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Charlène Gémard, Thierry Aubin, Eliette L. Reboud, Francesco Bonadonna. (2021). Call rate, fundamental frequency, and syntax determine male-call attractiveness in blue petrels Halobaena caerulea (Vol. 75).
Abstract: In blue petrels (Halobaena caerulea), females are supposed to be particularly choosy and mate choice can take a couple of years. In these lifelong monogamous seabirds, choosing a good mate is crucial and has a strong influence on their fitness. Due to their nocturnal habits, the absence of sexual dimorphism, and the physical barrier between males calling from their burrow and females flying above the colony, vocal signals seem to be one of the main channels for males to communicate with potential mates. In a previous study, we investigated whether acoustic parameters of male calls carry information about morphological characteristics that might be indicators of males’ qualities. Here, we experimentally test whether these acoustic parameters linked to male characteristics are actually attractive to females. To do so, we played back modified calls of males to females in a colony of blue petrels of the Kerguelen archipelago. We found that flying females were more attracted by high-pitched calls, and by calls broadcasted at a high call rate. Previous studies showed a relationship between pitch and bill depth and length. In filter-feeding birds, such as blue petrels, bill morphology influences feeding efficiency. A high call rate is an indicator of sexual motivation and makes the caller easier to locate by potential mates and predators in the hubbub of the colony. We thus hypothesized that producing frequent high-pitched calls appeared to be preferable for a conspicuous sexual signaling although it may increase predation risks.
Programme: 354
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Samara Danel, Jules Chiffard-Carricaburu, Francesco Bonadonna, Anna P. Nesterova. (2021). Exclusion in the field: wild brown skuas find hidden food in the absence of visual information (Vol. 24).
Abstract: Inferential reasoning by exclusion allows responding adaptively to various environmental stimuli when confronted with inconsistent or partial information. In the experimental context, this mechanism involves selecting correctly between an empty option and a potentially rewarded one. Recently, the increasing reports of this capacity in phylogenetically distant species have led to the assumption that reasoning by exclusion is the result of convergent evolution. Within one largely unstudied avian order, i.e. the Charadriiformes, brown skuas (Catharacta antarctica ssp lonnbergi) are highly flexible and opportunistic predators. Behavioural flexibility, along with specific aspects of skuas’ feeding ecology, may act as influencing factors in their ability to show exclusion performance. Our study aims to test whether skuas are able to choose by exclusion in a visual two-way object-choice task. Twenty-six wild birds were presented with two opaque cups, one covering a food reward. Three conditions were used: ‘full information’ (showing the content of both cups), ‘exclusion’ (showing the content of the empty cup), and ‘control’ (not showing any content). Skuas preferentially selected the rewarded cup in the full information and exclusion condition. The use of olfactory cues was excluded by results in the control condition. Our study opens new field investigations for testing further the cognition of this predatory seabird.
Programme: 354
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Samara Danel, Timothée Zidat, Annick Lucas, Dora Biro, Francesco Bonadonna. (2021). First description of nest-decoration behaviour in a wild sub-Antarctic shorebird (Vol. 188).
Abstract: A wide range of animal species accumulate objects in, on, and/or around structures they build. Sometimes, these accumulations serve specific functions (e.g. structural or isolating features) or are purely incidental, while in other cases the materials are deliberately displayed to serve signalling purposes (extended phenotype signals). In this pilot study, we employed systematic in situ observations and camera trapping to describe for the first time that both partners of a territorial shorebird, the black-faced sheathbill (Chionis minor ssp minor) collect, carry, and arrange colourful marine shells and dry twigs within and around their nest cavity. Our observations expand the taxonomic breadth of avian extended phenotype signals, by showing that at least one species within a largely understudied group i.e., Charadriiformes, exhibits nest-decoration behaviour. Multiple manipulative experiments are needed to explore further the signalling function of these decorations, which opens new exciting avenues for animal communication and cognition research.
