Diversité, abondance et répartition des oiseaux aquatiques hivernant dans les eaux côtières et pélagiques du Parc marin Saguenay–Saint-Laurent

Le parc marin Saguenay–Saint-Laurent (PMSSL) est situé dans l’une des zones les plus productives de l’estuaire du Saint-Laurent et supporte des nombres importants d’oiseaux aquatiques à l’année longue. Malgré ce fait, aucune étude détaillée n’a encore été faite sur l’utilisation des habitats côtiers de cette région par l’avifaune en hiver. Pour combler cette lacune, des inventaires aériens et terrestres ont été effectués pour mieux quantifier la répartition, l’abondance et le comportement des oiseaux aquatiques hivernant dans le PMSSL. Les résultats confirment l’importance du PMSSL pour les oiseaux aquatiques hivernant dans l’estuaire du Saint-Laurent et indiquent aussi que les oiseaux se déplacent à l’intérieur du PMSSL en fonction des marées, de l’état des glaces et des vents. Les espèces de canards les plus abondantes incluent le Harelde kakawi (Clangula hyemalis), le Harle huppé (Mergus serrator), le Garrot à oeil d’or (Bucephala clangula), le Garrot d’Islande (B. islandica) et le Canard noir (Anas rubripes). Quatre espèces de goélands s’y retrouvent en abondance, soit le Goéland arctique (Larus glaucoides), bourgmestre (L. hyperboreus), argenté (L. argentatus) et marin (L. marinus). On note aussi la présence de Guillemots à miroir (Cepphus grylle) en milieu pélagique, de Bécasseaux violets (Calidris maritima) sur les îles et îlots du large et de quelques Petits Garrots (Bucephala albeola). Les données des recensements d’oiseaux de Noël suggèrent une augmentation des effectifs de Canards noirs, Canards colverts (Anas plathyrynchos), Garrots d’Islande et Harles huppés. Par contre, on a observé un nombre inférieur de Hareldes kakawis ces dernières années.The Saguenay–St. Lawrence Marine Park (PMSSL) is located in one of the most productive areas of the St. Lawrence and supports large numbers of aquatic birds all year round. Nevertheless, there is no detailed study on the use of this area by aquatic birds in winter. So, to rectify the situation, aerial and ground surveys were done to better quantify the distribution, abundance and behaviour of aquatic birds wintering in the PMSSL. Results confirm the importance of the PMSSL for aquatic birds wintering in the St. Lawrence estuary, and establish that birds move within the PMSSL in relation to tides, ice conditions and winds. The most numerous waterfowl species are the Long-tailed Duck (Clangula hyemalis), the Red-breasted Merganser (Mergus serrator), the Common Goldeneye (Bucephala clangula), the Barrow’s Goldeneye (B. islandica) and the Black Duck (Anas rubripes). Four species of gulls winter there in great numbers: the Arctic Gull (Larus glaucoides), the Glaucous Gull (L. hyperboreus), the Herring Gull (L. argentatus) and the Great Black-backed Gull (L. marinus). Black Guillemots (Cepphus grylle) were also present offshore, as well as Purple Sandpipers (Calidris maritima) on the offshore islands and shoals, and a small number of Buffleheads (Bucephala albeola). Christmas Bird Count Data suggest an increase in wintering populations of Black Ducks, Mallards (Anas plathyrynchos), Barrow’s Goldeneyes and Red-breasted Mergansers. However, large flocks of Long-tailed Ducks have been less frequent in recent years

Avian mortalities due to transmission line collisions: a review of current estimates and field methods with an emphasis on applications to the Canadian electric network

