44 research outputs found
Resource partitioning and repeatability in foraging behaviours among four auks nesting in sympatry in a sub-Arctic ecosystem
No full textCHAPTER 2: Abstract.
Auks, a group of diving seabirds, share ecological similarities, and are often found in sympatrically-nesting assemblages at suitable nesting sites. Despite these similarities, it is expected that co-existing species have evolved strategies that reduce niche overlap in response to resource competition. The presence of Atlantic puffins (Fratercula arctica), razorbills (Alca torda), thick-billed (Uria lomvia) and common murres (Uria aalge) at the Gannet Islands, Labrador, is an opportunity to study interspecific interactions among the four main and similar species of a seabird assemblage. I compared the foraging
movement of adult birds, and chick and adult diet inferred from stable isotopes, as dimensions in the foraging niche among
these four auks. My results revealed that puffins and thick-billed murres headed offshore to forage, while razorbills and common murres were more coastal heading towards mainland Labrador. The patterns of spatial segregation found among
the coastal and the pelagic birds were mirrored by their stable isotope ratios, with a group of species foraging on a higher trophic level of an inshore food web, and the other foraging on a lower trophic level of an offshore and pelagic food web. The 'pelagic' species segregated on prey choice for the chick while differential alternate prey selection was the source of segregation between the 'coastal' species. My 17 findings are more evidence that segregation, in at least one or more dimensions of the foraging niche, is a key mechanism that potentially reduces interspecific competition among co-existing and closely related seabirds, explaining the persistence of such seabird assemblages through time.
Chapter 3: Abstract. In animal populations, there are individuals that are highly consistent while others are highly flexible in their behavioural strategy. Since seabirds forage in an environment regulated by bottom-up mechanisms, their foraging behaviour is expected to be more plastic in response to changing environmental conditions that might affect the distribution of their preferred prey. I was interested in looking at how short-term individual consistency in different foraging behaviours varies across species of an important seabird assemblage nesting in sympatry: Atlantic puffins (Fratercula arctica), razorbills (Alca torda), common murres (Uria aalge) and thick-billed murres (Uria lomvia). I looked at the repeatability in foraging effort (maximum distance and duration) as well as in foraging locations of individual foraging trips to assess the various levels of individual consistency for those given behaviours. Observed individual repeatability for all
behaviours varied considerably by species. Puffins proved to be highly flexible, contrasting with razorbills that were highly consistent, while a range of individual consistencies were revealed in thick-billed murres and to a lesser extent in common
murres. These interspecific differences were likely promoted by differences in specific optimal prey availability and perhaps were reflecting individual strategies such as specialization for particular prey items. Because there is a need to better understand 57 individual foraging decisions and how consistency in behaviour influences or is influenced by an individual's intrinsic characteristics, I related individual consistency with individual physiological and body condition in thick-billed murres. I found strong correlations both positive and negative between individual-level repeatability indices and individual intrinsic components suggesting that individual consistency in foraging effort and flexibility in foraging location are intrinsically linked to individual capacities and constraints
Nest usurpation by a common eider toward a long-tailed duck
No full textIntraspecific and non-obligate brood parasitism and nest takeover is well documented in common eiders (Somateria mollissima borealis) nesting in the Arctic. However, we report the takeover of a long-tailed duck (Clangula hyemalis) nest by a female common eider on Nasaruvaalik Island, Nunavut, Canada. The high nesting density due to limited habitat in the region may have contributed to this seemingly risky behaviour, which provides no clear benefits to the eider
Le prêt de consommation : contrat réel ou consensuel?