Keywords: Animal communication Extended phenotype Nest decoration Non-bodily ornament Signal
Programme: 354
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Charlène Gémard, Víctor Planas-Bielsa, Francesco Bonadonna, Thierry Aubin. (2021). Contextual variations in calls of two nonoscine birds: the blue petrel Halobaena caerulea and the Antarctic prion Pachyptila desolata (Vol. 32).
Abstract: Bird vocalizations are critical cues in social interactions as they convey temporary information varying with the social context, for example, the signaler motivation when facing a rival or a potential mate. To date, literature mainly focused on learning birds. Burrowing petrels (Procellariidae) are nonlearning birds with a limited vocal repertoire. Bachelor males communicate with conspecifics with a single call emitted in three situations: in the absence of a certain auditory (spontaneous calls), toward females (female-directed calls), and toward males (male-directed calls). We first hypothesized that, although the call structure is preserved, temporal and spectral parameters vary between the three call types of bachelor males, translating different motivations (Motivation Hypothesis). To go further, we hypothesized that acoustic variations in male-directed calls indicate the signaler’s aggressive motivation and, therefore, the variations are similar whether calls are produced by breeder or bachelor males (Breeding Status Hypothesis). We tested the two hypotheses performing field playback experiments on two petrel species: the blue petrel (Halobaena caerulea) and the Antarctic prion (Pachyptila desolata). Despite the obvious call stereotypy, we observed temporal variations and frequency shifts when males react to a female or a male, which may translate the sexual or aggressive motivation of the signaler. Furthermore, the similarity of variations in male-directed calls of both breeder and bachelor males suggests the aggressive motivation. So far, vocal plasticity in nonlearning birds has been greatly underestimated. Here, we highlighted the expression of different motivations through vocal variations and the ability to produce frequency variations in species with genetically coded vocalizations.
Programme: 354
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María José Frugone, Theresa L. Cole, María Eugenia López, Gemma Clucas, Pável Matos-Maraví, Nicolás A. Lois, Pierre Pistorius, Francesco Bonadonna, Phil Trathan, Andrea Polanowski, Barbara Wienecke, Andrea Raya-Rey, Klemens Pütz, Antje Steinfurth, Ke Bi, Cynthia Y. Wang-Claypool, Jonathan M. Waters, Rauri C. K. Bowie, Elie Poulin, Juliana A. Vianna. (2021). Taxonomy based on limited genomic markers may underestimate species diversity of rockhopper penguins and threaten their conservation (Vol. 27).
Abstract: Aim Delimiting recently diverged species is challenging. During speciation, genetic differentiation may be distributed unevenly across the genome, as different genomic regions can be subject to different selective pressures and evolutionary histories. Reliance on limited numbers of genetic markers that may be underpowered can make species delimitation even more challenging, potentially resulting in taxonomic inconsistencies. Rockhopper penguins of the genus Eudyptes comprise three broadly recognized taxa: northern (E. moseleyi), southern (E. chrysocome) and eastern rockhopper (E. filholi). Their taxonomic status has been controversial for decades, with researchers disagreeing about whether E. chrysocome and E. filholi are distinct species or conspecific. Our goal is to evaluate genome-wide patterns of divergence to evaluate genetic differentiation and species delimitation in rockhopper penguins, and to assess which mechanisms may underlie previous discordance among nuclear versus mitochondrial analyses. Location Sub-Antarctic and temperate coastal regions of the Southern Hemisphere. Methods We generated reduced-representation genomic libraries using double digest restriction-site associated DNA (ddRAD) sequencing to evaluate genetic differentiation, contemporary migration rates and admixture among colonies of rockhopper penguins. Results The extent of genetic differentiation among the three taxa was consistently higher than population-level genetic differentiation found within these and other penguin species. There was no evidence of admixture among the three taxa, suggesting the absence of ongoing gene flow among them. Species delimitation analyses based on molecular data, along with other lines of evidence, provide strong support for the taxonomic distinction of three species of rockhopper penguins. Main conclusions Our results provide strong support for the existence of three distinct species of rockhopper penguins. The recognition of this taxonomic diversity is crucial for the management and conservation of this widely distributed species group. This study illustrates that widespread dispersive seabird lineages lacking obvious morphological differences may nevertheless have complex evolutionary histories and comprise cryptic species diversity.
