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mortality of common loons in new england, 1987 to 2000.diagnostic findings are presented on 522 common loons (gavia immer) found dead or moribund in new england (connecticut, maine, massachusetts, new hampshire, rhode island, and vermont, usa) between 1987 and 2000. common loon numbers and range in new england have decreased from historic levels over the last century due to a number of proposed factors. goals of this study were to identify and categorize causes of mortality and quantify natural versus anthropogenic causes. the majority of identifiab ...200312910757
an outbreak of type e botulism among common loons (gavia immer) in michigan's upper peninsula.an epizootic of type e botulism (clostridium botulinum) occurred among common loons (gavia immer) along the lake michigan shore of michigan's upper peninsula (usa) during october and november 1983. an estimated 592 dead loons washed ashore along the garden peninsula. type e botulinal toxin was demonstrated in blood samples and stomach contents of dead loons, and in samples of three species of dead fish found on the lake michigan shore. we suspect that loons acquired botulism by ingesting sick or ...19883411704
salmonella and aspergillus infections in common loons overwintering in florida.during a 5-year period (1970-1975), 190 common loons (gavia immer) from overwintering populations on the east and west coasts of florida were examined for evidence of infectious diseases. salmonella spp (representing 8 serotypes) were isolated from 27 (14%) of the loons, and lesions typical of those produced by aspergillus fumigatus were found in 34 (18%) of the loons. seven loons were infected with salmonella spp and had lesions typical of aspergillus infection. the largest number of loons (124 ...1976789314
spatial patterns of mercury in biota of adirondack, new york lakes.we studied the spatial distribution patterns of mercury (hg) in lake water, littoral sediments, zooplankton, crayfish, fish, and common loons in 44 lakes of the adirondacks of new york state, usa, a region that has been characterized as a "biological hg hotspot". our study confirmed this pattern, finding that a substantial fraction of the lakes studied had fish and loon samples exceeding established criteria for human and wildlife health. factors accounting for the spatial variability of hg in l ...201121691858
antimicrobial resistant salmonella spp. isolated from double-crested cormorants (phalacrocorax auritus) and common loons (gavia immer) in florida.antimicrobial resistant salmonella spp. were found in double-crested cormorants and common loons in florida. single or multiple resistance occurred in all salmonella agona isolates from cormorants, primarily to ampicillin, sulfonamids, streptomycin, neomycin, and kanamycin. similar patterns of resistance were found in s. agona isolates from common loons. in addition, isolates of s. saint paul from loons were found resistant to tetracycline and streptomycin, while 2 of 7 isolates of s. infantis w ...1979384026
brevetoxicosis in seabirds naturally exposed to karenia brevis blooms along the central west coast of florida.harmful algal bloom events caused by the dinoflagellate karenia brevis occurred along the central west florida, usa, coast from february 2005 through december 2005 and from august 2006 through december 2006. during these events, from 4 february 2005 through 28 november 2006, live, debilitated seabirds admitted for rehabilitation showed clinical signs that included disorientation, inability to stand, ataxia, and seizures. testing of blood, biologic fluids, and tissues for brevetoxin by enzyme-lin ...201323568900
renal coccidiosis caused by eimeria gaviae n. sp. in a common loon (gavia immer).renal coccidiosis was diagnosed in a common loon (gavia immer). this is the first report of coccidium from the kidney of a member of the order gaviiformes. morphologically, the coccidium was considered to be an eimeria sp. distinct from eimeria truncata, and was named eimeria gaviae n. sp.1978749899
polycyclic aromatic hydrocarbons in blood related to lower body mass in common loons.we captured 93 wintering adult and subadult common loons (gavia immer) in coastal louisiana from 2011 to 2015 following the deepwater horizon oil spill. we tested blood samples for exposure to polycyclic aromatic hydrocarbons (pahs) and measured physiological variables including hematocrit, hemoglobin and total blood protein. pah concentrations in loon blood differed from year to year and by age class. high pah concentrations were significantly related to lower body masses in both adult and suba ...201627177142
mercury, selenium and neurochemical biomarkers in different brain regions of migrating common loons from lake erie, canada.common loons (gavia immer) can be exposed to relatively high levels of dietary methylmercury (mehg) through fish consumption, and several studies have documented mehg-associated health effects in this species. to further study the neurological risks of mehg accumulation, migrating loons dying of type e botulism were collected opportunistically from the lake erie shore at long point (ontario, canada) and relationships between total mercury (thg), selenium (se), and selected neurochemical receptor ...201121847660
