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28 records – page 1 of 3.

Annual movement patterns of endangered ivory gulls: the importance of sea ice.

https://arctichealth.org/en/permalink/ahliterature259274
Source
PLoS One. 2014;9(12):e115231
Publication Type
Article
Date
2014
Author
Nora C Spencer
H Grant Gilchrist
Mark L Mallory
Source
PLoS One. 2014;9(12):e115231
Date
2014
Language
English
Publication Type
Article
Abstract
The ivory gull (Pagophila eburnea) is an endangered seabird that spends its entire year in the Arctic environment. In the past three decades, threats from various sources have contributed to a >70% decline in Canada. To assess the annual habitat needs of this species, we attached satellite transmitters to 12 ivory gulls on Seymour Island, Nunavut in 2010, which provided up to four breeding seasons of tracking data. Analysis of migratory behaviour revealed considerable individual variation of post-breeding migratory route selection. Ivory gulls traveled a median of 74 days during post-breeding migration, but only 18 days during pre-breeding migration. In contrast to predictions, ivory gulls did not use the Greenland coast during migratory periods. Ivory gulls overwintered near the ice edge in Davis Strait, but also used the Labrador Sea in late February and March. We suggest that the timing of formation and recession and extent of sea ice plays a large role in ivory gull distribution and migratory timing.
PubMed ID
25551556 View in PubMed
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Biomarker responses in nesting, common eiders in the Canadian arctic in relation to tissue cadmium, mercury and selenium concentrations.

https://arctichealth.org/en/permalink/ahliterature6027
Source
Ecotoxicology. 2003 Feb-Aug;12(1-4):225-37
Publication Type
Article
Author
Mark Wayland
Judit E G Smits
H Grant Gilchrist
Tracy Marchant
Jonathan Keating
Author Affiliation
Environment Canada, Prairie and Northern Region, Prairie and Northern Wildlife Research Centre, 115 Perimeter rd, Saskatoon, SK, Canada S7N 0X4. mark.wayland@ec.gc.ca
Source
Ecotoxicology. 2003 Feb-Aug;12(1-4):225-37
Language
English
Publication Type
Article
Keywords
Animals
Arctic Regions
Biological Markers - analysis
Body Burden
Cadmium - adverse effects - pharmacokinetics
Corticosterone - blood
Ducks
Female
Glycogen - analysis
Health status
Immune System - physiology
Liver - chemistry
Male
Mercury - adverse effects - pharmacokinetics
Population Dynamics
Research Support, Non-U.S. Gov't
Selenium - adverse effects - pharmacokinetics
Tissue Distribution
Vitamin A - analysis
Abstract
Populations of many North American sea ducks are declining. Biomarkers may offer valuable insights regarding the health and fitness of sea ducks in relation to contaminant burdens. In this study we examined body condition, immune function, corticosterone stress response, liver glycogen levels and vitamin A status in relation to tissue concentrations of mercury, selenium and cadmium in female common eiders during the nesting period. The study was conducted in the eastern Canadian arctic during July, 2000. Hepatic mercury, selenium and renal cadmium concentrations ranged 1.5-9.8, 6.5-47.5 and 74-389 microg/g, dry wt, respectively. Mercury concentrations were negatively related to dissection body mass, heart mass and fat mass. Cadmium concentrations were negatively related to mass at capture and dissection mass after controlling for the mercury concentration-dissection mass relationship. Cell-mediated immunity was assessed by the skin swelling reaction to an injection of phytohemagglutinin-P, and was unrelated to metal concentrations. After adjusting the corticosterone concentration to account for the time between capture and sampling, there was a negative relationship between the residual corticosterone concentration and selenium. Liver glycogen concentrations were not significantly related to metal concentrations. Mercury concentrations were positively related to those of hepatic retinol and retinyl palmitate and the ratio of the retinol to retinyl palmitate in liver. They were negatively related to the ratio of plasma to liver retinol. Our findings do not indicate that exposure to metals may have adversely affected the health of these birds. They do, however, suggest that more research is required to elucidate mechanisms by which exposure to these metals could impact body condition.
PubMed ID
12739870 View in PubMed
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Both short and long distance migrants use energy-minimizing migration strategies in North American herring gulls.

