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Highly pathogenic avian influenza (HPAI) viruses pose a near-term threat to commercial poultry and a long-term risk for human pandemics (1,2). Recent outbreaks of HPAI A(H5N1) virus have also caused [...]

In 2022, a severe outbreak of disease caused by clade 2.3.4.4b Highly Pathogenic Avian Influenza (HPAI) H5N1 virus resulted in unprecedented mortality among wild birds in eastern Canada. Tens of thousands of birds were reported sick or dead, prompting a comprehensive assessment of mortality spanning the breeding season between April 1 and September 30, 2022. Mortality reports were collated from federal, Indigenous, provincial, and municipal agencies, the Canadian Wildlife Health Cooperative, and other nongovernmental organizations, universities, and citizen science platforms. A scenario analysis was conducted to refine mortality estimates, accounting for potential double counts from multiple sources under a range of spatial and temporal overlaps. Correcting for double counting, HPAI is estimated to have caused 40,391 wild bird mortalities in eastern Canada during the spring and summer of 2022; however, this figure underestimates total mortality as it excludes unreported deaths on land and at sea. Seabirds and sea ducks, long‐lived species that are slow to recover from perturbations, accounted for 98.7% of estimated mortalities. Our study provides estimates of bird mortality, with Northern Gannets (Morus bassanus; 25,669), Common Murres (Uria aalge; 8133), and American Common Eiders (Somateria mollissima dresseri; 1894) exhibiting the highest mortality figures. We then compare these mortality estimates with recent population estimates and trends and make an initial assessment of whether biologically meaningful population‐level impacts are possible. Specifically, we focus on the Northern Gannet, a species that has suffered significant global mortality, and two harvested species, Common Murre and American Common Eider, to inform management decisions. Our analysis suggests population‐level impacts in eastern Canada are possible for Northern Gannets and American Common Eiders, but are unlikely for Common Murres. This study demonstrates a comprehensive approach to assessing mortality and underscores the urgent need for further research to understand the broader ecological ramifications of the HPAI outbreak on wild bird populations. [ABSTRACT FROM AUTHOR]

Population declines of Leach's Storm Petrels Hydrobates leucorhous in the western Atlantic have both led to the species' recent assessment as Threatened in Canada and contributed to a Vulnerable designation by the IUCN. Limited information suggests low adult survival rates are an important contributing factor. Off eastern Nova Scotia, Canada, Country Island is managed for avian predators and mustelids to protect nesting endangered Roseate Terns Sterna dougallii. The island also hosts a colony of Leach's Storm Petrels. In 2016, a capture-markrecapture program was initiated for storm petrels, from which we estimated apparent survival and recapture probabilities for 571 breeding birds using data collected from 2016 to 2021. Models with a time-since-marking effect were consistently ranked higher than those without; annual apparent survival estimates in the first year after capture were lower than in subsequent years, presumably due to some captured birds not returning to the study area. Apparent survival in the years subsequent to first capture was lowest in forested areas with no understorey vegetation, slightly higher in forested areas with fern understorey, and highest in open areas with dense fern cover. While the mechanism driving habitat differences in adult survival is unknown, predation pressure may be strongest in forested areas with open understorey where it is easier for predators to find burrow entrances. Although apparent adult survival rates were higher than reported previously for nearby Bon Portage Island where predation is significant, Country Island may represent a best-case scenario for Leach's Storm Petrel in Atlantic Canada, since predators are managed and adult mortality from avian predators is relatively low at this site. Even so, survival rates at Country Island are lower than those reported previously at two Pacific colonies and provide evidence that adult survival rates of Leach's Storm Petrels in eastern Canada are depressed. [ABSTRACT FROM AUTHOR]

Reproduction in procellariiform birds is characterized by a single egg clutch, slow development, a long breeding season and obligate biparental care. Female Leach's Storm Petrels Hydrobates leucorhous, nearly monomorphic members of this order, produce eggs that are between 20 and 25% of adult bodyweight. We tested whether female foraging behaviour differs from male foraging behaviour during the ~ 44‐day incubation period across seven breeding colonies in the Northwest Atlantic. Over six breeding seasons, we used a combination of Global Positioning System and Global Location Sensor devices to measure characteristics of individual foraging trips during the incubation period. Females travelled significantly greater distances and went farther from the breeding colony than did males on individual foraging trips. For both sexes, the longer the foraging trip, the greater the distance. Independent of trip duration, females travelled farther, and spent a greater proportion of their foraging trips prospecting widely, as defined by behavioural categories derived from a hidden Markov Model. For both sexes, trip duration decreased with date. Sex differences in these foraging metrics were apparently not a consequence of morphological differences or spatial segregation. Our data are consistent with the idea that female foraging strategies differed from male foraging strategies during incubation in ways that would be expected if females were still compensating for egg formation. [ABSTRACT FROM AUTHOR]

