Climate change imposes physiological constraints on organisms particularly through changing thermoregulatory requirements. Bergmann's and Allen's rules suggest that body size and the size of ...thermoregulatory structures differ between warm and cold locations, where body size decreases with temperature and thermoregulatory structures increase. However, phenotypic plastic responses to malnutrition during development can result in the same patterns while lacking fitness benefits. The Gulf of Maine (GOM), located at the southern end of the Labrador current, is warming faster than most of the world's oceans, and many of the marine species that occupy these waters exist at the southern edge of their distributions including Atlantic puffins (Fratercula arctica; hereafter "puffin"). Monitoring of puffins in the GOM, at Machias Seal Island (MSI), has continued annually since 1995. We asked whether changes in adult puffin body size and the proportional size of bill to body have changed with observed rapid ocean warming. We found that the size of fledgling puffins is negatively related to sea surface temperature anomalies (warm conditions = small fledgers), adult puffin size is related to fledgling size (small fledgers = small adults), and adult puffins have decreased in size in recent years in response to malnutrition during development. We found an increase in the proportional size of bill to wing chord, likely in response to some mix of malnutrition during development and increasing air temperatures. Although studies have assessed clinal variation in seabird morphology with temperature, this is the first study addressing changes in seabird morphology in relation to ocean warming. Our results suggest that puffins nesting in the GOM have morphological plasticity that may help them acclimate to ocean warming.
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Research in remote locations is more expensive than similar activities at sites with easier access, but these costs have rarely been compared. Using examples from seabird research, we show that ...conducting research in the Arctic is typically eight times more expensive than pursuing similar studies at a southern location. The differences in costs are related principally to the much higher expenses of travel and shipping (typically 4–10× higher for Arctic work), as well as the good practice of meaningful engagement with northern communities (4%–25% of project costs). Although there is some variation in costs among Arctic countries, we hope that the consistent pattern of relatively higher Arctic costs allows policy-makers and funding agencies to better plan for research support, especially for this region that is experiencing rapid environmental change.
Each winter, the North Atlantic Ocean is the stage for numerous cyclones, the most severe ones leading to seabird mass-mortality events called “winter wrecks.”1–3 During these, thousands of emaciated ...seabird carcasses are washed ashore along European and North American coasts. Winter cyclones can therefore shape seabird population dynamics4,5 by affecting survival rates as well as the body condition of surviving individuals and thus their future reproduction. However, most often the geographic origins of impacted seabirds and the causes of their deaths remain unclear.6 We performed the first ocean-basin scale assessment of cyclone exposure in a seabird community by coupling winter tracking data for ∼1,500 individuals of five key North Atlantic seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia, and Rissa tridactyla) and cyclone locations. We then explored the energetic consequences of different cyclonic conditions using a mechanistic bioenergetics model7 and tested the hypothesis that cyclones dramatically increase seabird energy requirements. We demonstrated that cyclones of high intensity impacted birds from all studied species and breeding colonies during winter but especially those aggregating in the Labrador Sea, the Davis Strait, the surroundings of Iceland, and the Barents Sea. Our broad-scale analyses suggested that cyclonic conditions do not increase seabird energy requirements, implying that they die because of the unavailability of their prey and/or their inability to feed during cyclones. Our study provides essential information on seabird cyclone exposure in a context of marked cyclone regime changes due to global warming.8
•Five key North Atlantic seabird species are exposed to winter cyclones•High exposure is in the Labrador Sea, the Davis Strait, the Barents Sea, and off Iceland•Seabird energy requirements do not seem to increase under cyclonic conditions•Seabird mortality during high-intensity cyclones is likely caused by starvation
Using tracking data for >1,500 migration seabirds from five key North Atlantic species, cyclone locations, and bioenergetics modeling, Clairbaux et al. demonstrate that high-intensity winter cyclones impact birds from all studied species and breeding colonies and suggest that cyclonic conditions starve seabirds by preventing them from feeding.