https://arctichealth.org/en/permalink/ahliterature305580
Source
Mov Ecol. 2020; 8:26
Publication Type
Journal Article
Date
2020
Author
Christine M Anderson
H Grant Gilchrist
Robert A Ronconi
Katherine R Shlepr
Daniel E Clark
David A Fifield
Gregory J Robertson
Mark L Mallory
Author Affiliation
Department of Biology, Acadia University, 33 Westwood Ave, Wolfville, NS B4P 2R6 Canada.
Source
Mov Ecol. 2020; 8:26
Date
2020
Language
English
Publication Type
Journal Article
Abstract
Recent studies have proposed that birds migrating short distances migrate at an overall slower pace, minimizing energy expenditure, while birds migrating long distances minimize time spent on migration to cope with seasonal changes in environmental conditions.
We evaluated variability in the migration strategies of Herring Gulls (Larus argentatus), a generalist species with flexible foraging and flight behaviour. We tracked one population of long distance migrants and three populations of short distance migrants, and compared the directness of their migration routes, their overall migration speed, their travel speed, and their use of stopovers.
Our research revealed that Herring Gulls breeding in the eastern Arctic migrate long distances to spend the winter in the Gulf of Mexico, traveling more than four times farther than gulls from Atlantic Canada during autumn migration. While all populations used indirect routes, the long distance migrants were the least direct. We found that regardless of the distance the population traveled, Herring Gulls migrated at a slower overall migration speed than predicted by Optimal Migration Theory, but the long distance migrants had higher speeds on travel days. While long distance migrants used more stopover days overall, relative to the distance travelled all four populations used a similar number of stopover days.
When taken in context with other studies, we expect that the migration strategies of flexible generalist species like Herring Gulls may be more influenced by habitat and food resources than migration distance.
PubMed ID
32549986 View in PubMed
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Changes in food web structure alter trends of mercury uptake at two seabird colonies in the canadian arctic.

https://arctichealth.org/en/permalink/ahliterature258239
Source
Environ Sci Technol. 2014 Nov 18;48(22):13246-52
Publication Type
Article
Date
Nov-18-2014
Author
Birgit M Braune
Anthony J Gaston
Keith A Hobson
H Grant Gilchrist
Mark L Mallory
Author Affiliation
Environment Canada, National Wildlife Research Centre, Carleton University , Raven Road, Ottawa, Ontario Canada K1A 0H3.
Source
Environ Sci Technol. 2014 Nov 18;48(22):13246-52
Date
Nov-18-2014
Language
English
Publication Type
Article
Abstract
Arctic ecosystems are changing in response to climate change and some Arctic food web structures are being affected in ways which may have potential consequences for the biomagnification of environmental contaminants. Here, we examined how a shift in diet of an Arctic seabird resulted in a change of trophic position and how that change affected exposure to mercury over time. The thick-billed murre (Uria lomvia), which breeds in the eastern Canadian Arctic, has been monitored for diet and environmental contaminants at two colonies, one in northern Hudson Bay and one in the high Arctic. As a result of a change in diet, murres breeding in Hudson Bay lowered their trophic position which, in turn, should affect their mercury exposure over time. After adjusting mercury concentrations in murre eggs for trophic position, the temporal trend of mercury in Hudson Bay murre eggs changed from nonsignificant to a significantly increasing trend. Valid trends can be deduced only when factors, such as diet, have been taken into account.
PubMed ID
25404000 View in PubMed
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Changes in trophic position affect rates of contaminant decline at two seabird colonies in the Canadian Arctic.