Birds are vulnerable to collisions with human-made fixed structures. Despite ongoing development and increases in infrastructure, we have few estimates of the magnitude of collision mortality. We reviewed the existing literature on avian mortality associated with transmission lines and derived an initial estimate for Canada. Estimating mortality from collisions with power lines is challenging due to the lack of studies, especially from sites within Canada, and due to uncertainty about the magnitude of detection biases. Detection of bird collisions with transmission lines varies due to habitat type, species size, and scavenging rates. In addition, birds can be crippled by the impact and subsequently die, although crippling rates are poorly known and rarely incorporated into estimates. We used existing data to derive a range of estimates of avian mortality associated with collisions with transmission lines in Canada by incorporating detection, scavenging, and crippling biases. There are 231,966 km of transmission lines across Canada, mostly in the boreal forest. Mortality estimates ranged from 1 million to 229.5 million birds per year, depending on the bias corrections applied. We consider our most realistic estimate, taking into account variation in risk across Canada, to range from 2.5 million to 25.6 million birds killed per year. Data from multiple studies across Canada and the northern U.S. indicate that the most vulnerable bird groups are (1) waterfowl, (2) grebes, (3) shorebirds, and (4) cranes, which is consistent with other studies. Populations of several groups that are vulnerable to collisions are increasing across Canada (e.g., waterfowl, raptors), which suggests that collision mortality, at current levels, is not limiting population growth. However, there may be impacts on other declining species, such as shorebirds and some species at risk, including Alberta's Trumpeter Swans (Cygnus buccinator) and western Canada's endangered Whooping Cranes (Grus americana). Collisions may be more common during migration, which underscores the need to understand impacts across the annual cycle. We emphasize that these estimates are preliminary, especially considering the absence of Canadian studies

A comparison between nocturnal aural counts of passerines and radar reflectivity from a Canadian weather surveillance radar

Using a Canadian weather surveillance radar (CWSR), we assessed the relationship between aural passerine counts and radar reflectivity during autumn migration on 16 nights. Reflectivity was positively correlated on all but 1 night with the number of birds detected aurally, but the correlation strength varied between -0.58 and 0.93 among nights (mean ± SD = 0.69 ± 0.42). Using linear mixed-effects models with aural counts nested within nights, we found that the number of birds detected by observers increased with reflectivity. The slope of this relationship did not vary between observers, nor was it affected by time since sunset, but the number of birds detected aurally tended to be lower when ambient noise levels were high. We know that the radar was relatively sensitive to low bird densities, because the intercept was slightly positive and its 95% confidence interval marginally included zero. However, the relationship between the number of birds detected aurally and reflectivity varied significantly among nights. Such variation was likely caused by a combination of (interacting) factors, including bird species and behavior (e.g., calling rate, flight altitude), influencing bird detectability by the observers and the radar. The weather radar network of the United States (NEXRAD) is already used for bird migration studies, and we conclude that the use of CWSR can extend NEXRAD's coverage farther north by hundreds of kilometers, thereby increasing our understanding of how birds use the North American landscapes during migration. Nous avons étudié la relation entre un dénombrement auditif de passereaux et la réflectivité d'un radar de surveillance météorologique canadien (CWSR), durant la migration automnale, pendant 16 nuits. La réflectivité radar était positivement corrélée avec le nombre d'oiseaux détectés auditivement pour toutes les nuits, exception d'une, mais la puissance de cette relation variait de -0.58 à 0.93 (moyenne ± écart-type = 0.69 ± 0.42). En utilisant des modèles linéaires à effets mixtes où les dénombrements auditifs étaient nichés de manière intra-nuit, nous avons confirmé que le nombre d'oiseaux détectés par les observateurs s'accroissait avec la réflectivité. La pente de cette relation ne variait pas entre les observateurs comme elle n'était pas affectée par le temps écoulé depuis le coucher du soleil, mais le nombre d'oiseaux détectés auditivement tendait àdiminuer quand le bruit ambiant était plus élevé. Le radar s'est avéré être relativement sensible à une faible densité d'oiseaux, puisque la valeur de l'intercepte était légèrement positive et ses intervalles de confiance de 95% incluaient marginalement le zéro. Cependant, la relation entre le nombre d'oiseaux détectés auditivement et la réflectivité variait significativement entre les nuits. Une telle variation est vraisemblablement attribuable à la combinaison (ou l'interaction) de facteurs incluant les espèces d'oiseaux présentes et leurs comportements (e.g. taux de cris, altitude de vol), ce qui influence la détectabilité des oiseaux par les observateurs, mais aussi par le radar. Le réseau de radars météo (NEXRAD) des États-Unis est déjà utilisé dans des études de la migration des oiseaux et nous concluons que l'utilisation des CWSR pourrait permettent une extension vers le nord de plusieurs centaines de kilomètres de la couverture du réseau NEXRAD, permettant d'accroître la compréhension de l'utilisation des paysages nord américains par les oiseaux durant leur migration