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Aberrant colouration in birds is relatively common but melanism occurs infrequently. We report an observation of a melanistic Razorbill Alca torda attending the nesting colony at Machias Seal Island, ...Bay of Fundy in 2022 and 2023. This is the third reported occurrence of a melanistic Razorbill and the first in over 100 years.
Measuring restoration outcomes is essential, but challenging and expensive, particularly on remote islands. Acoustic recording increases the scale of monitoring inexpensively; however, extracting ...biological information from large volumes of recordings remains challenging. Soundscape approaches, characterizing communities using acoustic indices, rapidly analyze large acoustic datasets and can be used to compare restoration sites against reference conditions. We tested this approach to measure nocturnal seabird recovery following invasive predator removal in the Aleutian Islands. We used recordings of nocturnal seabird soundscapes from six islands with varied histories of predators, from never invaded (one island) to 9–34 years post‐predator removal (four islands) and currently invaded (one island). We calculated 10 indices of acoustic intensity and complexity, and two pairwise indices of acoustic differences. Three indices reflected patterns of seabird recovery. Acoustic richness (measuring temporal entropy and amplitude) increased with time since predator removal and presence of historical predator refugia (r2 = 0.44). These factors and moonlight accounted for 30% of variation in cumulative spectral difference from the reference island. Over 10% of acoustic richness and temporal entropy was explained by Leach's Storm‐petrel (Oceanodroma leucorhoa) calls. However, indices characterized the soundscape of rat‐invaded Kiska Island like a never invaded island, likely due to high abiotic noise and few seabird calls. Soundscape indices have potential to monitor outcomes of seabird restoration quickly and cheaply, if confounding factors are considered and controlled in experimental design. We suggest soundscape indices become part of the expanding acoustic monitoring toolbox to cost‐effectively measure restoration outcomes at scale and in remote areas.
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Populations of scoter and loon species that winter in the Atlantic are understudied in North America, but coastal observatories may provide the data required to fill some of the knowledge gaps. The ...migration of scoters and loons has been monitored at the Point Lepreau Bird Observatory (PLBO) in the Bay of Fundy every spring since 1996, but little peer-reviewed research based on the resultant database has been published. Using data collected over 18 years at the Bay of Fundy (2000–2017), our objectives were to (1) determine the most accurate method of modeling hourly migration rates for Surf (Melanitta perspicillata), White-winged (M. deglandi), and Black (M. americana) scoters, and Red-throated (Gavia stellata) and Common (G. immer) loons, and (2) assess trends in hourly migration rates for our five focal species to determine if the numbers of migrants passing PLBO have changed over time. We calculated hourly migration rates for each of our five focal species and evaluated drivers (i. e., timing and environmental conditions) of migration and annual trends using zero-inflated generalized linear mixed models (GLMMs). We found that drivers of migration differed among species. Specifically, hourly migration rates decreased with increasing tide height for all species except Red-throated Loons. In addition, hourly migration rates increased with increasing wind vector (i. e., a tailwind) for the three scoter species, but decreased with increasing wind vector for the two loon species. Scoter migration rates peaked daily between 11:00 and 13:00 UTC, but we found no daily peak for either loon species. Peak hourly migration rates of Black and Surf scoters occurred from 12 to 26 April, but migration rates of White-winged Scoters and both loon species continued to increase throughout our migration-monitoring window. Finally, we found no changes in hourly migration rates over time for any of our focal species, suggesting no changes in abundance over the 18 years of data collection. Our study reveals the importance and utility of long-term, coastal observation stations, and we recommend their continued funding and use as valuable sources of monitoring data.