derivation of screening benchmarks for dietary methylmercury exposure for the common loon (gavia immer): rationale for use in ecological risk assessment.the current understanding of methylmercury (mehg) toxicity to avian species has improved considerably in recent years and indicates that exposure to environmentally relevant concentrations of mehg through the diet can adversely affect various aspects of avian health, reproduction, and survival. because fish-eating birds are at particular risk for elevated mehg exposure, the authors surveyed the available primary and secondary literature to summarize the effects of dietary mehg on the common loon ...201222865698
impacts of acid rainon aquatic birds.studies of toxicological and ecological effects of acidification on aquatic birds in europe and north america are reviewed. heavy metals are deposited by acid emissions, which also increase solubility and mobility of heavy metals in soil and water. aluminium is leached from soil and mobilized from lake sediments under acid conditions; it removes susceptible fish and invertebrate species and contaminates remaining invertebrates. it is not highly toxic to birds, but may interfere with their regula ...198924249190
general and histological indicators of health in wild fishes from a biological mercury hotspot in northeastern north america.kejimkujik national park and national historic site, nova scotia, canada, is considered a biological mercury (hg) hotspot because the tissues of yellow perch (perca flavescens) and common loons (gavia immer) inhabiting the lakes frequently exceed so-called safe levels of hg. in the present study, the relationships between hg and overall health of males and females of 3 forage fish species (brown bullhead ameirus nebulosus, banded killifish fundulus diaphanus, and golden shiner notemigonus crysol ...201727595668
toxicological significance of mercury in yellow perch in the laurentian great lakes region.we assessed the risks of mercury in yellow perch, a species important in the trophic transfer of methylmercury, in the great lakes region. mean concentrations in whole perch from 45 (6.5%) of 691 waters equaled or exceeded 0.20 μg/g w.w., a threshold for adverse effects in fish. in whole perch within the size range eaten by common loons (<100 g), mean concentrations exceeded a dietary threshold (0.16 μg/g w.w.) for significant reproductive effects on loons in 19 (7.3%) of 260 waters. mean concen ...201122024153
detection and phylogenetic characterization of a novel herpesvirus from the trachea of two stranded common loons (gavia immer).two wild adult common loons (gavia immer) were evaluated after being found stranded in mainland north-central florida on separate occasions. on the basis of upper airway endoscopic and cytologic findings, we diagnosed severe ulcerative tracheitis antemortem in one of the birds while more subtle lesions were observed in the other. a novel herpesvirus was detected in antemortem tracheal samples using nested consensus pcr amplification of the polymerase gene and sequencing. despite prolonged intens ...201121270015
Selenium accumulation and reproduction in birds breeding downstream of a uranium mill in northern Saskatchewan, Canada.Selenium (Se) concentrations in aquatic invertebrates and bird eggs collected along the treated effluent receiving environment of the Key Lake uranium mill in northern Saskatchewan were significantly greater than from nearby reference areas, and in some cases (e.g., eggs of common loons-Gavia immer) were higher than commonly used thresholds for adverse reproductive effects in birds (i.e., 5 µg/g dry weight in diet; 12-15 µg/g dry weight in eggs). Mean Se concentrations in tree swallow (Tachycine ...201121927945
digestive physiology: a view from molecules to ecosystem.digestive physiology links physiology to applications valued by society, such as understanding ecology and ecological toxicology and managing and conserving species. here i illustrate this applied and integrative perspective with several avian case studies. the match between digestive features and diet provides evidence of tradeoffs that preclude doing well on all possible substrates with a single digestive design, and this influences ecological niche partitioning. but some birds, such as wild h ...201121653878
mercury and other contaminants in common loons breeding in atlantic canada.common loons (gavia immer) were studied to assess the biomagnification of persistent contaminants in lake ecosystems in atlantic canada. forty-two breeding adults and 20 juvenile loons were captured in august, 1995-1997 on lakes in four areas of southern new brunswick (lepreau and fundy national park) and nova scotia (halifax and kejimkujik national park). blood samples were collected for analysis of mercury, methylmercury, lead, and selenium. plasma samples from adult loons were analyzed for pc ...200515931969
interactive mortality factors in common loons from maritime canada.between august 1992 and november 1995, 31 moribund or dead common loons (gavia immer) found in the three maritime provinces of canada (new brunswick, nova scotia, prince edward island) were necropsied. eight of these birds were in good body condition and died acutely from drowning or trauma. the remaining 23 birds were in poor body condition and had either chronic lead poisoning, respiratory mycosis, or oil contamination of their plumage. loons in poor body condition had significantly higher num ...19989706561