Keywords: Eudyptes genomics rockhopper penguins species delimitation
Programme: 354
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C. Albert, V. S. Bråthen, S. Descamps, T. Anker-Nilssen, A. Cherenkov, S. Christensen-Dalsgaard, J. Danielsen, K. E. Erikstad, M. Gavrilo, S. A. Hanssen, H. H. Helgason, J. E. Jónsson, Y. Kolbeinsson, Y. Krasnov, M. Langset, E. Lorentzen, B. Olsen, T. K. Reiertsen, H. Strøm, G. H. Systad, G. Tertitski, P. M. Thompson, T. L. Thórarinsson, P. Bustamante, B. Moe, J. Fort. (2021). Inter-annual variation in winter distribution affects individual seabird contamination with mercury (Vol. 676).
Abstract: Migratory seabirds are exposed to various pollutants throughout their annual cycle. Among them, mercury (Hg) is of particular concern given its large impact on animal health. Recent studies suggest that winter is a critical period for seabirds when contamination by Hg can be higher than at other times of year. However, individuals within and between species can have different migration strategies and winter distributions that could affect their exposure. Here, we combined multi-year individual tracking data and Hg measurements from 6 Arctic seabird species. We investigated whether inter-annual variations in individual winter contamination with Hg was related to seabird fidelity to a wintering site over years. First, our results show that Hg concentrations above the toxicity threshold (i.e. 5 µg g-1 dry weight in feathers) were observed in variable proportions according to species (from 2% of northern fulmars to 37% of Brünnich’s guillemots). Second, individuals with high fidelity to a wintering ground had more similar Hg concentrations among years compared to individuals with low fidelity, suggesting an effect of their migratory strategy on Hg contamination. Further, we found that the directional change in wintering areas among years influenced seabird Hg contamination, highlighting an additional effect of seabirds’ winter distribution. More specifically, individuals migrating to the northwest direction of a previous wintering ground tended to be more contaminated compared to those moving to eastern directions. These results confirm spatial differences in Hg concentration throughout the North Atlantic-Arctic and an east-west gradient increase in Hg concentrations. Verifying this trend will require more large-scale ecotoxicological studies at smaller spatial resolution.
Keywords: Biologging Feathers Migration North Atlantic-Arctic Pollutant
Programme: 388
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Alice Bernard, Ana S. L. Rodrigues, Victor Cazalis, David Grémillet. (2021). Toward a global strategy for seabird tracking (Vol. 14).
Abstract: Electronic tracking technologies revolutionized wildlife ecology, notably for studying the movements of elusive species such as seabirds. Those advances are key to seabird conservation, for example in guiding the design of marine protected areas for this highly threatened group. Tracking data are also boosting scientific understanding of marine ecosystem dynamics in the context of global change. To optimize future tracking efforts, we performed a global assessment of seabird tracking data. We identified and mined 689 seabird tracking studies, reporting on > 28,000 individuals of 216 species from 17 families over the last four decades. We found substantial knowledge gaps, reflecting a historical neglect of tropical seabird ecology, with biases toward species that are heavier, oceanic, and from high-latitude regions. Conservation status had little influence on seabird tracking propensity. We identified 54 threatened species for which we did not find published tracking records, and 19 with very little data. Additionally, much of the existing tracking data are not yet available to other researchers and decision-makers in online databases. We highlight priority species and regions for future tracking efforts. More broadly, we provide guidance toward an ethical, rational, and efficient global tracking program for seabirds, as a contribution to their conservation.
Keywords: biogeography biologging biotelemetry ecological monitoring marine conservation oceanography spatial planning threatened species
Programme: 388
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Marina Renedo, David Amouroux, Céline Albert, Sylvain Bérail, Vegard S. Bråthen, Maria Gavrilo, David Grémillet, Hálfdán H. Helgason, Dariusz Jakubas, Anders Mosbech, Hallvard Strøm, Emmanuel Tessier, Katarzyna Wojczulanis-Jakubas, Paco Bustamante, Jérôme Fort. (2021). Contrasting Spatial and Seasonal Trends of Methylmercury Exposure Pathways of Arctic Seabirds: Combination of Large-Scale Tracking and Stable Isotopic Approaches (Vol. 54).