Las poblaciones de especies de negrones y colimbos que pasan el invierno en el Atlántico están poco estudiadas en América del Norte, pero los observatorios costeros pueden proporcionar los datos necesarios para llenar algunos de los vacíos de conocimiento. La migración de negrones y colimbos ha sido monitoreada en el Observatorio de Aves Point Lepreau (PLBO) en la Bahía de Fundy cada primavera desde 1996, pero se han publicado pocos estudias arbitrados por pares basados en la base de datos resultante. Utilizando los datos recopilados durante 18 años en la Bahía de Fundy (2000–2017), nuestros objetivos fueron (1) determinar el método más preciso para modelar las tasas de migración por hora para el Negrón costero (Melanitta perspicillata), el aliblanco (M. deglandi), y el americano (M. americana), y el Colimbo chico (Gavia stellata) y grande (G. immer), y (2) evalúan las tendencias en las tasas de migración por hora para nuestras cinco especies focales para determinar si el número de migrantes que pasan PLBO han cambiado con el tiempo. Calculamos las tasas de migración por hora para cada una de nuestras cinco especies focales y evaluamos los factores impulsores (es decir, el tiempo y las condiciones ambientales) de la migración y las tendencias anuales utilizando modelos mixtos lineales generalizados inflados a cero (GLMM). Encontramos que los impulsores de la migración diferen entre las especies. Específicamente, las tasas de migración por hora disminuyeron con el aumento de la altura de la marea para todas las especies, excepto para el Colimbo chico. Además, las tasas de migración por hora aumentaron al aumentar el vector de viento (es decir, un viento de cola) para las tres especies de negrones, pero disminuyeron al aumentar el vector de viento para las dos especies de colimbos. Las tasas de migración de negrones alcanzaron su punto máximo diariamente entre las 11:00 y las 13:00 UTC, pero no encontramos un pico diario para ninguna de las especies de colimbos. Las tasas pico de migración por hora del Negrón americano y costero ocurrieron del 12 al 26 de abril, pero las tasas de migración del Negrón aliblanco y ambas especies de colimbos continuaron aumentando a lo largo de nuestra ventana de monitoreo de la migración. Finalmente, no encontramos cambios en las tasas de migración por hora a lo largo del tiempo para ninguna de nuestras especies focales, lo que sugiere que no hubo cambios en la abundancia durante los 18 años de recopilación de datos. Nuestro estudio revela la importancia y utilidad de las estaciones de observación costera a largo plazo, y recomendamos su financiamiento continuo y su uso como valiosas fuentes de datos de monitoreo.
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Timing of breeding, an important driver of fitness in many populations, is widely studied in the context of global change, yet despite considerable efforts to identify environmental drivers of ...seabird nesting phenology, for most populations we lack evidence of strong drivers. Here we adopt an alternative approach, examining the degree to which different populations positively covary in their annual phenology to infer whether phenological responses to environmental drivers are likely to be (a) shared across species at a range of spatial scales, (b) shared across populations of a species or (c) idiosyncratic to populations.
We combined 51 long‐term datasets on breeding phenology spanning 50 years from nine seabird species across 29 North Atlantic sites and examined the extent to which different populations share early versus late breeding seasons depending on a hierarchy of spatial scales comprising breeding site, small‐scale region, large‐scale region and the whole North Atlantic.
In about a third of cases, we found laying dates of populations of different species sharing the same breeding site or small‐scale breeding region were positively correlated, which is consistent with the hypothesis that they share phenological responses to the same environmental conditions. In comparison, we found no evidence for positive phenological covariation among populations across species aggregated at larger spatial scales.
In general, we found little evidence for positive phenological covariation between populations of a single species, and in many instances the inter‐year variation specific to a population was substantial, consistent with each population responding idiosyncratically to local environmental conditions. Black‐legged kittiwake Rissa tridactyla was the exception, with populations exhibiting positive covariation in laying dates that decayed with the distance between breeding sites, suggesting that populations may be responding to a similar driver.
Our approach sheds light on the potential factors that may drive phenology in our study species, thus furthering our understanding of the scales at which different seabirds interact with interannual variation in their environment. We also identify additional systems and phenological questions to which our inferential approach could be applied.