Landscape-scale disturbances and changes in bird communities of boreal mixed-wood forests

Bird community response to both landscape-scale and local (forest types) changes in forest cover was studied in three boreal mixed-wood forest landscapes modified by different types of disturbances: (1) a pre-industrial landscape where human settlement, agriculture, and logging activities date back to the early 1930s, (2) an industrial timber managed forest, and (3) a forest dominated by natural disturbances. Birds were sampled at 459 sampling stations distributed among the three landscapes. Local habitat and landscape characteristics of the context surrounding each sampling station (500-m and 1-km radius) were also computed. Bird communities were influenced by landscape-scale changes in forest cover. The higher proportion of early-successional habitats in both human-disturbed landscapes resulted in significantly higher abundance of early-successional bird species and generalists. The mean number of mature forest bird species was significantly lower in the industrial and pre-industrial landscapes than in the natural landscape. Landscape-scale conversion of mature forests from mixed-wood to deciduous cover in human-disturbed landscapes was the main cause of changes in mature forest bird communities. In these landscapes, the abundance of species associated with mixed and coniferous forest cover was lower, whereas species that preferred a deciduous cover were more abundant. Variation in bird community composition determined by the landscape context was as important as local habitat conditions, suggesting that predictions on the regional impact of forest management on songbirds with models solely based on local scale factors could be misleading. Patterns of bird species composition were related to several landscape composition variables (proportions of forest types), but not to configuration variables (e.g., interior habitat, amount of edge). Overall, our results indicated that the large-scale conversion of the southern portion of the boreal forest from a mixed to a deciduous cover may be one of the most important threats to the integrity of bird communities in these forest mosaics. Negative effects of changes in bird communities could be attenuated if current forestry practices are modified toward maintaining forest types (deciduous, mixed-wood, and coniferous) at levels similar to those observed under natural disturbances

Weather effects on autumn nocturnal migration of passerines on opposite shores of the St. Lawrence estuary

We modeled migration intensity as a function of weather, using nightly migration measurements from Doppler surveillance weather radar during autumn migration on the north (Côte-Nord) and south (Gaspésie) shores of the St. Lawrence estuary, Québec, Canada. The radar had negative elevation angles, an uncommon characteristic among weather radars, which allowed simultaneous low-altitude monitoring of bird migration on each side of the estuary. Precipitation and wind both had strong effects on the intensity of migration. Very few birds migrated when >40% of the area had precipitation, especially when winds were strong. Light winds were associated with the strongest migration intensity, regardless of wind direction; in stronger winds, migration was likely only when winds were predominantly from the north. Days immediately after adverse weather events, which are assumed to lead to an accumulation of migrants, were associated with an increase in the intensity of migration in Côte-Nord, but not in Gaspésie. Time since the passage of a cold front had no effect in either region. Bird flight direction and behavior in relation to wind differed on each side of the estuary. On Côte-Nord, birds tended to migrate in a southwesterly direction along the St. Lawrence north coast, in a direction relatively unaffected by wind direction; they compensated or overcompensated for wind drift by following the coast. By contrast, birds in Gaspésie tended to fly in a more southerly direction. They migrated partially or almost fully downwind with only limited compensation, their flight direction often changing with wind direction. Nous avons modélisé l'intensité migratoire automnale en fonction de la météo, en utilisant des mesures de la migration nocturne prises à la fois sur la rive nord (Côte-Nord) et la rive sud (Gaspésie) de l'estuaire du Saint-Laurent, Québec, Canada, à l'aide d'un radar Doppler de surveillance météorologique. Ce radar effectue des balayages à des angles négatifs, une caractéristique rare chez les radars météo qui permet entre autres, de relever des données de migration d'oiseaux à basse altitude et simultanément de chaque côté de l'estuaire. Nos résultats montrent que les précipitations et le vent avaient de forts effets sur l'intensité migratoire. Peu d'oiseaux migraient quand 40% ou plus du territoire était affecté par des précipitations, particulièrement en combinaison avec des vents forts. Les plus fortes intensités migratoires étaient associés avec des vents légers, peu importe la direction du vent; par vents forts, la migration était plus probable quand les vents avaient une composante nord. Un événement de conditions météo adverses à la migration s'ensuivait d'une augmentation de l'intensité migratoire sur la Côte-Nord, mais pas en Gaspésie. Le passage d'un front froid n'avait aucun effet sur la migration dans l'une ou l'autre des deux régions. La direction de vol des oiseaux et leur comportement relativement au vent différaient de chaque côté de l'estuaire. Sur la Côte-Nord, les oiseaux avaient tendance à migrer vers Ie sud-ouest, Ie long de la rive nord du Saint-Laurent; cette direction de vol était peu affectée par la direction du vent et les oiseaux suivaient la côte en compensant ou surcompensant pour la dérive par les vents. En opposition, les oiseaux en Gaspésie avaient tendance à voler vers Ie sud; leur migration se faisait en suivant partiellement ou pleinement le vent avec peu de compensation et avec une direction de vol qui changeait souvent avec la direction du vent

