Comprendre la stratégie migratoire de trois espèces de grives du genre Catharus à l'aide d'un réseau innovateur de radio-télémétrie

Une meilleure connaissance des stratégies migratoires à l’échelle des espèces, des populations et des individus devrait faciliter l’identification de facteurs limitants et des défis rencontrés par les migrateurs. Les grives (Catharus spp.) de l’est de l’Amérique du nord semblent suivre le corridor de migration de l’Atlantique pour rejoindre leur aire d’hivernage plus au sud à l’automne. Jusqu’à récemment, les technologies ne nous permettaient pas de déterminer les différences entre les espèces, les populations et les individus à un niveau de résolution plus élevé. Cette étude compare les stratégies migratoires automnales individuelles de la Grive à dos olive, de la Grive de Bicknell et de la Grive à joues grises grâce à un réseau coordonné de radio-télémétrie, dont les récepteurs sont déployés dans l’est du Canada et des États-Unis. Les routes migratoires, la vitesse de migration et la variabilité interindividuelle ont été analysées. La Grive à dos olive migrait plus à l’ouest et utilisait davantage l’axe du Saint-Laurent et des Grands Lacs que la Grive de Bicknell et la Grive à joues grises, ces dernières longeant davantage la côte Atlantique. Les haltes migratoires utilisées par les trois espèces semblaient plus fréquentes au sud-est des États-Unis que plus au nord. Cependant, la progression vers le sud de la Grive à joues grises était plus rapide que celle des deux autres espèces. Les trois espèces avaient une variabilité individuelle importante (> 10 degrés) dans leur longitude maximale de migration. Dans une perspective de conservation, ces différences pourraient se traduire en enjeux différents entre les espèces, les populations et les régions. Les résultats de cette étude illustrent d’une nouvelle manière la polyvalence des stratégies migratoires chez des espèces aux caractéristiques écologiques similaires, et gagneront à être intégrés dans des efforts de synthèse visant une connaissance plus profonde des enjeux liés à la migration des oiseaux.A better knowledge of the migratory strategies at species, population and individual levels should facilitate the identification of limiting factors and challenges faced by migrants. Catharus thrushes from eastern North America appear to follow the Atlantic migration corridor to reach their wintering grounds further south in the fall. Until recently, technologies did not allow us to determine the differences between species, populations and individuals at a greater resolution. This study compares the individual fall migration strategies of the Swainson’s Thrush, the Bicknell's Thrush and the Gray-cheeked Thrush using a coordinated radio-telemetry network, which receiving stations are deployed in eastern Canada and the United States. Migration routes, migration paces, and individual variability were analyzed. The Swainson's Thrush migrated further west along the St. Lawrence River and the Great Lakes than Bicknell's Thrush and Gray-cheeked Thrush, which migrated along the Atlantic coast. Stopovers by the three species appeared more frequent on the southeastern United States than further North. However, Gray-cheeked Thrushes migrated faster than the other two species. Conspecifics exhibited significant individual variability (> 10 degrees) in maximum migration longitude. From a conservation perspective, these differences could translate into different stakes depending on species, populations and regions. The results of this study illustrate in a new way the versatility of migration strategies within species with similar ecological characteristic, and will benefit from being integrated into synthesis efforts aiming a deeper knowledge of the issues related to bird migration

Abatacept to induce remission of peanut allergy during oral immunotherapy (ATARI): protocol for a phase 2a randomized controlled trial

ContextWhile oral immunotherapy (OIT) has been shown to promote the remission of mild peanut allergy in young children, there is still an unmet need for a disease-modifying intervention for older patients and those with severe diseases. In mice models, abatacept, a cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) immunoglobulin fusion protein, has been shown to promote immune tolerance to food when used as an adjuvant to allergen immunotherapy. The goal of this study is to explore the potential efficacy of abatacept in promoting immune tolerance to food allergens during OIT in humans.MethodsIn this phase 2a proof-of-concept study (NCT04872218), 14 peanut-allergic participants aged from 14 to 55 years will be randomized at a 1:1 ratio to abatacept vs. placebo for the first 24 weeks of a peanut OIT treatment (target maintenance dose of 300 mg peanut protein). The primary outcome will be the suppression of the OIT-induced surge in peanut-specific IgE/total IgE at 24 weeks, relative to the baseline. Sustained unresponsiveness will be assessed as a secondary outcome starting at 36 weeks by observing incremental periods of peanut avoidance followed by oral food challenges.DiscussionThis is the first study assessing the use of abatacept as an adjuvant to allergen immunotherapy in humans. As observed in preclinical studies, the ability of abatacept to modulate the peanut-specific immune response during OIT will serve as a proxy outcome for the development of clinical tolerance, given the small sample size. The study will also test a new patient-oriented approach to sustained tolerance testing in randomized controlled trials

Insights on post-breeding movements from a northeastern population of Canada Warblers (Cardellina canadensis)