No full textCet article examine la nature juridique du contrat de consommation. Dans un premier temps, l’auteure démontre l’importance de s’attarder à cette qualification. Dans un deuxième temps, elle analyse et critique la position traditionnelle qualifiant le prêt de consommation de contrat réel et démontre les raisons qui militent en faveur du caractère consensuel de ce contrat.This article examines the juridical nature of the contract of loan for consumption. Firstly, the author points out why such a determination is so important. The second part of the article is devoted to a critical analysis of the traditional view which holds that loan for consumption is a real contract. The author argues that this contract should be treated as one which is consensual in nature
PLI_iso_Dryad
No full textIsotopic data (d13C, d15N) in eggs corrected for lipid concentration (d13C) of four seabird species breeding at Prince Leopold Island, Nunavut. (two outliers have been removed
Passive acoustic monitoring of birds facing climate change in the Canadian Arctic
No full textInternational audienceOur project aims to monitor the long-term effects of climate change on Arctic Canadian birds using passive acoustics. The first year of monitoring begins in 2025, with 12 stations and 25 sensors deployed over more than 3,000 km, from the subarctic to the high Arctic. Recordings, made every morning and over three full days, allow researchers to analyze bird community composition, arrival dates, and activity rhythms. Early results show that with increasing latitude, bird communities become poorer, arrival dates shift by several weeks, and circadian activity rhythms gradually disappear at the highest latitudes of Nunavik
Projet "LATITUDE".: Suivi par acoustique passive des oiseaux face aux changements climatiques dans l'Arctique canadien.
No full textNational audienceClimate change and its effects on biodiversity are very marked in the Arctic, where long-term monitoring of wildlife is imperative. Aware of the logistical, financial and ethical challenges associated with field missions in these regions, our approach is based on the use of innovative passive acoustic monitoring methods. This project, in close collaboration between French researchers in ecology (CNRS Ecologie & Environnement) and acoustic signal processing (CNRS Sciences informatiques), in partnership with Canadian colleagues specializing in polar ecology (Centre d'Etudes Nordiques, UQAR, Moncton University) and Nunavik's national parks, aims to address the impacts of climate change while tackling several major interdisciplinary challenges. Through a pilot project funded by LabEx DRIIHM and OHMI-Nunavik in 2022-2023, we have demonstrated the feasibility of automated monitoring using sensors deployed at 3 stations.This project aims to deploy this network at 12 stations along a 3000 km latitudinal gradient from the subarctic to the high arctic. This approach, which minimizes costs, travel and disturbance, must answer 4 questions:(1) What are the reassemblies of bird communities?(2) What are the changes in bird arrival dates at breeding sites?(3) Is there a change in the singing phenology and(4) circadian rhythms of bird vocal activity over the long term?The interdisciplinary nature of our project is reflected in the close collaboration between experts in ecology, computer science and polar science. This approach relies on technological advances in automated sound processing, aimed at providing robust ecological results and data accessibility to a wide audience.Le changement climatique et ses effets sur la biodiversité sont très marqués dans l’Arctique où des suivis à long-terme de la faune sont impératifs. Conscients des défis logistiques, financiers, et éthiques liés aux missions de terrain dans ces régions, notre approche repose sur l’utilisation de méthodes de suivi acoustique passif innovantes. Ce projet, en collaboration étroite entre des chercheurs français en écologie (CNRS Ecologie & Environnement) et en traitement du signal acoustique (CNRS Sciences informatiques), en partenariat avec des collègues canadiens spécialisés en écologie polaire (Centre d’Etudes Nordiques, UQAR, Moncton University) et les parcs nationaux du Nunavik, vise à aborder les impacts du changement climatique tout en relevant plusieurs défis interdisciplinaires majeurs. À travers un projet pilote financé par le LabEx DRIIHM et l’OHMI-Nunavik en 2022-2023, nous avons montré la faisabilité d’un suivi automatisé à l’aide de capteurs déployés dans 3 stations.Ce projet vise à déployer ce réseau sur 12 stations le long d’un gradient latitudinal de 3000 km du subarctique au haut-arctique. Cette approche, qui minimise les coûts, les déplacements et les dérangements, doit répondre à 4 questions :(1) Quels sont les réassemblages de communautés d’oiseaux ?(2) Quels sont les changements de dates d’arrivées des oiseaux sur les sites de nidification ?(3) Y a-t-il un changement de la phénologie de chant et(4) des rythmes circadiens d’activité vocale des oiseaux sur le long terme ?Le caractère interdisciplinaire de notre projet se manifeste par la collaboration étroite entre des experts en écologie, en informatique et en sciences polaires. Cette approche repose sur des avancées technologiques en traitement automatisé des sons, visant à fournir des résultats écologiques robustes et une accessibilité aux données auprès d’un large public
Projet "LATITUDE".: Suivi par acoustique passive des oiseaux face aux changements climatiques dans l'Arctique canadien.