https://arctichealth.org/en/permalink/ahliterature260326
Source
Ecotoxicol Environ Saf. 2015 May;115:7-13
Publication Type
Article
Date
May-2015
Author
Birgit M Braune
Anthony J Gaston
Keith A Hobson
H. Grant Gilchrist
Mark L Mallory
Source
Ecotoxicol Environ Saf. 2015 May;115:7-13
Date
May-2015
Language
English
Publication Type
Article
Abstract
Some Arctic food web structures are being affected by climate change with potential consequences for long-term trends of environmental contaminants. We examined the effects of changes in trophic position of an Arctic-breeding seabird, the thick-billed murre (Uria lomvia), on declining rates of six major organochlorines (hexachlorobenzene, heptachlor epoxide, oxychlordane, dieldrin, p,p'-DDE and S69PCB) at two breeding colonies in the Canadian Arctic, one in northern Hudson Bay and one in the high Arctic. As a result of a change in diet, murres breeding in Hudson Bay lowered their trophic position during 1993-2013. After adjusting for the change in trophic position using egg d(15)N values, the rates of decline in concentrations of all six organochlorines were reduced in the Hudson Bay murre eggs. In contrast, the murres at the high Arctic colony experienced an increase in trophic position which resulted in an increase in the rates of decline for all adjusted concentrations, except for p,p'-DDE and S69PCB which remained relatively unchanged. This suggests that the dramatic reduction in emissions of these compounds during the 1970s/1980s had a greater influence on the time trends than changes in diet at the high Arctic colony. Linkages between climate change and food web processes are complex, and may have serious consequences for our understanding of contaminant temporal trends. Valid trends can be deduced only when these factors have been taken into account.
PubMed ID
25666731 View in PubMed
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Circumpolar dynamics of a marine top-predator track ocean warming rates.

https://arctichealth.org/en/permalink/ahliterature281658
Source
Glob Chang Biol. 2017 Apr 07;
Publication Type
Article
Date
Apr-07-2017
Author
Sébastien Descamps
Tycho Anker-Nilssen
Robert T Barrett
David B Irons
Flemming Merkel
Gregory J Robertson
Nigel G Yoccoz
Mark L Mallory
William A Montevecchi
David Boertmann
Yuri Artukhin
Signe Christensen-Dalsgaard
Kjell-Einar Erikstad
H Grant Gilchrist
Aili L Labansen
Svein-Håkon Lorentsen
Anders Mosbech
Bergur Olsen
Aevar Petersen
Jean-Francois Rail
Heather M Renner
Hallvard Strøm
Geir H Systad
Sabina I Wilhelm
Larisa Zelenskaya
Source
Glob Chang Biol. 2017 Apr 07;
Date
Apr-07-2017
Language
English
Publication Type
Article
Abstract
Global warming is a nonlinear process, and temperature may increase in a stepwise manner. Periods of abrupt warming can trigger persistent changes in the state of ecosystems, also called regime shifts. The responses of organisms to abrupt warming and associated regime shifts can be unlike responses to periods of slow or moderate change. Understanding of nonlinearity in the biological responses to climate warming is needed to assess the consequences of ongoing climate change. Here, we demonstrate that the population dynamics of a long-lived, wide-ranging marine predator are associated with changes in the rate of ocean warming. Data from 556 colonies of black-legged kittiwakes Rissa tridactyla distributed throughout its breeding range revealed that an abrupt warming of sea-surface temperature in the 1990s coincided with steep kittiwake population decline. Periods of moderate warming in sea temperatures did not seem to affect kittiwake dynamics. The rapid warming observed in the 1990s may have driven large-scale, circumpolar marine ecosystem shifts that strongly affected kittiwakes through bottom-up effects. Our study sheds light on the nonlinear response of a circumpolar seabird to large-scale changes in oceanographic conditions and indicates that marine top predators may be more sensitive to the rate of ocean warming rather than to warming itself.
PubMed ID
28387042 View in PubMed
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Energetic Physiology Mediates Individual Optimization of Breeding Phenology in a Migratory Arctic Seabird.