mercury and other element exposure in tree swallows nesting at low ph and neutral ph lakes in northern wisconsin usa.the primary objective of this study was to determine whether tree swallows (tachycineta bicolor) demonstrate similar responses to lake ph and mercury (hg) contamination in northern wisconsin as do common loons (gavia immer). similar to common loons, hg concentrations in the blood of tree swallow nestlings were higher, hg concentrations in eggs tended to be higher, and egg size tended to be smaller at low (<6.2) ph lakes. in contrast to common loons, tree swallow nestling production was not lower ...201222325433
prevalence of leucocytozoon spp, in the endangered yellow-eyed penguin megadyptes antipodes.yellow-eyed penguins on stewart island were identified with a leucocytozoon spp. of a novel lineage in association with a high regional incidence of chick mortality (n=32, 100% mortality) during the november 2006 to january 2007 breeding season. fourteen chicks from stewart island were examined post-mortem and histologically for leucocytozoon infection. in addition, a survey of blood to detect leucocytozoon spp. infections using pcr was performed on 107 yellow-eyed penguins from 4 distinct nesti ...201020557665
relating land cover characteristics and common loon mercury levels using geographic information systems.this effort models the relationship between mercury (hg) levels in the common loon (gavia immer) and land cover types as defined by the national land cover database (nlcd). we constructed the model within the framework of a gis to analyze the spatial relationships between land cover types and blood hg levels in male common loons. thiessan polygons were used to generate the territory for each loon. we created 150, 300, and 600-m buffers around the thiessan polygons and modeled the relationships t ...200515931970
adverse effects from environmental mercury loads on breeding common loons.anthropogenic inputs of mercury (hg) into the environment have significantly increased in the past century. concurrently, the availability of methylmercury (mehg) in aquatic systems has increased to levels posing risks to ecological and human health. we use the common loon (gavia immer) as an upper trophic level bioindicator of aquatic hg toxicity in freshwater lakes. multiple endpoints were selected to measure potential negative impacts from mehg body burdens on behavior, physiology, survival a ...200817909967
mercury in swamp sparrows (melospiza georgiana) from wetland habitats in wisconsin.wetlands play a major role in the export of methylmercury (mehg) to a watershed. the large contribution of wetlands to watersheds in northern wisconsin, coupled with the acidic environment of this area, makes these habitats especially vulnerable to mercury (hg) accumulation by biota. the purpose of this study was to compare hg accumulation between northern wisconsin wetlands and southern wisconsin wetlands using the swamp sparrow (melospiza georgiana) as a representative species. the swamp sparr ...201121755351
bioaccumulation patterns and temporal trends of mercury exposure in wisconsin common loons.a long term field study was initiated by the wisconsin department of natural resources in 1992 to elucidate patterns of common loon (gavia immer) mercury (hg) exposure. analysis of loon blood and feather samples collected from recaptured adult loons in wisconsin 1992-2000 found evidence of a decline in overall body burdens of mercury in common loons for this region. the interval between sampling individual loons spanned 2-8 years, a sufficient length of time to observe a change in tissue hg conc ...201312739859
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 ...201222042040
spatial gradients of methylmercury for breeding common loons in the laurentian great lakes region.much of the laurentian great lakes region is a mercury-sensitive landscape, in which atmospheric deposition and waterborne sources of mercury (hg) have led to high concentrations of bioavailable methylmercury (mehg) in predatory fish and piscivorous wildlife. efforts since the early 1990s have established the common loon (gavia immer) as the primary avian indicator for evaluating the exposure and effects of mehg in north america. a regional hg dataset was compiled from multiple loon tissue types ...201121858513
necropsy findings and environmental contaminants in common loons from new york.diagnostic and analytical findings are presented for 105 common loons (gavia immer) found dead or debilitated in new york (usa) from 1972-99. aspergillosis (23% of cases) and ingestion of lead fishing weights (21%) were the most common pathologies encountered. stranding on land, shooting, other trauma, gill nets, air sacculitis and peritonitis, and emaciation of uncertain etiology accounted for most of the remaining causes of disease or death. analysis for total mercury in the liver of 83 loons ...200111272494