Moult is an energetically demanding period, during which flight may be impaired and foraging ranges may become constrained. During the non‐breeding period, Great Ardenna gravis and Sooty Ardenna grisea Shearwaters migrate from South Atlantic breeding colonies to aggregate at North Atlantic feeding grounds. We investigated whether both shearwater species used coastal Newfoundland, Canada, as a moulting area and used stable isotope ratios (δ15N, δ13C) of recently moulted primary feathers (P1, P5, P10) to infer moult location/diet for both species. Moult scores indicated that both species finished their moult (i.e. P6–10) in coastal Newfoundland, which was further corroborated with similar stable isotope ratios for Great (δ15N = 15.17 ± 1.13‰; δ13C = −18.66 ± 0.54‰) and Sooty Shearwaters (15.54 ± 0.74‰; −18.43 ± 0.78‰); however, Sooty Shearwater moult was more advanced relative to that of Great Shearwater. In contrast, isotopic ratios of P1 and P5, which were grown before arriving in coastal Newfoundland, differed between and within species, suggesting divergent locations/diet during early moult. For Great Shearwaters, P1/P5 isotopic ratios were more variable (broader niche breadth) than P10, suggesting that some individuals started moulting in the South Atlantic prior to trans‐equatorial migration, whereas others start moulting in the North Atlantic Ocean. Sooty Shearwaters had two distinct groupings of either higher or lower δ15N in P1/P5, suggesting that individuals began moulting either on the Newfoundland Shelf or further offshore based on comparisons to reference shearwater feathers grown in known locations. These findings illustrate distinct locations and/or diets at the start of primary feather moult, both within and between species, but diets converged when aggregated together at the end of moult in coastal North America, where growing feathers of both species were sampled. More importantly, we identified an important area for both Sooty and Great Shearwaters to complete their moult in coastal Newfoundland. Protecting this moulting area would minimize disturbance and the impacts of threats (e.g. by‐catch) to both species during this energetically demanding period. The area has been suggested previously to be an important candidate area for protection due to annually persistent prey aggregations that can be spatiotemporally delimited based on specific prey habitat requirements. [ABSTRACT FROM AUTHOR]

Nest platforms (mossy pads, limbs, and deformities >15 cm in diameter) are key requirements in the forest nesting habitat of the threatened Marbled Murrelet (Brachyramphus marmoratus (J.F. Gmelin, 1789)). Little is known about factors that affect the availability of platforms or the growth of canopy epiphytes that provide platforms. We examined variables affecting these parameters in coastal trees in British Columbia using data from 29 763 trees at 1412 sites in 170 watersheds. Tree diameter (diameter at breast height (DBH)) was the most important predictor of platform availability in the pooled data and within each of six regions. In most regions, platforms become available at DBH > 60 cm, but on East Vancouver Island, DBH needs to be >96 cm and possibly on the Central Coast >82 cm. Other regional predictors of platforms included tree height, tree species, and to a lesser extent elevation, slope, and latitude. Most (72%) trees providing platforms had epiphytes (mainly moss) covering one third or more of branch surfaces and 81% had intermediate or thick epiphyte mats. Mistletoe deformities provided Resume: Les plateformes de nidification (coussins de mousse, branches et difformites >15 cm de diametre) constituent des attributs indispensables de l'habitat forestier de nidification de l'alque marbree (Brachyramphus marmoratus (J.F. Gmelin, 1789)), une espece menacee. On sait peu de choses des facteurs qui affectent la disponibilite des plateformes ou la croissance des epiphytes de la canopee qui fournissent des plateformes. Nous avons examine les variables qui affectent ces parametres chez les arbres cotiers de la Colombie-Britannique en utilisant les donnees de 29 763 arbres repartis dans 1 412 sites et 170 bassins versants. Le diametre des arbres (le diametre a la hauteur de poitrine (DHP)) etait la meilleure variable predictive de la disponibilite de plateformes que toutes les donnees soient regroupees ou dans chacune des six regions d'ou provenaient ces donnees. Dans la plupart des regions, des plateformes devenaient disponibles quand le DHP depassait 60 cm, mais dans l'est de l'ile de Vancouver le DHP devait etre >96 cm, et possiblement >82 cm dans la region de la Cote Centrale. Les autres variables predictives des plateformes dans les modeles regionaux incluaient la hauteur de l'arbre, l'essence et, a un moindre degre, l'altitude, la pente et la latitude. La plupart (72 %) des arbres fournissant des plateformes avaient des epiphytes (surtout des mousses) sur au moins un tiers de la surface des branches et 81% avaient des coussins d'epiphytes moyens ou epais. Les difformites causees par le gui ont fourni [Traduit par la Redaction], Introduction Many ecological studies, especially those linked with forest management and habitat mapping, focus on coarse-scale correlates and predictors of an organism's habitat needs (Manly et al. 2002; Scott et [...]