Habitat Use by Brood-Rearing Waterfowl in Subarctic Québec

Aerial surveys of waterfowl were conducted in subarctic Quebec in 1989 and 1990 on randomly selected 100 sq km plots. We used logistic regression for modelling relationships betweren the presence of waterfowl broods and habitat characteristics. For each species, models of habitat use were generated with one data set and tested with two others. We also compared the frequency distributions of broods of each species in different habitat types. Correct-classification rates of models varied betweren 0.53 and 0.77. Sensitivity of models generally increased when applied to validation data sets. Models showed that green-winged teals (Anas crecca) avoided lakes >501 ha and used vegetated lakes, ponds and fens or bogs more than predicted by their availability. Black scoters (Melanitta nigra) and surf scoters (M. perspicillata) were found mostly on small lakes (<10 ha) and medium lakes (10-100 ha). Black scoters were associated with the presence of ponds and lakes with sedge and grass, whereas surf scoters were not. The presence of scaup (Aythia spp.) broods was associated with the presence of vegetation. Green-winged teals were observed more often on bogs than were either scoters or scaups. Black scoters were observed more often on ponds and less often on medium-sized lakes than surf scoters and scaups. The latter differed in their use of lakes <10 ha: surf scoters, like black scoters, mostly used unvegetated lakes, while scaups and green-winged teals mostly used vegetated lakes. The accuracy and precision of logistic models may be enhanced by additional habitat variables, careful selection of sample-cell size and further investigation of the breeding biology of the surveyed species.Key words: habitat, model, logistic regression, northern Québec, black scoter, surf scoter, green-winged teal, scaup, broodDes inventaires aériens de sauvagine dans des parcelles de 100 km² sélectionnées aléatoirement ont été réalisés dans le Québec subarctique en 1989 et en 1990. La régression logistique fut utilisée pour modéliser les relations entre la présence de couvées et des paramètres d'habitat. Des modèles d'utilisation d'habitat ont été générés à l'aide d'une série de données et validés à l'aide de deux autres. Nous avons aussi comparé les distributions de fréquences des couvées des espèces étudiées dans divers types de biotopes. Les taux de classification correcte des modèles ont varié entre 0.53 et 0.77. De façon générale, la sensibilité des modèles augmentait lorsque ces derniers étaient appliqués aux données de validation. Les modèles montrent que la Sarcelle à ailes vertes (Anas crecca) a utilisé les plans d'eau avec de la végétation, les étangs et les tourbières et a évité les lacs > 501 ha. Les macreuses (Melanitta nigra, M. perspicillata) ont surtout été vues sur des lacs de petite (< 10 ha) et moyenne (10-100 ha) superficies. Les Macreuses à bec jaune se démarquaient des Macreuses à front blanc en étant associées à la présence d'étangs et de lacs avec des herbaçaies. La présence de couvées de morillons (Aythia spp.) dans les cellules était associée à celle de végétation. La Sarcelle à ailes vertes fut observée plus souvent dans les tourbières que les autres espèces. La Macreuse à bec jaune fut observée plus souvent sur des étangs et moins souvent sur des lacs de superficie moyenne que la Macreuse à front blanc et les morillons. Ces dernières espèces différaient dans leur utilisation de lacs <10 ha: les Macreuses à front blanc, comme les Macreuses à bec jaune, utilisaient surtout les lacs aux rives sans végétation alors que les morillons et les sarcelles utilisaient surtout des lacs avec végétation. La précision des modèles de régression logistique pourrait être augmentée par l'utilisation de paramètres d'habitat supplémentaires, un choix différent de la taille de l'unité de mesure et une meilleure connaissance de l'écologie des espèces cibles.Mots clés: habitat, modèle, régression logistique, Québec, Macreuse à bec jaune, Macreuse à front blanc, Sarcelle à ailes vertes, Morillons, couvé