bi-phasic trends in mercury concentrations in blood of wisconsin common loons during 1992-2010.we assessed the ecological risk of mercury (hg) in aquatic systems by monitoring common loon (gavia immer) population dynamics and blood hg concentrations. we report temporal trends in blood hg concentrations based on 334 samples collected from adults recaptured in subsequent years (resampled 2-9 times) and from 421 blood samples of chicks collected at lakes resampled 2-8 times 1992-2010. temporal trends were identified with generalized additive mixed effects models and mixed effects models to a ...201121809120
effects of injected methylmercury on the hatching of common loon (gavia immer) eggs.to determine the level of in ovo methylmercury (mehg) exposure that results in detrimental effects on fitness and survival of loon embryos and hatched chicks, we conducted a field study in which we injected eggs with various doses of mehg on day 4 of incubation. eggs were collected following about 23 days of natural incubation and artificially incubated to observe hatching. reduced embryo survival was evident in eggs injected at a rate of ≥1.3 μg hg/g wet-mass. when maternally deposited hg and i ...201121789674
increasing mercury in yellow perch at a hotspot in atlantic canada, kejimkujik national park.in the mid-1990s, yellow perch (perca flavescens) and common loons (gavia immer) from kejimkujik national park and national historic site (knpnhs), nova scotia, canada, had among the highest mercury (hg) concentrations across north america. in 2006 and 2007, we re-examined 16 lakes to determine whether there have been changes in hg in the loon's preferred prey, yellow perch. total hg concentrations were measured in up to nine perch in each of three size classes (5-10 cm, 10-15 cm, and 15-20 cm) ...201021062071
a rapid postmortem screening test for lead toxicosis in common loons (gavia immer) and bald eagles (haliaeetus leucocephalus).in live animals, lead poisoning can be diagnosed by analyzing blood samples. for postmortem testing, blood samples are not available and analysis of liver or kidney is often used for diagnosis. liver and kidney analysis is relatively expensive and results might not be quickly available. we examined an inexpensive, rapid method to screen animals for lead toxicosis postmortem by testing the mixture of body fluids (termed "tissue fluids") that pool in the body cavity at necropsy for lead. at necrop ...201323778630
effects of methylmercury exposure on the behavior of captive-reared common loon (gavia immer) chicks.behavioral effects resulting from exposure to dietary methylmercury (mehg) have been reported in studies of several wildlife species. however, quantifying the impact of contaminant exposure on wild populations is complicated by the confounding effects of other environmental stressors. we controlled confounding stressors in a laboratory study to quantify the level of dietary mehg exposure associated with negative effects on the fitness of captive-reared common loon (gavia immer) chicks. we evalua ...201020217222
effects of methylmercury exposure on glutathione metabolism, oxidative stress, and chromosomal damage in captive-reared common loon (gavia immer) chicks.we quantified the level of dietary mercury (hg), delivered as methylmercury chloride (ch3hgcl), associated with negative effects on organ and plasma biochemistries related to glutathione (gsh) metabolism and oxidative stress, and chromosomal damage in captive-reared common loon (gavia immer) chicks reared from hatch to 105 days. mercury-associated effects related to oxidative stress and altered glutathione metabolism occurred at 1.2 microg hg/g and 0.4 microg hg/g, an ecologically relevant dieta ...200818657888
nestsite selection by male loons leads to sex-biased site familiarity.1. the concept that animals benefit from gaining familiarity with physical spaces is widespread among ecologists and constitutes a theoretical pillar in studies of territory defence, philopatry and habitat selection. yet proximate causes and fitness benefits of site familiarity are poorly known. 2. we used data from marked common loons gavia immer breeding on 98 territories over 14 years to investigate the 'win-stay, lose-switch rule' for nestsite placement (if eggs hatch, reuse nestsite; if pre ...200817976165
relationships among mercury, selenium, and neurochemical parameters in common loons (gavia immer) and bald eagles (haliaeetus leucocephalus).fish-eating birds can be exposed to levels of dietary methylmercury (mehg) known or suspected to adversely affect normal behavior and reproduction, but little is known regarding hg's subtle effects on the avian brain. in the current study, we explored relationships among hg, se, and neurochemical receptors and enzymes in two fish-eating birds--common loons (gavia immer) and bald eagles (haliaeetus leucocephalus). in liver, both species demonstrated a wide range of total hg (thg) concentrations, ...200817899374
nest platforms increase aggressive behavior in common loons.artificial manipulations of habitat, such as those that incorporate adding nesting boxes or platforms for birds, often enhance the breeding success of threatened animals. however, such alterations are likely to have unintended behavioral and ecological effects that might negatively impact the target species or others in its community. we conducted a controlled study to investigate the effect of artificial nesting platforms on aggressive behavior and reproductive success of male common loons (gav ...200817898978