Gulls are ubiquitous in urban areas due to a growing reliance on anthropogenic feeding sites, which has led to changes in their abundance, distribution, and migration ecology, with implications for disease transmission. Gulls offer a valuable model for testing hypotheses regarding the dynamics of influenza A virus (IAV) – for which gulls are a natural reservoir in urban areas. We sampled sympatric populations of Ring‐billed (Larus delawarensis), Herring (L. argentatus), and Great Black‐backed Gulls (L. marinus) along the densely populated Atlantic rim of North America to understand how IAV transmission is influenced by drivers such as annual cycle, host species, age, habitat type, and their interplay. We found that horizontal transmission, rather than vertical transmission, played an outsized role in the amplification of IAV due to the convergence of gulls from different breeding grounds and age classes. We detected overlapping effects of age and season in our prevalence model, identifying juveniles during autumn as the primary drivers of the seasonal epidemic in gulls. Gulls accumulated immunity over their lifespan, however short‐term fluctuations in seroprevalence were observed, suggesting that migration may impose limits on the immune system to maintain circulating antibodies. We found that gulls in coastal urban habitats had higher viral prevalence than gulls captured inland, correlating with higher richness of waterbird species along the coast, a mechanism supported by our movement data. The peak in viral prevalence in newly fledged gulls that are capable of long‐distance movement has important implications for the spread of pathogens to novel hosts during the migratory season as well as for human health as gulls increasingly utilize urban habitats. [ABSTRACT FROM AUTHOR]

Copyright of Avian Conservation & Ecology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Avian Conservation & Ecology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Opportunist gulls use anthropogenic food subsidies, which can bolster populations, but negatively influence sensitive local ecosystems and areas of human settlement. In the eastern Gulf of Maine, Canada, breeding herring gulls Larus argentatus have access to resources from aquaculture, fisheries and mink farms, but the relative influence of industry on local gull populations is unknown. Our objectives were to 1) assess use of natural and anthropogenic habitats by herring gulls from multiple colonies, 2) evaluate variation among colonies in use of distinct resource types within these habitats and 3) highlight areas of high gull:industry interaction. Using GPS devices on 39 gulls from four colonies, we identified visitation behaviour (slow, localized movements) and assigned visits to nine resource types. To evaluate the spatial distribution of visits, we created a use intensity index, reflecting both fidelity (i.e. repeated visits) and time spent in specific areas. All four anthropogenic resource types were heavily used (56 ± 11% of visiting time across colonies), notably, fish plants and mink farms. Despite large distances among three colonies, birds overlapped at particular distant, inland mink farms. In contrast, birds from close colonies overlapped in visitation to specific nearby resources (e.g. fish plants and human settlement), and otherwise diverged in distribution and use of offshore and coastal areas. Birds from three colonies also made frequent, long visits to uninhabited islands. Industry is clearly influencing the behaviour of breeding gulls in the eastern Gulf of Maine, Canada, where birds are travelling great distances or spending large proportions of time interacting with anthropogenic resources, while otherwise paying lengthy visits to nearby coastal islands. Studies have shown that concentrations of gulls can have harmful direct and indirect ecological and societal impacts. Our findings have implications for the management and regulation of industry to mitigate detrimental effects on local ecosystems and humans. [ABSTRACT FROM AUTHOR]