No full textNational audienceClimate change and its effects on biodiversity are very marked in the Arctic, where long-term monitoring of wildlife is imperative. Aware of the logistical, financial and ethical challenges associated with field missions in these regions, our approach is based on the use of innovative passive acoustic monitoring methods. This project, in close collaboration between French researchers in ecology (CNRS Ecologie & Environnement) and acoustic signal processing (CNRS Sciences informatiques), in partnership with Canadian colleagues specializing in polar ecology (Centre d'Etudes Nordiques, UQAR, Moncton University) and Nunavik's national parks, aims to address the impacts of climate change while tackling several major interdisciplinary challenges. Through a pilot project funded by LabEx DRIIHM and OHMI-Nunavik in 2022-2023, we have demonstrated the feasibility of automated monitoring using sensors deployed at 3 stations.This project aims to deploy this network at 12 stations along a 3000 km latitudinal gradient from the subarctic to the high arctic. This approach, which minimizes costs, travel and disturbance, must answer 4 questions:(1) What are the reassemblies of bird communities?(2) What are the changes in bird arrival dates at breeding sites?(3) Is there a change in the singing phenology and(4) circadian rhythms of bird vocal activity over the long term?The interdisciplinary nature of our project is reflected in the close collaboration between experts in ecology, computer science and polar science. This approach relies on technological advances in automated sound processing, aimed at providing robust ecological results and data accessibility to a wide audience.Le changement climatique et ses effets sur la biodiversité sont très marqués dans l’Arctique où des suivis à long-terme de la faune sont impératifs. Conscients des défis logistiques, financiers, et éthiques liés aux missions de terrain dans ces régions, notre approche repose sur l’utilisation de méthodes de suivi acoustique passif innovantes. Ce projet, en collaboration étroite entre des chercheurs français en écologie (CNRS Ecologie & Environnement) et en traitement du signal acoustique (CNRS Sciences informatiques), en partenariat avec des collègues canadiens spécialisés en écologie polaire (Centre d’Etudes Nordiques, UQAR, Moncton University) et les parcs nationaux du Nunavik, vise à aborder les impacts du changement climatique tout en relevant plusieurs défis interdisciplinaires majeurs. À travers un projet pilote financé par le LabEx DRIIHM et l’OHMI-Nunavik en 2022-2023, nous avons montré la faisabilité d’un suivi automatisé à l’aide de capteurs déployés dans 3 stations.Ce projet vise à déployer ce réseau sur 12 stations le long d’un gradient latitudinal de 3000 km du subarctique au haut-arctique. Cette approche, qui minimise les coûts, les déplacements et les dérangements, doit répondre à 4 questions :(1) Quels sont les réassemblages de communautés d’oiseaux ?(2) Quels sont les changements de dates d’arrivées des oiseaux sur les sites de nidification ?(3) Y a-t-il un changement de la phénologie de chant et(4) des rythmes circadiens d’activité vocale des oiseaux sur le long terme ?Le caractère interdisciplinaire de notre projet se manifeste par la collaboration étroite entre des experts en écologie, en informatique et en sciences polaires. Cette approche repose sur des avancées technologiques en traitement automatisé des sons, visant à fournir des résultats écologiques robustes et une accessibilité aux données auprès d’un large public
Attention to attributes and objects in working memory
No full textIt has been debated on the basis of change-detection procedures whether visual working memory is limited by the number of objects, task-relevant attributes within those objects, or bindings between attributes. This debate, however, has been hampered by several limitations, including the use of conditions that vary between studies and the absence of appropriate mathematical models to estimate the number of items in working memory in different stimulus conditions. We reexamined working memory limits in 2 experiments with a wide array of conditions involving color and shape attributes, relying on a set of new models to fit various stimulus situations. In Experiment 2, a new procedure allowed identical retrieval conditions across different conditions of attention at encoding. The results show that multiple attributes compete for attention, but that retaining the binding between attributes is accomplished only by retaining the attributes themselves. We propose a theoretical account in which a fixed object capacity limit contains within it the possibility of the incomplete retention of object attributes, depending on the direction of attention.</p
Le prêt de consommation : contrat réel ou consensuel?