Molting, Staging, and Wintering Locations of Common Eiders Breeding in the Gyrfalcon Archipelago, Ungava Bay

The northern common eider (Somateria mollissima borealis) has become a source of concern because of recent declines and possible overharvest. Birds that breed in the Canadian mid-Arctic winter in both Greenland and Canada, but the wintering grounds of birds that breed farther south are unknown. Our objectives were thus to identify the molting and wintering areas of birds breeding in Ungava Bay and to compare their home-range sizes during the pre-molt, molt, post-molt, and winter periods. Using satellite telemetry, we determined that common eiders breeding in the lower Arctic winter in Greenland (67%) and Canada (33%). These proportions are consistent with the split established for common eiders that breed farther north. Females spent their pre-molt period close to their breeding islands and had the smallest home ranges during the molt period. Winter home ranges were larger in Canada than in Greenland, probably because they contained more ice. Once settled, birds wintered in a relatively small area and did not undertake long movements. Distance between molt and winter sites ranged between 1054 and 2173 km. Duration of migration to or from wintering areas varied among individuals from rapid movement in a few days to slow progress over a month. Fall migration occurred in late October or early November, and spring migration, in early to mid-May. This study highlights the importance of Ungava Bay for northern common eiders and the need for international collaboration to ensure sustainable use of the resource.L’eider à duvet du nord (Somateria mollissima borealis) représente une source de préoccupation en raison de déclins récents et de récoltes susceptibles d’être excessives. Les oiseaux nichant dans la zone arctique moyenne canadienne hivernent au Groenland et au Canada, mais l’aire d’hivernage des oiseaux nichant plus au sud n’est pas connue. Nos objectifs consistaient donc à identifier les aires de mue et d’hivernage des oiseaux nichant dans la baie d’Ungava et de comparer leur aire d’activité lors des périodes de pré-mue, de mue, d’après-mue et d’hiver. Au moyen de la télémétrie satellitaire, nous avons déterminé que l’eider à duvet nichant dans la zone arctique inférieure hiverne au Groenland (67 %) et au Canada (33 %). Ces proportions sont similaires à celles trouvées dans les colonies d’eider à duvet plus nordiques. Les femelles passent la période de la pré-mue près de leurs îles de nidification et sont les plus restreintes en termes d’aire utilisée lors de la période de mue. Les aires d’activité hivernale étaient plus grandes au Canada qu’au Groenland, probablement en raison de la plus grande présence de glaces au Canada. Une fois sur leur site d’hivernage, les oiseaux évoluaient dans une aire relativement petite et n’entreprenaient pas de longs déplacements. La distance entre les sites de mue et d’hivernage variait entre 1 054 et 2 173 kilomètres. La durée de la migration variait d’un individu à l’autre, allant de déplacements rapides sur quelques jours à des déplacements plus lents sur près d’un mois. La migration automnale a débuté à la fin octobre, début novembre et celle du printemps vers le début et la mi-mai. Cette étude met en évidence la grande importance de la baie d’Ungava pour l’eider à duvet du nord de même que le besoin de collaboration internationale pour assurer l’utilisation soutenue de cette ressource

Premium food for offspring? Black-backed Woodpecker (Picoides arcticus) diet during breeding season in eastern Canada