an approach to predict risks to wildlife populations from mercury and other stressors.ecological risk assessments for mercury (hg) require measured and modeled information on exposure and effects. while most of this special issue focuses on the former, i.e., distribution and fate of hg within aquatic food webs, this paper describes an approach to predict the effects of dietary methylmercury (ch3hg) on populations of piscivorous birds. to demonstrate this approach, the u.s. environmental protection agency's national health and environmental effects research laboratory (u.s. epa nh ...200515931973
spatial patterns of methylmercury risks to common loons and piscivorous fish in canada.deposition of inorganic mercury (hg) from the atmosphere remains the principle source of hg contamination for most aquatic ecosystems. inorganic hg is readily converted to toxic methylmercury (mehg) that bioaccumulates in aquatic food webs and may pose a risk to piscivorous fish and wildlife. we conducted a screening-level risk assessment to evaluate the extent of risk to top aquatic piscivores: the common loon (gavia immer), walleye (sander vitreus), and northern pike (esox lucius). risk quotie ...201324156245
assessment of white blood cell phagocytosis as an immunological indicator of methylmercury exposure in birds.white blood cell (wbc) phagocytosis was investigated as a potential immunological indicator of methylmercury (mehg) exposure in birds. the assay was first assessed using chicken wbcs dosed with mehg in vitro either in whole blood or as isolated cells and later using blood of wild common loons exposed in vivo to a range of dietary mehg and having a range of blood-hg concentrations. whole blood and isolated wbcs from captive chickens were exposed to a range of mehg concentrations for 3 h. after me ...200312712280
cues used by the black fly, simulium annulus, for attraction to the common loon (gavia immer).the parasitic relationship between a black fly, simulium annulus, and the common loon (gavia immer) has been considered one of the most exclusive relationships between any host species and a black fly species. to test the host specificity of this blood-feeding insect, we made a series of bird decoy presentations to black flies on loon-inhabited lakes in northern wisconsin, u.s.a. to examine the importance of chemical and visual cues for black fly detection of and attraction to hosts, we made dec ...201223181860
major correlates of mercury in small fish and common loons (gavia immer) across four large study areas in canada.we investigated mercury (hg) concentrations in small fish (mainly yellow perch, perca flavescens; ∼60% of fish collected) and in blood of common loons (gavia immer) that prey upon them during the breeding season on lakes in 4 large, widely separated study areas in canada (>13 lakes per study area; total number of lakes = 93). although surface sediments from lakes near a base metal smelter in flin flon, manitoba had the highest hg concentrations, perch and other small fish and blood of common loo ...201626803793
influence of in ovo mercury exposure, lake acidity, and other factors on common loon egg and chick quality in wisconsin.a field study was conducted in wisconsin (usa) to characterize in ovo mercury (hg) exposure in common loons (gavia immer). total hg mass fractions ranged from 0.17 µg/g to 1.23 µg/g wet weight in eggs collected from nests on lakes representing a wide range of ph (5.0-8.1) and were modeled as a function of maternal loon hg exposure and egg laying order. blood total hg mass fractions in a sample of loon chicks ranged from 0.84 µg/g to 3.86 µg/g wet weight at hatch. factors other than mercury expos ...201526096773
hand‐rearing, growth, and development of common loon (gavia immer) chicks.common loon chicks were reared in captivity in association with studies to evaluate the effects of radiotransmitter implants and to assess the ecological risk of dietary methylmercury. here we report on hatching and rearing methods used to successfully raise chicks to 105 days of age. we experienced a 91.5% hatch rate, and 89.6% of loon chicks survived to the end of the study at 105 days. baseline information on observed rates of fish consumption, behavioral development, and growth patterns are ...201424753001
can settlement in natal-like habitat explain maladaptive habitat selection?the study of habitat selection has long been influenced by the ideal free model, which maintains that young adults settle in habitat according to its inherent quality and the density of conspecifics within it. the model has gained support in recent years from the finding that conspecifics produce cues inadvertently that help prebreeders locate good habitat. yet abundant evidence shows that animals often fail to occupy habitats that ecologists have identified as those of highest quality, leading ...201323804619