No full textCet article examine la nature juridique du contrat de consommation.
Dans un premier temps, I'auteure démontre l'importance de
s'attarder à cette qualification. Dans un deuxième temps, elle
analyse et critique la position traditionnelle qualifiant le prêt de
consommation de contrat réel et démontre les raisons qui militent en
faveur du caractère consensuel de ce contrat.Abstract: This article examines the juridical nature of the contract of
loan for consumption. Firstly, the author points out why such a
determination is so important. The second part of the article is
devoted to a critical analysis of the traditional view which holds
that loan for consumption is a real contract. The author argues
that this contract should be treated as one which is consensual in
nature
Projet "LATITUDE".: Suivi par acoustique passive des oiseaux face aux changements climatiques dans l'Arctique canadien.
No full textNational audienceClimate change and its effects on biodiversity are very marked in the Arctic, where long-term monitoring of wildlife is imperative. Aware of the logistical, financial and ethical challenges associated with field missions in these regions, our approach is based on the use of innovative passive acoustic monitoring methods. This project, in close collaboration between French researchers in ecology (CNRS Ecologie & Environnement) and acoustic signal processing (CNRS Sciences informatiques), in partnership with Canadian colleagues specializing in polar ecology (Centre d'Etudes Nordiques, UQAR, Moncton University) and Nunavik's national parks, aims to address the impacts of climate change while tackling several major interdisciplinary challenges. Through a pilot project funded by LabEx DRIIHM and OHMI-Nunavik in 2022-2023, we have demonstrated the feasibility of automated monitoring using sensors deployed at 3 stations.This project aims to deploy this network at 12 stations along a 3000 km latitudinal gradient from the subarctic to the high arctic. This approach, which minimizes costs, travel and disturbance, must answer 4 questions:(1) What are the reassemblies of bird communities?(2) What are the changes in bird arrival dates at breeding sites?(3) Is there a change in the singing phenology and(4) circadian rhythms of bird vocal activity over the long term?The interdisciplinary nature of our project is reflected in the close collaboration between experts in ecology, computer science and polar science. This approach relies on technological advances in automated sound processing, aimed at providing robust ecological results and data accessibility to a wide audience.Le changement climatique et ses effets sur la biodiversité sont très marqués dans l’Arctique où des suivis à long-terme de la faune sont impératifs. Conscients des défis logistiques, financiers, et éthiques liés aux missions de terrain dans ces régions, notre approche repose sur l’utilisation de méthodes de suivi acoustique passif innovantes. Ce projet, en collaboration étroite entre des chercheurs français en écologie (CNRS Ecologie & Environnement) et en traitement du signal acoustique (CNRS Sciences informatiques), en partenariat avec des collègues canadiens spécialisés en écologie polaire (Centre d’Etudes Nordiques, UQAR, Moncton University) et les parcs nationaux du Nunavik, vise à aborder les impacts du changement climatique tout en relevant plusieurs défis interdisciplinaires majeurs. À travers un projet pilote financé par le LabEx DRIIHM et l’OHMI-Nunavik en 2022-2023, nous avons montré la faisabilité d’un suivi automatisé à l’aide de capteurs déployés dans 3 stations.Ce projet vise à déployer ce réseau sur 12 stations le long d’un gradient latitudinal de 3000 km du subarctique au haut-arctique. Cette approche, qui minimise les coûts, les déplacements et les dérangements, doit répondre à 4 questions :(1) Quels sont les réassemblages de communautés d’oiseaux ?(2) Quels sont les changements de dates d’arrivées des oiseaux sur les sites de nidification ?(3) Y a-t-il un changement de la phénologie de chant et(4) des rythmes circadiens d’activité vocale des oiseaux sur le long terme ?Le caractère interdisciplinaire de notre projet se manifeste par la collaboration étroite entre des experts en écologie, en informatique et en sciences polaires. Cette approche repose sur des avancées technologiques en traitement automatisé des sons, visant à fournir des résultats écologiques robustes et une accessibilité aux données auprès d’un large public