ABSTRACT : The study of migratory songbird transition periods, such as the post-breeding period, is complex because birds undertake different types of movements that vary in space and time. Nonetheless, it is important to understand the extent and duration of the territory and specific sites use to identify human activities likely to affect the species’ survival. Individuals from different regional populations may exhibit specific movements during the various phases of their annual cycle, and therefore conservation actions must be adapted. We studied a population of Canada Warblers (Cardellina canadensis) from the Saguenay region of Quebec, Canada, in the northeastern part of the species’ breeding range. We used a coordinated radio-telemetry network (Motus) to determine the residence time within the breeding territory, dates and times of departure, and early fall migration routes of 18 adult birds. We expected individuals to leave by mid-August and to migrate through the eastern flyway, along the Atlantic Coast. Six tracked individuals remained on their breeding territory until early September, corresponding to a residence time of approximately 90 days. These individuals left just after sunset on their day of departure. Twelve individuals departed earlier, and in the daytime, before the end of August; their earlier departure was likely for a purpose other than migration. Nine individuals were detected outside their breeding territory along the Atlantic migratory flyway: four migrated through the Great Lakes region, one in the Great Appalachian Valley, three along the Atlantic Coast or coastal plain, and one with an undetermined route. Our results suggest that adult Canada Warblers remain in the Saguenay region longer than expected, and that, although some individuals remain close to their breeding territory during the post-breeding period, others may use surrounding territories prior to initiating their fall migration. Our results will allow regional conservation managers to recommend that regional industry postpone the timing of certain activities that could negatively affect the species’ survival. Our study highlights the importance of fine-scale studies focused on specific periods of migratory songbird annual cycles to fill important knowledge gaps for understanding of the ecology of their species. RÉSUMÉ : L'étude des périodes de transition de passereaux migrateurs, comme la période post-nuptiale, est complexe car les oiseaux entreprennent différents types de déplacements qui varient dans l'espace et le temps. Néanmoins, il est important de comprendre l'étendue et la durée de l'utilisation du territoire et de sites spécifiques pour qu'on puisse déterminer quelles activités humaines sont susceptibles d'affecter la survie de l'espèce. Les individus de différentes populations régionales peuvent présenter des déplacements spécifiques au cours des diverses étapes de leur cycle annuel, et les activités de conservation doivent donc être adaptées. Nous avons étudié une population de Parulines du Canada (Cardellina canadensis) de la région du Saguenay au Québec, Canada, située dans la partie nord-est de l'aire de nidification de l'espèce. Nous avons utilisé un réseau coordonné de radiotélémétrie (Motus) pour déterminer le temps de résidence dans le territoire de nidification, les dates et les heures de départ, et les routes de migration au début de l'automne de 18 oiseaux adultes. Nous nous attendions à ce que les individus quittent à la mi-août et migrent par la voie de migration de l'est, le long de la côte atlantique. Six individus sont restés sur leur territoire de nidification jusqu'à début septembre, soit un temps de résidence d'environ 90 jours. Ces individus ont quitté juste après le coucher du soleil le jour de leur départ. Douze individus sont partis plus tôt, et de jour, avant la fin du mois d'août; leur départ précoce avait sans doute un but autre que la migration. Neuf individus ont été détectés en dehors de leur territoire de nidification le long de la voie de migration de l'Atlantique : quatre ont migré par la région des Grands Lacs, un dans la vallée des Appalaches, trois le long de la côte atlantique ou de la plaine côtière, et un dont nous n'avons pu déterminer l'itinéraire. Nos résultats indiquent que les Parulines du Canada adultes restent dans la région du Saguenay plus longtemps que prévu et que, bien que certains individus restent à proximité de leur territoire de nidification pendant la période postnuptiale, d'autres peuvent utiliser des territoires environnants avant d'entreprendre leur migration automnale. Nos résultats vont permettre aux gestionnaires de la conservation de recommander à l'industrie régionale de reporter le moment d'activités qui pourraient nuire à la survie de l'espèce. Nous soulignons l'importance de mener des études à l'échelle fine visant des périodes spécifiques du cycle annuel des passereaux migrateurs afin de combler les lacunes importantes dans la compréhension de l'écologie de ceux-ci

