Explore the vast range of titles available.

The processes that drive the ontogeny of migratory strategies in long‐lived animals with slow maturation remain enigmatic. While some short‐lived migrants are known or believed to repeat the same migratory patterns throughout their lives, little is known on the time required for immature long‐lived migrants to progressively acquire adult‐like migratory behaviours, or which aspects take longer to refine during the maturation process. Here, we studied the ontogeny of long‐distance migratory strategies and related patterns of spatial distribution in a long‐lived seabird species during the annual cycle. To do so, we deployed light‐level geolocators on 4‐ to 9‐year‐old immature Cory's shearwaters (Calonectris borealis) and on breeding adults. We revealed that migratory timings and destinations of young shearwaters progressively changed with age. The effect of ageing was remarkably evident on spring migratory performance and phenology. Birds gradually shortened the duration of the non‐breeding period by advancing departure date and reducing travelling time, which resulted in a sequential arrival at the colony of the various age contingents. Ageing immatures gradually changed from a more exploratory strategy to a more conservative way of exploiting resources, reducing both their year‐round spatial spread across oceanic domains and the total distance travelled. Immatures always performed a trans‐equatorial migration to the Southern Hemisphere, contrasting with 17% of the adults which remained in the North Atlantic year‐round. Finally, during the breeding season immatures were widely dispersed through the North Atlantic reducing their overlap with breeding adults. Our long‐term study provides empirical support to the hypothesis that in long‐lived species, the refinement of migratory behaviour and year‐round spatial distribution is a progressive process mediated by age and experience, where life stage constraints and competition for resources may also play a role. The emerging pattern suggests that for some avian taxa, the ontogeny of migratory strategy is a prolonged, complex and dynamic process. The ontogeny of migratory strategies in long‐lived animals with slow maturation remains enigmatic. This long‐term study provides empirical support to the hypothesis that in long‐lived species as Cory's shearwater, the refinement of migratory behaviour and year‐round spatial distribution is a progressive process mediated by age and experience where life stage constraints and competition for resources may also play a role.

The little auk is the most numerous seabird in the North Atlantic and its most important breeding area is the eastern shores of the North Water polynya. Here, a population of an estimated 33 million pairs breeds in huge colonies and significantly shapes the ecosystem. Archaeological remains in the colonies document that the little auk has been harvested over millennia. Anthropological research discloses how the little auk has a role both as social engineer and as a significant resource for the Inughuit today. The hunting can be practiced without costly equipment, and has no gender and age discrimination in contrast to the dominant hunt for marine mammals. Little auks are ecological engineers in the sense that they transport vast amounts of nutrients from sea to land, where the nutrients are deposited as guano. Here, the fertilized vegetation provides important foraging opportunities for hares, geese, fox, reindeer, and the introduced muskox. We estimate that the relative muskox density is ten times higher within 1 km of little auk fertilized vegetation hotspots.

In this article we provide pipelines for acquiring and processing Sea-Bird Scientific Spectral Absorption and Attenuation Sensor (ac-s) data through a high-level Python package. The raw streamed and converted instrument output is complex and requires several post-processing steps rooted in optical theory and empirical methods to create base products for algorithms that approximate biogeochemical properties and appeal to a broader oceanographic community. Because datasets from the ac-s are becoming more available in public archives and in real time from large oceanographic infrastructure programs, it is important to establish uncomplicated software packages and interfaces that support the implementation of best practices and the distribution of findable, accessible, interoperable, and reusable (FAIR) data. acspype provides means to perform both instrument-intrinsic and human-in-the-loop corrections with flexibility and clear provenance following well-established manufacturer and research community guidelines. Core functions are provided that allow for the acquisition of real-time data and for post-processing archived datasets. As best practices continue to evolve, acspype would benefit from the addition of time-lag correction functions, methods for assessing instrument drift, and improved uncertainty estimation procedures.