https://arctichealth.org/en/permalink/ahliterature276068
Source
Am Nat. 2016 Oct;188(4):434-45
Publication Type
Article
Date
Oct-2016
Author
Holly L Hennin
Jöel Bêty
Pierre Legagneux
H Grant Gilchrist
Tony D Williams
Oliver P Love
Source
Am Nat. 2016 Oct;188(4):434-45
Date
Oct-2016
Language
English
Publication Type
Article
Abstract
The influence of variation in individual state on key reproductive decisions impacting fitness is well appreciated in evolutionary ecology. Rowe et al. (1994) developed a condition-dependent individual optimization model predicting that three key factors impact the ability of migratory female birds to individually optimize breeding phenology to maximize fitness in seasonal environments: arrival condition, arrival date, and ability to gain in condition on the breeding grounds. While empirical studies have confirmed that greater arrival body mass and earlier arrival dates result in earlier laying, no study has assessed whether individual variation in energetic management of condition gain effects this key fitness-related decision. Using an 8-year data set from over 350 prebreeding female Arctic common eiders (Somateria mollissima), we tested this component of the model by examining whether individual variation in two physiological traits influencing energetic management (plasma triglycerides: physiological fattening rate; baseline corticosterone: energetic demand) predicted individual variation in breeding phenology after controlling for arrival date and body mass. As predicted by the optimization model, individuals with higher fattening rates and lower energetic demand had the earliest breeding phenology (shortest delays between arrival and laying; earliest laying dates). Our results are the first to empirically determine that individual flexibility in prebreeding energetic management influences key fitness-related reproductive decisions, suggesting that individuals have the capacity to optimally manage reproductive investment.
PubMed ID
27622877 View in PubMed
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Feather corticosterone reveals effect of moulting conditions in the autumn on subsequent reproductive output and survival in an Arctic migratory bird.

https://arctichealth.org/en/permalink/ahliterature259291
Source
Proc Biol Sci. 2015 Feb 7;282(1800)
Publication Type
Article
Date
Feb-7-2015
Author
N Jane Harms
Pierre Legagneux
H Grant Gilchrist
Joël Bêty
Oliver P Love
Mark R Forbes
Gary R Bortolotti
Catherine Soos
Source
Proc Biol Sci. 2015 Feb 7;282(1800)
Date
Feb-7-2015
Language
English
Publication Type
Article
Abstract
For birds, unpredictable environments during the energetically stressful times of moulting and breeding are expected to have negative fitness effects. Detecting those effects however, might be difficult if individuals modulate their physiology and/or behaviours in ways to minimize short-term fitness costs. Corticosterone in feathers (CORTf) is thought to provide information on total baseline and stress-induced CORT levels at moulting and is an integrated measure of hypothalamic-pituitary-adrenal activity during the time feathers are grown. We predicted that CORTf levels in northern common eider females would relate to subsequent body condition, reproductive success and survival, in a population of eiders nesting in the eastern Canadian Arctic during a capricious period marked by annual avian cholera outbreaks. We collected CORTf data from feathers grown during previous moult in autumn and data on phenology of subsequent reproduction and survival for 242 eider females over 5 years. Using path analyses, we detected a direct relationship between CORTf and arrival date and body condition the following year. CORTf also had negative indirect relationships with both eider reproductive success and survival of eiders during an avian cholera outbreak. This indirect effect was dramatic with a reduction of approximately 30% in subsequent survival of eiders during an avian cholera outbreak when mean CORTf increased by 1 standard deviation. This study highlights the importance of events or processes occurring during moult on subsequent expression of life-history traits and relation to individual fitness, and shows that information from non-destructive sampling of individuals can track carry-over effects across seasons.
PubMed ID
25540279 View in PubMed
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A geographical comparison of chlorinated, brominated and fluorinated compounds in seabirds breeding in the eastern Canadian Arctic.