America Eats: Taste and Race in the New Deal Sensory Economy

Recent developments in sensory history highlight the rewards of a sensory approach to the topic of racial formation in twentieth century U.S. Yet, few explicitly focus on the sense of taste. This dissertation looks at sensory interaction over food as a site for the making of the interwar American racial landscape. The narrative focuses on the cornerstone period of the late 1930s-early 1940s and considers, through the notion of sensory economy, the extent to which the senses are part of modern circuits of economic and cultural exchanges. The argument builds on the Federal Writers’ Project (FWP) archive, especially the America Eats project; The FWP was one of the art programs of the New Deal Works Progress Administration (WPA) and an important part of the liberal state cultural apparatus. Considering the sense of taste as a cultural and economic currency circulating throughout the American social fabric as well as through the FWP archive allows highlighting taste as a medium for the negotiation of raced, gendered, ethnic, and regional identities in the interwar period. I examine how the FWP’s nostalgic and patriotic endeavour to record a national cuisine in the midst of the Great Depression contributed to the production and archiving of a prescriptive sensory and culinary knowledge about what was American food and who American eaters were. This dissertation documents how sensory interaction participated to the policing of the colour line but also to the creation of new tastes and, ultimately, to the birth of a commodified culinary plurality. The narrative also highlights how the encroachment of the food industries on American taste and the coming of World War II led to the upholding of conservative gender roles and stereotyped racial imagery. Finally, this dissertation examines the notion of region in the U.S. and looks at how the search for regional cuisines led FWP workers to use raced tastes as signals of regional authenticity. Overall, I suggest that a combined analysis of taste and race not only further our historical understanding of twentieth century American food culture but also enhances our comprehension of the role of the senses in race making.Ph

Comparing fall migration of three Catharus species using a radio-telemetry network

Migration routes vary greatly among small passerine species and populations. It is now possible to determine the routes over great distances and long periods of time with emerging monitoring networks. We tracked individual Swainson’s Thrush (Catharus ustulatus), Bicknell’s Thrush (Catharus bicknelli) and Gray-cheeked Thrush (Catharus minimus) in northeastern Quebec and compared their migration routes and paces across an array of radio-telelemetry stations in North America. Swainson’s Thrush migrated further inland than the other two species. Individuals from all three species slowed their migration pace in the southeastern United States, and Swainson’s Thrush was more likely to stopover than Bicknell’s Thrush. Although individuals were tagged in a small area within or close to their breeding range, the results document the variability of migration routes between species with similar ecological characteristics and provide detailed material to be used for migration studies with broader taxonomic or ecological scope

Atmospheric pressure predicts probability of departure for migratory songbirds

Abstract Background Weather can have both delayed and immediate impacts on animal populations, and species have evolved behavioral adaptions to respond to weather conditions. Weather has long been hypothesized to affect the timing and intensity of avian migration, and radar studies have demonstrated strong correlations between weather and broad-scale migration patterns. How weather affects individual decisions about the initiation of migratory flights, particularly at the beginning of migration, remains uncertain. Methods Here, we combine automated radio telemetry data from four species of songbirds collected at five breeding and wintering sites in North America with hourly weather data from a global weather model. We use these data to determine how wind profit, atmospheric pressure, precipitation, and cloud cover affect probability of departure from breeding and wintering sites. Results We found that the probability of departure was related to changes in atmospheric pressure, almost completely regardless of species, season, or location. Individuals were more likely to depart on nights when atmospheric pressure had been rising over the past 24 h, which is predictive of fair weather over the next several days. By contrast, wind profit, precipitation, and cloud cover were each only informative predictors of departure probability in a single species. Conclusions Our results suggest that individual birds actively use weather information to inform decision-making regarding the initiation of departure from the breeding and wintering grounds. We propose that birds likely choose which date to depart on migration in a hierarchical fashion with weather not influencing decision-making until after the departure window has already been narrowed down by other ultimate and proximate factors

Songbirds initiate migratory flights synchronously relative to civil dusk

Abstract Background Each spring and fall billions of songbirds depart on nocturnal migrations across the globe. Theory suggests that songbirds should depart on migration shortly after sunset to maximize their potential for nightly flight duration or to time departure with the emergence of celestial cues needed for orientation and navigation. Although captive studies have found that songbirds depart during a narrow window of time after sunset, observational studies have found that wild birds depart later and more asynchronously relative to sunset than predicted. Methods We used coded radio tags and automated radio-telemetry to estimate the time that nearly 400 individuals from nine songbird species departed their breeding or wintering grounds across North America. We also assessed whether each species was most likely beginning long-distance migratory flights at departure or instead first making non-migratory regional flights. We then explored variation in nocturnal departure time by post-departure movement type, species, age, sex, and season. Results We found that 90% of individuals from species that were likely initiating long-distance migratory flights departed within 69 min of civil dusk, regardless of species, season, age, or sex. By contrast, species that likely first made non-migratory regional movements away from the migratory destination departed later and more asynchronously throughout the night. Regardless of post-departure movement type, 98% of individuals departed after civil dusk but otherwise showed no preference in relation to twilight phase. Conclusions Although the presence of celestial orientation cues at civil dusk may set a starting point for departure each night, the fact that species likely beginning long-distance migration departed earlier and more synchronously relative to civil dusk than those first making non-migratory regional movements is consistent with the hypothesis that departing promptly after civil dusk functions to maximize the potential for nightly flight duration and distance. By studying the onset of migration, our study provides baseline information about departure decisions that may enhance our understanding of departure timing throughout migration