Understanding the movements of seabirds, which are important ecological indicators, can provide new insights into physical and biological aspects of the marine environment. This information can also be used in planning marine conservation and oil spill response strategies. Though Black Guillemots Cepphus grylle are widely distributed in the coastal waters of eastern and arctic Canada, little is known about their movements during the non-breeding season. We used a combination of global location sensors and stable-isotope analyses on Black Guillemots breeding on Country Island, Nova Scotia, Canada and on Kent Island, New Brunswick, Canada to examine their non-breeding movements and trophic ecology in 2017-2018. Overall, the two populations dispersed an average of 157 km from their breeding colonies (max. 494 km) throughout the region, reaching areas that included the Scotian Shelf, Gulf of St. Lawrence, Bay of Fundy, and Gulf of Maine; both populations overlapped in the Bay of Fundy during the winter. Trophic levels (d15N) and foraging locations (δ13C) differed between the colonies. Birds from Country Island foraged at higher trophic levels and in less benthic waters than Kent Island birds overall, and birds from both colonies foraged at higher trophic levels in autumn than in winter. This indicates that foraging strategies differ between Black Guillemot populations and that diet varies between seasons, even when foraging habitats do not. Our findings, combined with other seabird, fish, and marine mammal tracking studies, can inform marine management decisions in Atlantic Canada. [ABSTRACT FROM AUTHOR]

The American common eider Somateria mollissima dresseri is a sea duck of coastal mid-Atlantic North America, and breeding colonies in the southern part of its range have been in decline. To better understand threats faced by the subspecies, we used satellite telemetry to track 46 eiders through their annual cycle in four years from three regions in the southern part of the range, to identify key locations and migratory corridors. Female eiders exhibited highly variable movement phenology within and among colonies, but coastal Maine and Massachusetts were consistent, important moulting areas for males and females from all breeding colonies. Most birds wintered in coastal waters around Cape Cod and Nantucket Sound, meaning that threats in this region (industrial development, disease outbreak, harvest) could have deleterious effects on much of the population. [ABSTRACT FROM AUTHOR]

Copyright of Avian Conservation & Ecology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Inaccessible Island, in the Tristan da Cunha archipelago, is the sole breeding site of the Spectacled Petrel Procellaria conspicillata. The island also supports globally important populations of four threatened seabirds, as well as populations of other seabird species. A seabird monitoring protocol was established in 2004, following baseline surveys of most surface-breeding species in 1999. For the species monitored, we report population trends that are based on visits in 2009 and 2018. Populations of most monitored species appear to be stable or increasing, including three albatross species currently listed as Endangered or Critically Endangered. However, numbers of Northern Rockhopper Penguin Eudyptes moseleyi may have decreased slightly since 1999, and numbers of Antarctic Tern Sterna vittata have decreased since 1982. The population of Spectacled Petrels is estimated to be at least 30 000 pairs and continues to increase since feral pigs Sus scrofa died out on the island in the early 20th century. We describe a new monitoring protocol for Spectacled Petrels that will be easier to repeat and implement and that should provide a more sensitive measure of future population changes. [ABSTRACT FROM AUTHOR]

Little is known about the movements of small seabirds during migration, but such information is important for their conservation. Leach's Storm Petrel Oceanodroma leucorhoa is the most abundant seabird in Atlantic Canada, but its population has declined in recent years. Here, we describe trans-equatorial and trans-Atlantic migration movements of 13 Leach's Storm Petrels, which were tracked with geolocators from two breeding colonies in Nova Scotia, Canada: Bon Portage Island and Country Island. Our results indicate that Leach's Storm Petrels have low migratory connectivity and that they use multiple stopover areas and overwintering destinations. Birds with stopover areas at higher latitudes overwintered in the North Atlantic Ocean, either in areas associated with the North Equatorial Current or in waters off Newfoundland and Labrador. Birds with lower-latitude stopover areas overwintered in the South Atlantic Ocean, in areas associated with the Benguela Current off southwestern Africa. We observed greater δ15N values (indicating a higher trophic level) in feathers from birds that migrated south compared to birds that stayed in the Northern Hemisphere, but we observed no difference in δ13C (which may be interpreted in multiple ways). Species distribution modelling using remotely sensed oceanographic data indicated that high sea surface temperatures and high chlorophyll a concentrations were important predictors of habitat use in winter. [ABSTRACT FROM AUTHOR]