https://arctichealth.org/en/permalink/ahliterature260233
Source
Environ Res. 2014 Oct;134:46-56
Publication Type
Article
Date
Oct-2014
Author
Birgit M Braune
Anthony J Gaston
Robert J Letcher
H. Grant Gilchrist
Mark L Mallory
Jennifer F Provencher
Source
Environ Res. 2014 Oct;134:46-56
Date
Oct-2014
Language
English
Publication Type
Article
Keywords
Animals
Arctic Regions
Birds - physiology
Breeding
Geography
Hydrocarbons, Brominated - analysis
Hydrocarbons, Chlorinated - analysis
Hydrocarbons, Fluorinated - analysis
Nunavut
Abstract
A suite of chlorinated, brominated and fluorinated organic contaminants were measured in livers of adult thick-billed murres (Uria lomvia) and northern fulmars (Fulmarus glacialis) from several locations in the eastern Canadian Arctic during 2007-2008. Thick-billed murres were collected from five colonies (Coats Island, Digges Island, Akpatok Island, Prince Leopold Island, Minarets) and northern fulmars from two colonies (Prince Leopold Island, Minarets). Legacy organochlorines (e.g. PCBs, DDT, chlorobenzenes, chlordanes) and perfluorooctane sulfonate (PFOS) dominated the compositional profiles of the measured halogenated compounds in the livers of both species at all colonies. Among the murre colonies sampled, Prince Leopold Island birds generally had the highest mean concentrations of organochlorines, whereas the highest mean concentration of sum (S) polybrominated diphenyl ethers (PBDEs) was found at the Minarets and the lowest at Prince Leopold Island. PBDEs were detected in only a few fulmar livers from the Minarets and in none of the fulmar livers from Prince Leopold Island. Mean PFOS concentrations were highest in both murre and fulmar livers at Prince Leopold Island. PFOS was approximately two orders of magnitude higher than the mean sum (S) perfluorinated carboxylate (PFCA) concentration in both species and at all colonies. The reasons for inter-colony and inter-species differences in contaminant liver levels are probably variable and complex, and likely reflect differences in contaminant transport and exposure pathways, as well as differences among colonies in their diets and overwintering areas. To our knowledge, this is the first spatial assessment of PBDEs, PFCAs and PFOS in seabirds from the Canadian Arctic.
PubMed ID
25046812 View in PubMed
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Helminths in common eiders (Somateria mollissima): Sex, age, and migration have differential effects on parasite loads.

https://arctichealth.org/en/permalink/ahliterature300863
Source
Int J Parasitol Parasites Wildl. 2019 Aug; 9:184-194
Publication Type
Journal Article
Date
Aug-2019
Author
Stine Vestbo
Claus Hindberg
Mark R Forbes
Mark L Mallory
Flemming Merkel
Rolanda J Steenweg
Peter Funch
H Grant Gilchrist
Gregory J Robertson
Jennifer F Provencher
Author Affiliation
Department of Bioscience, Aarhus University, Aarhus C, Denmark.
Source
Int J Parasitol Parasites Wildl. 2019 Aug; 9:184-194
Date
Aug-2019
Language
English
Publication Type
Journal Article
Abstract
In birds, parasites cause detrimental effects to the individual host, including reduced survival and reproductive output. The level of parasitic infection can vary with a range of factors, including migratory status, body size, sex, and age of hosts, or season. Understanding this baseline variation is important in order to identify the effects of external changes such as climate change on the parasitic load and potential impacts to individuals and populations. In this study, we compared the infection level (prevalence, intensity, and abundance) of gastrointestinal parasites in a total of 457 common eiders (Somateria mollissima) from four different sampling locations (Belcher Islands, Cape Dorset, West Greenland and Newfoundland), and explored the effects of migration, sex and age on levels of parasitism. Across all samples, eiders were infected with one nematode genus, two acanthocephalan genera, three genera of cestodes, and three trematode genera. Migratory phase and status alone did not explain the observed variation in infection levels; the expectation that post-migratory eiders would be more parasitized than pre-migratory eiders, due to the energetic cost of migration, did not fit our results. No effect of age was detected, whereas effects of sex and body size were only detected for certain parasitic taxa and was inconsistent with location. Since gastrointestinal helminths are trophically-transmitted, future studies of the regional and temporal variation in the diet of eiders and the associated variation and infestation level of intermediate hosts might further explain the observed variation of the parasitic load in eiders in different regions.
PubMed ID
31193602 View in PubMed
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28 records – page 1 of 3.