hematologic and physiologic reference ranges for free-ranging adult and young common loons (gavia immer).wild common loons (gavia immer) were captured across much of their southern north american range. hematologic and physiologic data were collected to establish reference ranges for adults and chicks from four geographic areas: new england, canadian maritimes, south-central quebec, and the upper great lakes. mean body mass and blood-glucose levels of adult loons varied among geographic regions. chicks had lower pcv and total solids than adult loons, and also had faster heart rates and higher blood ...200517312755
patterns and interpretation of mercury exposure in freshwater avian communities in northeastern north america.a large data set of over 4,700 records of avian mercury (hg) levels in northeastern north america was compiled and evaluated. as hg emissions remain poorly regulated in the united states and canada, atmospheric deposition patterns and associated ecological responses continue to elicit interest by landscape managers, conservation biologists, policy makers, and the general public. how avian hg exposure is interpreted greatly influences decision-making practices. the geographic extent and size of t ...200515931967
mercury in fish from the pinchi lake region, british columbia, canada.water, surface sediments, and <40 cm rainbow trout (oncorhynchus mykiss) and northern pikeminnow (ptychocheilus oregonensis) were collected from pinchi lake, british columbia, and from several nearby reference lakes. hg concentrations in sediment samples from pinchi l. were highly elevated compared to sediments from reference lakes, especially in sites adjacent to and downstream of a former hg mine. in both fish species examined, hg concentration was positively related to age and/or fork length. ...200415234094
the oral bioavailability and toxicokinetics of methylmercury in common loon (gavia immer) chicks.we compared the toxicokinetics of methylmercury in captive common loon chicks during two time intervals to assess the impact of feather growth on the kinetics of mercury. we also determined the oral bioavailability of methylmercury during these trials to test for age-related changes. the blood concentration-time curves for individuals dosed during feather development (initiated 35 days post hatch) were best described by a one-compartment toxicokinetic model with an elimination half-life of 3 day ...200212443928
mercury and selenium concentrations in livers and eggs of common loons (gavia immer) from minnesota.mercury and selenium act as mutual antagonists in mature birds, but their toxicity is additive or synergistic in avian embryos and immature birds. twenty eggs and livers from 18 mature and 9 immature common loon carcasses found in minnesota were collected. livers and eggs were analyzed for mercury and selenium by atomic emission and atomic absorption spectroscopy. liver mercury concentrations were significantly higher in mature loons compared to those of immature loons and eggs. liver selenium c ...200211706370
territory acquisition in loons: the importance of take-over.we examined patterns of territory acquisition and reconnaissance in common loons, gavia immer, from northern wisconsin. among all territory acquisitions, 41.5% occurred through passive occupation of territories left vacant after the death or desertion of a previous resident, 17% constituted founding of new territories and the remaining 41.5% came about through take-over: either usurpation of defended territories or appropriation of territories before the seasonal return of previous owners. take- ...200010675261
winter mortality of common loons in florida coastal waters.diagnostic findings are presented for 434 common loons (gavia immer) found sick or dead on florida beaches from 1970 through 1994, primarily during the months of december to april. the most commonly recognized problem was an emaciation syndrome (66%), followed by oiling (18%), aspergillosis (7%), trauma (5%) and miscellaneous disease entities (1%). the cause-of-death for 3% of the birds was not determined. many of the carcasses examined (n = 173) were obtained during an epizootic which occurred ...19979391969
the ecotoxicology of lead shot and lead fishing weights.: lead shot ingestion is the primary source of elevated lead exposure and poisoning in waterfowl and most other bird species. for some species (e.g. common loons, gavia immer), lead sinker ingestion is a more frequent cause of lead poisoning. in freshwater environments where recreational angling activity and loon populations co-occur, lead poisoning from ingestion of small (<50 gram) lead sinkers or jigs accounts for 10-50% of recorded adult loon mortality, depending on the locations studied. le ...199624193869
heavy metal concentrations in feathers of common loons (gavia immer) in the northeastern united states and age differences in mercury levels.feathers serve as a useful, non-destructive approach for biomonitoring some aspects of environmental quality. birds can eliminate over 90% of their body burden of mercury by sequestration in growing feathers, and they molt their feathers at least annually. thus mercury concentrations should not vary in avian feathers as a function of age. we tested the null hypothesis that there are no age differences in the concentrations of mercury, lead, cadmium, selenium, copper, chromium and manganese in th ...199424213705