The identification of geographic areas where the densities of animals are highest across their annual cycles is a crucial step in conservation planning. In marine environments, however, it can be particularly difficult to map the distribution of species, and the methods used are usually biased towards adults, neglecting the distribution of other life‐history stages even though they can represent a substantial proportion of the total population. Here we develop a methodological framework for estimating population‐level density distributions of seabirds, integrating tracking data across the main life‐history stages (adult breeders and non‐breeders, juveniles and immatures). We incorporate demographic information (adult and juvenile/immature survival, breeding frequency and success, age at first breeding) and phenological data (average timing of breeding and migration) to weight distribution maps according to the proportion of the population represented by each life‐history stage. We demonstrate the utility of this framework by applying it to 22 species of albatrosses and petrels that are of conservation concern due to interactions with fisheries. Because juveniles, immatures and non‐breeding adults account for 47%–81% of all individuals of the populations analysed, ignoring the distributions of birds in these stages leads to biased estimates of overlap with threats, and may misdirect management and conservation efforts. Population‐level distribution maps using only adult distributions underestimated exposure to longline fishing effort by 18%–42%, compared with overlap scores based on data from all life‐history stages. Synthesis and applications. Our framework synthesizes and improves on previous approaches to estimate seabird densities at sea, is applicable for data‐poor situations, and provides a standard and repeatable method that can be easily updated as new tracking and demographic data become available. We provide scripts in the R language and a Shiny app to facilitate future applications of our approach. We recommend that where sufficient tracking data are available, this framework be used to assess overlap of seabirds with at‐sea threats such as overharvesting, fisheries bycatch, shipping, offshore industry and pollutants. Based on such an analysis, conservation interventions could be directed towards areas where they have the greatest impact on populations.

The Arctic is currently experiencing the most rapid warming on Earth. Arctic species communities are expected to be restructured with species adapted to warmer conditions spreading poleward and, if already present, becoming more abundant. We tested this prediction using long-term monitoring data (2009–2018) from nine of the most common seabird species breeding in the High Arctic Svalbard archipelago. This region is characterized by rapidly warming ocean temperatures, declining sea-ice concentrations and an increasing influence of Atlantic waters. Concurrent with these environmental changes, we found a shift in the Svalbard seabird community, with an increase in abundance of boreal species (defined here as species breeding commonly in temperate environments) and a decline in Arctic species (species breeding predominantly in the Arctic). Combined with previous observations from lower trophic levels, our results confirmed that part of the Arctic fauna is moving from an arctic to a boreal (or north temperate) state, a process referred to as a “borealization.” Spatial variations exist among colonies for some species, indicating that local conditions may affect the trajectories of specific populations and potentially counterbalance the consequences of large-scale climate warming.

Pollutant biomonitoring demands analytical methods to cover a wide range of target compounds, work with minimal sample amounts, and apply least invasive and reproducible sampling procedures. We developed a method to analyse 68 bioaccumulative organic pollutants in three seabird matrices: plasma, liver, and stomach oil, representing different exposure phases. Extraction efficiency was assessed based on recoveries of spiked surrogate samples, then the method was applied to environmental samples collected from Scopoli’s shearwater ( Calonectris diomedea ). Extraction was performed in an ultrasonic bath, purification with Florisil cartridges (5 g, 20 mL), and analysis by GC–Orbitrap–MS. Quality controls at 5 ng yielded satisfactory recoveries (80–120%) although signal intensification was found for some compounds. The method permitted the detection of 28 targeted pollutants in the environmental samples. The mean sum of organic pollutants was 4.25 ± 4.83 ng/g in plasma, 1634 ± 2990 ng/g in liver, and 233 ± 111 ng/g in stomach oil (all wet weight). Pollutant profiles varied among the matrices, although 4,4′-DDE was the dominant compound overall. This method is useful for pollutant biomonitoring in seabirds and discusses the interest of analysing different matrices.

The Arctic is undergoing rapid declines in sea ice and changes in Arctic ecosystems. The diet of one of the Arctic’s most abundant seabirds, the black-legged kittiwake ( Rissa tridactyla), has been used as an indicator of ecosystem changes in the European Arctic, yet little is known about their diet in the Canadian Arctic. We quantified the stomach contents of kittiwakes near Qikiqtarjuaq and Mittimatalik (Pond Inlet), Nunavut, in the Canadian Arctic, and assessed if stable carbon (δ 13 C) and nitrogen (δ 15 N) isotopes in livers differed from that of the dominant prey in their stomachs. Based on stomach contents, prey did not significantly differ between regions, where the dominant prey was Arctic cod ( Boreogadus saida). However, after accounting for dietary discrimination, δ 13 C and δ 15 N values of kittiwake liver were at a lower trophic level than that of Arctic cod muscle. Thus, while kittiwakes do readily consume Arctic cod, stomach content analysis may underestimate soft tissue prey in their diet, such as invertebrates. Future research should include regurgitate and faecal samples to better understand kittiwake diet in the Canadian Arctic. Nevertheless, as climate change impacts continue to increase, this study provides important benchmark information for monitoring changes in these Arctic-breeding seabirds.