Rapid increase in contaminant burdens following loss of body condition in canvasbacks (Aythya valisineria) overwintering on the Lake St. Clair region of the Great Lakes.

Overwintering canvasbacks were collected in the Lake St. Clair region of the Great Lakes in the winter of 2008/09 and livers were analyzed for organochlorines, mercury (Hg), and selenium (Se). We found dramatic increases in hepatic concentrations of Hg, Se, sum PCBs, p,p'-DDE, and other organochlorines in canvasbacks in which concentrations in February were greater than concentrations in November when overwintering ducks arrived in the study area.

Spatially explicit network analysis reveals multi-species annual cycle movement patterns of sea ducks.

Conservation of long-distance migratory species poses unique challenges. Migratory connectivity, that is, the extent to which groupings of individuals at breeding sites are maintained in wintering areas, is frequently used to evaluate population structure and assess use of key habitat areas. However, for species with complex or variable annual cycle movements, this traditional bimodal framework of migratory connectivity may be overly simplistic.

Mallard resource selection trade-offs in a heterogeneous environment during autumn and winter.

Animals select resources to maximize fitness but associated costs and benefits are spatially and temporally variable. Differences in wetland management influence resource availability for ducks and mortality risk from duck hunting. The local distribution of the Mallard () is affected by this resource heterogeneity and variable risk from hunting.

Inorganic Contaminants, Nutrient Reserves and Molt Intensity in Autumn Migrant Red-Necked Grebes (Podiceps grisegena) at Georgian Bay.

Red-necked grebes (Podiceps grisegena) are piscivorous waterbirds that breed on freshwater lakes in northwestern Canada and stop-over at the Great Lakes during autumn migration to molt feathers and replenish lipid and protein reserves. The objectives of this study were to (1) describe concentrations of, and correlations among, inorganic contaminants in a sample of autumn migrant red-necked grebes from the Great Lakes, (2) compare concentrations of inorganic contaminants to those in autumn migrant common loons from Schummer et al. (Arch Environ Contam Toxicol 62:704, 2011a), (3) evaluate if the inorganic elements are negatively associated with lipid and protein reserves, and (4) determine if nutrient reserves and molt intensity were correlated.

Effects of dietary selenium on the health and survival of captive wintering lesser scaup.

Accumulation of selenium (Se) by lesser and greater scaup (Aythya affinis, A. marila) at staging and wintering areas could have contributed to the decline in their continental population. We exposed lesser scaup to background (0.

Hepatic concentrations of inorganic contaminants and their relationships with nutrient reserves in autumn-migrant common loons at Lake Erie.

Common loons (Gavia immer) are piscivorous, high-trophic level feeders that bioaccumulate inorganic contaminants at concentrations that can negatively impact their health and reproduction. Concentrations of inorganic contaminants, especially mercury (Hg), in blood, organs, and muscle have been quantified in common loons on breeding grounds, but these data are limited for migrating loons. We investigated sex- and age-related hepatic concentrations of inorganic contaminants in common loons (n = 53) that died from botulism and were salvaged at a Great Lakes staging area (i.

Elemental contaminants in livers of mute swans on lakes Erie and St. Clair.

Contaminant inputs to the lower Great Lakes (LGL) have decreased since the 1960s and 1970s, but elemental contaminants continue to enter the LGL watershed at levels that are potentially deleterious to migratory waterfowl. Mute swans (Cygnus olor) using the LGL primarily eat plants, are essentially nonmigratory, forage exclusively in aquatic systems, and have increased substantially in number in the last few decades. Therefore, mute swans are an ideal sentinel species for monitoring elemental contaminants available to herbivorous and omnivorous waterfowl that use the LGL.

Selenium accumulation in sea ducks wintering at Lake Ontario.

Numbers of wintering sea ducks, including buffleheads (Bucephala albeola; BUFF), common goldeneyes (Bucephala clangula; COGO), and long-tailed ducks (Clangula hyemalis; LTDU), increased substantially at Lake Ontario after Dreissenid mussels (Dreissena bugensis and D. polymorpha) colonized the Great Lakes. Invertebrates, including Dreissenid mussels, are major diving duck prey items that can transfer some trace elements, such as selenium (Se) to higher trophic levels.

Relationships between hepatic trace element concentrations, reproductive status, and body condition of female greater scaup.

We collected female greater scaup (Aythya marila) on the Yukon-Kuskokwim Delta, Alaska during two breeding seasons to determine if concentrations of 18 trace elements in livers and eggs were elevated and if hepatic concentrations correlated with body condition or affected reproductive status. Fifty-six percent, 5%, and 42% of females, respectively, had elevated hepatic cadmium (Cd: >3 microg g(-1) dry weight [dw]), mercury (Hg: >3 microg g(-1) dw), and selenium (Se: >10 microg g(-1) dw). Somatic protein and lipid reserves were not correlated with hepatic Cd or Hg, but there was a weak negative correlation between protein and Se.