Presenting a method for identifying populations that show positive covariance in annual phenology. The authors apply this to the breeding times of 51 North Atlantic seabird populations. While they find some evidence for spatial and taxonomic groupings that show positive phenological covariance, much of the annual variation is idiosyncratic to populations.
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Seabird colony attendance during their breeding seasons is driven by reproductive obligations of incubation and chick rearing, resulting in relatively predictable attendance patterns near breeding ...sites. Less is understood about patterns and function of activity ashore at colony sites outside the breeding season. We attempted to quantify year-round activity of crevice-nesting Crested Auklets (Aethia cristatella) at Gareloi Island, Alaska, a site with some of their largest colonies. In June and July 2013 and 2014, 94 Crested Auklets (92 adults and 2 subadults) were fitted with uniquely coded 1.0 g VHF radio-tags (0.6% of body mass) at 2 inland study plots in the southeast colony. Radio receiver–loggers remotely detected and recorded individuals present on the nearby colony site surface 24 h/d from date of tagging through autumn, winter, spring, and summer 2013–2015. Notably, we found Crested Auklets present in all months of the year, with half of our radio-tagged auklets (n = 47, 29 females, 10 males, 8 unknown sex) detected inland at the colony site during nonbreeding months (Sep–Mar). Visit duration for these individuals comprised about 0.4% of their total annual colony site activity; this is the first evidence of year-round Crested Auklet colony attendance that may be unique to Gareloi. Other findings included extreme individual variability and intersexual differences in colony attendance frequency, differences in attendance between breeding and nonbreeding birds, a lapse in surface activity prior to laying in May, and frequent nocturnal activity on the colony surface. Enhanced circannual patterns of Crested Auklet colony attendance at this island may relate to defense of nesting site and other social advantages, permitted by a nearby highly productive sea area with year-round foraging opportunities.
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Prebreeding, subadult seabirds have been documented prospecting or visiting multiple sites throughout the breeding season to gather information on colony reproductive success, identify suitable ...habitat, evaluate prey abundance, and locate potential partners; however, many aspects of prospector biology remain unknown. We explored prospector behaviour as a means of furthering our understanding of postnatal seabird dispersal and colony attendance using Least Auklets (Aethia pusilla (Pallas, 1811)) and Crested Auklets (Aethia cristatella (Pallas, 1769)) breeding at Gareloi Island, Alaska, in 2014 and 2015. We recorded age class, length of time spent on the colony, and behaviour for individuals attending a study plot over the course of two breeding seasons. Although prospectors typically spent more time on the colony surface than adults, prospectors rarely socialized with conspecifics during their visits to the colony, possibly due to the absence of a citrus-like feather odour used in olfactory communication. Additionally, we found substantial differences between observed and predicted data between years, demonstrating that other factors (likely prey abundance or quality) influenced behaviour in 2015. Our results suggest that the collective knowledge of seabird prospecting behaviour is not necessarily transferable between taxa and there may be a range of strategies employed by prospectors when assessing colonies.
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In the eastern North Atlantic, declines in the volume of Atlantic Puffin (Fratercula arctica (Linnaeus, 1758)) eggs have been associated with shifts in the marine ecosystem, such as changes in the ...abundance of forage fishes and increasing sea-surface temperatures. In the western North Atlantic, where similar shifts in oceanographic conditions and changes in the abundance of forage fishes have presumably occurred, trends in the volume of Atlantic Puffin eggs remain unknown. In this study, we investigate Atlantic Puffin egg volume in the western North Atlantic. We compiled 140 years (1877–2016) of egg volume measurements (n = 1805) and used general additive mixed-effects models to investigate temporal trends and regional variation. Our findings indicate that Atlantic Puffin egg volume differs regionally but has remained unchanged temporally in the western North Atlantic since at least the 1980s.
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