observations on pcbs and mercury in common loons (gavia immer) collected from southwestern lake michigan.the death of common loons (gavia immer) was associated with a small spill of bunker-c oil off the chicago shoreline of lake michigan. petroleum oil was not found on the feathers or in the lungs of the birds. botulinus toxins c and e were found in heart blood. because the carcasses were autolysed, botulism toxins could have been produced postmortem. an average of 97 micrograms pcbs (aroclor 1254 standard) and 2.2 micrograms dieldrin/g of body fat also were found. concentrations of heavy metals in ...19902112805
lead poisoning in common loons (gavia immer).two emaciated common loons (gavia immer) were believed to have died of lead poisoning when fragments of fishing lines and lead sinkers were discovered in their stomachs. later a third emaciated loon, which had only the remnants of fishing line in its stomach, was suspected of being a possible lead-poisoning victim when all other test results were negative. the liver lead levels in the first two loons were 20.6 ppm and 46.1 ppm (wet weight), and the level in the third was 38.52 ppm (wet weight). ...20137103895
splendidofilaria fallisensis (nematoda) in the common loon, gavia immer (brünnich). 19744832973
distribution and accumulation of mercury in tissues of captive-reared common loon (gavia immer) chicks.we determined the distribution and accumulation of hg in tissues of common loon (gavia immer) chicks maintained for up to 15 weeks on either a control diet with no added methylmercury chloride (mehgcl) or one containing either 0.4 or 1.2 microg hg (as mehgcl)/g wet-weight food. total hg and mehg tissue concentrations were strongly positively correlated (r2 > 0.95) with the amount of hg delivered to individual chicks throughout the course of the experiment. the pattern of differential hg concentr ...200717521154
bioenergetic and pharmacokinetic model for exposure of common loon (gavia immer) chicks to methylmercury.a bioenergetics model was used to predict food intake of common loon (gavia immer) chicks as a function of body mass during development, and a pharmacokinetics model, based on first-order kinetics in a single compartment, was used to predict blood hg level as a function of food intake rate, food hg content, body mass, and hg absorption and elimination. predictions were tested in captive growing chicks fed trout (salmo gairdneri) with average mehg concentrations of 0.02 (control), 0.4, and 1.2 mi ...200717447552
effects of methylmercury exposure on the immune function of juvenile common loons (gavia immer).we conducted a dose-response laboratory study to quantify the level of exposure to dietary hg, delivered as methylmercury chloride (ch3hgcl), that is associated with suppressed immune function in captive-reared common loon (gavia immer) chicks. we used the phytohemagglutinin (pha) skin test to assess t-lymphocyte function and the sheep red blood cell (srbc) hemagglutination test to measure antibody-mediated immunity. the pha stimulation index among chicks receiving dietary hg treatment did not d ...200717665687
are methylmercury concentrations in the wetlands of kejimkujik national park, nova scotia, canada, dependent on geology?in the relatively pristine ecosystem in kejimkujik park, nova scotia, methylmercury (mehg) concentrations in loons, gavia immer, are among the highest recorded anywhere in the world. this study investigated the influence of bedrock lithology on mehg concentrations in wetlands. twenty-five different wetland field sites were sampled over four different bedrock lithologies; kejimkujik monzogranite, black sulfidic slate, gray slate, and greywacke. soil samples were analyzed for ethylmercury (ethg), ...200314674530
mercury, methylmercury, and selenium concentrations in eggs of common loons (gavia immer) from canada.concentrations of hg and se were determined for a total of 125 common loon (gavia immer) eggs collected from lakes in alberta, saskatchewan, ontario, quebec, new brunswick and nova scotia, canada between 1972 and 1997. resulting data were compared to hg and/or se concentrations known or suspected to cause reproductive impairment in birds. organic (methyl) hg analyses were also performed on a subset of 24 loon eggs. thirty-nine of 125 eggs had total hg levels exceeding those (0.6 microg g(-1) ww, ...200111693555
effects of methyl mercury exposure on the growth of juvenile common loons.we conducted a dose-response laboratory study to quantify the level of mercury exposure associated with negative effects on the development of common loon chicks reared in captivity from hatch to 105 days. a dose regimen was implemented that provided exposure levels that bracketed relevant exposure levels of methyl mercury found in loon chicks across north america. we observed no overt signs of mercury toxicosis and detected no significant effect of dietary mercury exposure on growth or food con ...200612739866
common loon eggs as indicators of methylmercury availability in north america.increased anthropogenic mercury (hg) deposition since pre-industrial times, and subsequent transformation of inorganic hg to methylmercury (mehg) in aquatic environments, has created areas in north america where hg poses a relatively high risk to wildlife, especially long-lived, piscivorous species. from 1995 to 2001, we opportunistically collected 577 eggs abandoned by common loons from eight states. egg-hg concentrations ranged from 0.07 to 4.42 microg/g (ww) or 0.10 to 19.40 microg/g (dw). me ...200612739858
