-year birds into two distinct groups during summer may indicate differences in the colony of origin. Similarly, a wide range of δ13C values for adult and sub-adult Dovekies during fall may indicate differences in moulting areas. In early winter, the δ13C values of all age classes overlapped, with relatively depleted δ13C values (-20.0 ± 0.4‰) characteristic of offshore waters. Age-class overlap in δ15N values (+12.2 ± 0.4‰) likely reflects a common diet of Calanus finmarchicus, the most abundant copepod in near-surface waters on the Newfoundland–Labrador shelf in winter. Our results suggest that Dovekies from different age classes and potentially breeding regions overlap on their wintering grounds where they rely on a common Calanus prey. Consequently, future climate-driven shifts in the meso-zooplankton communities in the North Atlantic have potentially large-scale population consequences for this abundant planktivore.

ABSTRACT Timing reproduction to overlap with peak prey availability is vital to success for many species. This may be especially true for species that rely on one or a few prey species that exhibit strong seasonal peaks in abundance. Any mismatch must be mediated by parents that provision offspring through flexible behavioral changes within the bounds of their physiological tolerances. In Newfoundland, common murre Uria aalge breeding coincides with the inshore movement of capelin Mallotus villosus—their primary prey—such that peak prey availability overlaps with chick-rearing, the most energy demanding phase of breeding. We use colony-based observations and temperature-depth recorders to track the behavioral responses of murres to temporal match and mismatch with capelin availability. Activity budgets, daily energy expenditure (DEE) and chick-provisioning rates were constant across years when chick and capelin timing matched. However, when capelin were late, despite increasing diving effort and DEE, parents delivered fewer fish to chicks per day and reduced breeding success was observed. While parents partially buffered the effects of variable capelin abundance by reducing co-attendance time (time spent at the colony with mates) and increasing foraging time, physiological constraints on energy output likely limited their ability to maintain chick-provisioning rates in a mismatch year. Such responses could have demographic consequences if ocean climate changes decouple the timing of chick-rearing and prey availability.

This species account discusses: distinguishing characteristics, distribution, systematics, migration, habitat, food habits, vocalizations, behavior (locomotion, maintenance, agonistic, spacing, sexual, social and interspecific), predation, breeding (phenology, nest site, nest, ...

We provide the first report on winter concentrations of 32 trace metals from dovekies (Alle alle), a small, Arctic seabird that has a seasonal shift in diet from small zooplankton in the breeding season to larger zooplankton and small fish in the non-breeding season. Concentrations of selected trace elements, as well as stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope concentrations for a sample of 25 dovekies, were similar between adult males and females, and there was evidence that dovekies feeding at higher trophic levels had higher hepatic Hg. We also found plastic debris in nine of 65 (14%) gizzards examined. Our study helps provide a more complete picture of the foraging ecology and contaminant profile of dovekies, an important species in Arctic marine food webs.

Page 1. Autumn and Winter Diet of Long-tailed Duck in the Belcher Islands, Nunavut, Canada SARAH E. JAMIESON1'2, GREGORYJ. ROBERTSON3 AND H. GRANT GILCHRIST4 'Department of Biology, Memorial University of Newfoundland, St. ...

ABSTRACT Sustainable harvest, the extraction of game without affecting population viability, is a desirable approach to the use of wildlife. However, overharvest has been responsible for the decline of many wildlife populations globally, so there is an urgent need to balance human requirements while avoiding the severe depletion of wild populations. Northern common eiders Somateria mollissima borealis are heavily hunted in Canada and Greenland, but the effect of this intensive harvest has not been examined. We developed a population model to investigate the sustainability of the reported harvest, which consisted of two wintering areas in Greenland and Atlantic Canada and three breed-ing populations. The model indicated that harvest in Atlantic Canada was sustainable, but a number of conditions could lead to slow declines. In contrast, the annual winter harvest of 55,000-70,000 eiders reported during 1993-2000 in Greenland was not sustainable, and this conclusion held under a wide range of alternate conditions. The model indicated that harvest during late winter may have a greater effect on populations than harvest in early winter. We further refined the model to assume that at some low population level the success of hunters would decline and that harvest became a function of population size (a rate). This scenario had the expected and undesir-able result of stabilizing populations at very low levels. Overall, our model suggests that the high harvest reported in Greenland during 1993-2000 endangers the sustainable use of the northern common eider population and that man-agement actions are required. Common eider harvest levels in Greenland should be reduced by at least 40% of the 1993-2000 levels to stop projected declines, and allow for recovery of the decimated Greenland breeding population. Encouragingly, new hunting regulations were introduced in Greenland in 2002-2004, and harvest levels appear to be decreasing. If these harvest reductions continue, our population model could be used to re-evaluate the status of populations in the two countries.

Abstract In waterfowl, the male costs and female benefits hypothesis considers that the timing of pairing will depend on the balance between the costs and benefits for each sex. Females may benefit by increasing their access to food and social status, and by ...

A comparison of commonly occurring metazoan parasites in the digestive tract was made between common eiders, Somateria mollissima, that were contaminated with oil and reference birds confiscated from illegal hunting. There was a greater number of commonly occurring parasites and their abundance in reference than in oiled eiders. Except for an acanthocephalan, Polymorphus botulus, which was embedded in the wall of the intestinal tract, most of the other taxa of parasites, including trematodes, cestodes and nematodes, were probably voided from the birds following ingestion of oil. Reference eiders harboured fewer species and a substantially lower mean abundance of parasites than those studied in Newfoundland and Labrador more than four decades ago; this may be a signal of a changing prey base or an increase in prey availability as winter ice cover continues to decline.

Corticosterone (CORT) levels in seabirds fluctuate across breeding stages and in different foraging conditions. Here we use a ten-year data set to examine whether CORT levels in Atlantic puffins differ in years with high or low availability of capelin, the preferred forage species. Female puffins had higher CORT levels than males, possibly related to cumulative costs of egg production and higher parental investment. Puffins had higher CORT levels and body mass during pre-breeding than during chick rearing. Yearly mean chick growth rates were higher in years when adults had higher body mass and in years where adults brought chicks a lower percentage of non-fish (invertebrates/larval fish) food. Unlike most results from seabird species with shorter chick-rearing periods, higher CORT levels in puffins were not associated with lower capelin abundance. Puffins may suppress CORT levels to conserve energy in case foraging conditions improve later in the prolonged chick-rearing period. Alternatively, CORT levels may be lowest both when food is very abundant (years not in our sample) or very scarce (e.g., 2009 in this study), and increase when extra foraging effort will increase foraging efficiency (most years in this study). If these data primarily represent years with medium to poor foraging, it is possible that CORT responses to variation in foraging conditions are similar for puffins and other seabirds.

Many species of waterfowl form pair bonds during the nonbreeding season, yet current descriptions of mating systems and patterns of philopatry in waterfowl focus on the breeding grounds. We studied wintering Harlequin Ducks (Histrionicus histrionicus) in southwestern British ...