Knowledge on the diet of the Black-backed Woodpecker (Picoides arcticus Swainson, 1832) is fragmentary and relies on a limited number of studies. Gaps remain in our understanding of the plasticity of its diet, particularly in the eastern part of its range. The main objective of this study was to assess the diet of Black-backed Woodpeckers in burned and unburned habitats and among sexes and ages in Québec. We collected feces and fecal bags from unburned and burned habitats in the Central Laurentians ecoregion of the eastern boreal shield ecozone and assessed diets based on identified prey items. Buprestidae and Cerambycidae of the sub-family Lamiinae were the predominant prey for adult Black-backed Woodpeckers in burned habitats, and the Pythidae Pytho niger (Kirby, 1837) and Lamiinae were the most prevalent prey in unburned habitats. Lamiinae were the most predominant prey items provisioned to nestling in burned habitat, while P. niger was their predominant food in unburned habitat, followed by Cerambycidae (without Lamiinae) and Lamiinae. Our results present new insights into Black-backed Woodpecker diet where parents feed their offspring with the largest prey available, potentially providing higher fitness for their offspring. Furthermore, our study confirms that Black-backed Woodpeckers, at least in the eastern part of its range, are not restricted to feed on Lamiinae but are rather opportunistic in taking advantage from resource–pulse interactions provided by recently disturbed habitats, especially from recently burned habitats

Spatially Explicit Network Analysis Reveals Multi‐Species Annual Cycle Movement Patterns of Sea Ducks

Conservation of long‐distance migratory species poses unique challenges. Migratory connectivity, that is, the extent to which groupings of individuals at breeding sites are maintained in wintering areas, is frequently used to evaluate population structure and assess use of key habitat areas. However, for species with complex or variable annual cycle movements, this traditional bimodal framework of migratory connectivity may be overly simplistic. Like many other waterfowl, sea ducks often travel to specific pre‐ and post‐breeding sites outside their nesting and wintering areas to prepare for migration by feeding extensively and, in some cases, molting their flight feathers. These additional migrations may play a key role in population structure, but are not included in traditional models of migratory connectivity. Network analysis, which applies graph theory to assess linkages between discrete locations or entities, offers a powerful tool for quantitatively assessing the contributions of different sites used throughout the annual cycle to complex spatial networks. We collected satellite telemetry data on annual cycle movements of 672 individual sea ducks of five species from throughout eastern North America and the Great Lakes. From these data, we constructed a multi‐species network model of migratory patterns and site use over the course of breeding, molting, wintering, and migratory staging. Our results highlight inter‐ and intra‐specific differences in the patterns and complexity of annual cycle movement patterns, including the central importance of staging and molting sites in James Bay, the St. Lawrence River, and southern New England to multi‐species annual cycle habitat linkages, and highlight the value of Long‐tailed Ducks (Calengula haemalis) as an umbrella species to represent the movement patterns of multiple sea duck species. We also discuss potential applications of network migration models to conservation prioritization, identification of population units, and integrating different data streams

Implanted Satellite Transmitters Affect Sea Duck Movement Patterns at Short and Long Timescales

Studies of the effects of transmitters on wildlife often focus on survival. However, sublethal behavioral changes resulting from radio-marking have the potential to affect inferences from telemetry data and may vary based on individual and environmental characteristics. We used a long-term, multi-species tracking study of sea ducks to assess behavioral patterns at multiple temporal scales following implantation of intracoelomic satellite transmitters. We applied state-space models to assess short-term behavioral patterns in 476 individuals with implanted satellite transmitters, as well as comparing breeding site attendance and migratory phenology across multiple years after capture. In the short term, our results suggest an increase in dispersive behavior immediately following capture and transmitter implantation; however, behavior returned to seasonally average patterns within ~5 days after release. Over multiple years, we found that breeding site attendance by both males and females was depressed during the first breeding season after radio-marking relative to subsequent years, with larger relative decreases in breeding site attendance among males than females. We also found that spring and breeding migrations occurred later in the first year after radio-marking than in subsequent years. Across all behavioral effects, the severity of behavioral change often varied by species, sex, age, and capture season. We conclude that, although individuals appear to adjust relatively quickly (i.e. within 1 week) to implanted satellite transmitters, changes in breeding phenology may occur over the longer term and should be considered when analyzing and reporting telemetry data