identification of long-chain perfluorinated acids in biota from the canadian arctic.recently it was discovered that humans and animals from various urban and remote global locations contained a novel class of persistent fluorinated contaminants, the most pervasive of which was perfluorooctane sulfonate (pfos). lower concentrations of perfluorooctanoate, perfluorohexane sulfonate, and heptadecafluorooctane sulfonamide have also been detected in various samples. although longer perfluoroalkyl carboxylates (pfcas) are used in industry and have been detected in fish following a spi ...200414750710
impacts of sublethal mercury exposure on birds: a detailed review.mercury is a ubiquitous environmental contaminant known to accumulate in, and negatively affect, fish-eating and oceanic bird species, and recently demonstrated to impact some terrestrial songbirds to a comparable extent. it can bioaccumulate to concentrations of >1 μg/g in tissues of prey organisms such as fish and insects. at high enough concentrations, exposure to mercury is lethal to birds. however, environmental exposures are usually far below the lethal concentrations established by dosing ...201728710647
documentation of malaria parasite ( plasmodium spp.) infection and associated mortality in a common loon (gavia immer).we report malaria parasite infection ( plasmodium spp.) and associated mortality in a common loon (gavia immer) found dead on lake umbagog in new hampshire, us. necropsy findings showed the bird to be in good body condition but with pericardial edema and splenomegaly. histopathological examination of brain and heart revealed intraendothelial and intrahistiocytic proliferation of plasmodium merozoites with myocarditis. by pcr, the presence of plasmodium parasites was confirmed from all tissues sc ...201728665230
mercury correlates with altered corticosterone but not testosterone or estradiol concentrations in common loons.we investigated the relation between environmental mercury exposure and corticosterone concentrations in free-living adult common loons (gavia immer). we determined blood and feather mercury concentrations and compared them to testosterone, estradiol, and stress-induced plasma corticosterone concentrations. although neither testosterone nor estradiol correlated with hg levels, there was a robust positive relation between blood hg and stress-induced corticosterone concentrations in males, but not ...201728437726
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 migran ...201526250452
merganser: an empirical model to predict fish and loon mercury in new england lakes.merganser (mercury geo-spatial assessments for the new england region) is an empirical least-squares multiple regression model using mercury (hg) deposition and readily obtainable lake and watershed features to predict fish (fillet) and common loon (blood) hg in new england lakes. we modeled lakes larger than 8 ha (4404 lakes), using 3470 fish (12 species) and 253 loon hg concentrations from 420 lakes. merganser predictor variables included hg deposition, watershed alkalinity, percent wetlands, ...201222372609
methylmercury exposure associated with reduced productivity in common loons.methylmercury can impair the reproduction of fish-eating wildlife. we measured lake ph, mercury (hg) concentrations in small fish, blood hg levels in adult male, female and juvenile common loons, and loon productivity from 120 lakes in wisconsin, usa and new brunswick and nova scotia, canada (maritimes). mean lake ph was higher in wisconsin than in the maritimes. body masses of adult loons and hg concentrations in the blood of loons and in small fish were greater in the maritimes. hg levels in f ...200818038272
residues of organochlorine insecticides, industrial chemicals, and mercury in eggs and in tissues taken from healthy and emaciated common loons, ontario, canada, 1968-1980. 19836651339
effects of environmental methylmercury on the health of wild birds, mammals, and fish.wild piscivorous fish, mammals, and birds may be at risk for elevated dietary methylmercury intake and toxicity. in controlled feeding studies, the consumption of diets that contained hg (as methylmercury) at environmentally realistic concentrations resulted in a range of toxic effects in fish, birds, and mammals, including behavioral, neurochemical, hormonal, and reproductive changes. limited field-based studies, especially with certain wild piscivorous bird species, e.g., the common loon, corr ...200717408187
assessing the recovery of lakes in southeastern canada from the effects of acidic deposition.reductions in north american sulfur dioxide (so2) emissions promoted expectations that aquatic ecosystems in southeastern canada would soon recover from acidification. only lakes located near smelters that have dramatically reduced emissions approach this expectation. lakes in the atlantic provinces, quebec and ontario affected only by long-range sources show a general decline in sulfate (so4(2-)) concentrations, but with a relatively smaller compensating increase in ph or alkalinity. several fa ...200312839192
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