Abstract: Despite the limited direct anthropogenic mercury (Hg) inputs in the circumpolar Arctic, elevated concentrations of methylmercury (MeHg) are accumulated in Arctic marine biota. However, the MeHg production and bioaccumulation pathways in these ecosystems have not been completely unraveled. We measured Hg concentrations and stable isotope ratios of Hg, carbon, and nitrogen in the feathers and blood of geolocator-tracked little auk Alle alle from five Arctic breeding colonies. The wide-range spatial mobility and tissue-specific Hg integration times of this planktivorous seabird allowed the exploration of their spatial (wintering quarters/breeding grounds) and seasonal (nonbreeding/breeding periods) MeHg exposures. An east-to-west increase of head feather Hg concentrations (1.74–3.48 μg·g–1) was accompanied by significant spatial trends of Hg isotope (particularly Δ199Hg: 0.96–1.13‰) and carbon isotope (δ13C: −20.6 to −19.4‰) ratios. These trends suggest a distinct mixing/proportion of MeHg sources between western North Atlantic and eastern Arctic regions. Higher Δ199Hg values (+0.4‰) in northern colonies indicate an accumulation of more photochemically impacted MeHg, supporting shallow MeHg production and bioaccumulation in high Arctic waters. The combination of seabird tissue isotopic analysis and spatial tracking helps in tracing the MeHg sources at various spatio-temporal scales.
Programme: 388
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Benjamin Merkel, Sébastien Descamps, Nigel G. Yoccoz, David Grémillet, Francis Daunt, Kjell E. Erikstad, Aleksey V. Ezhov, Mike P. Harris, Maria Gavrilo, Svein-Håkon Lorentsen, Tone K. Reiertsen, Harald Steen, Geir H. Systad, Þorkell Lindberg Þórarinsson, Sarah Wanless, Hallvard Strøm. (2021). Individual migration strategy fidelity but no habitat specialization in two congeneric seabirds (Vol. 48).
Abstract: Aim In migratory species, individuals often use fixed and individual-specific migration strategies, which we term individual migration strategy fidelity (IMSF). Our goal was to test if guillemots have flexible or fixed individual migration strategies (i.e. IMSF), if this behaviour is consistent across large parts of the genus’ range and if they were philopatric to geographical sites or a habitat feature. Location North Atlantic. Taxon Uria spp. Methods We quantified consistent individual differences in inter-annual spatial distribution and habitat occupied throughout the non-breeding period using a large geolocator tracking dataset of 729 adult seabirds breeding at 13 colonies across the Northeast Atlantic and repeatedly tracked up to 7 years over a 9-year period. Additionally, we used a similarity index to calculate relative fidelity to either geographical sites or habitats and linear mixed-effects models to assess persistence of spatial site fidelity over multiple years. Results Both guillemot species exhibited IMSF across a large part of the genus’ range which persisted over multiple years. Individuals of both species and almost all colonies showed fidelity to geographical sites and not to specific habitats. Main conclusions Guillemots show IMSF that is best explained by site familiarity (fidelity to specific sites) rather than habitat specialization (fidelity to specific habitats). In the context of rapidly changing environments, favourable habitats may permanently shift locations and hence species displaying IMSF driven by site familiarity—such as the genus Uria—may not be able to adjust their migration strategies sufficiently fast to sustain individual fitness and ensure population persistence.
Keywords: guillemots light-level geolocation murres Uria aalge Uria lomvia
Programme: 388
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Céline Albert, Hálfdán Helgi Helgason, Maud Brault-Favrou, Gregory J. Robertson, Sébastien Descamps, Françoise Amélineau, Jóhannis Danielsen, Rune Dietz, Kyle Elliott, Kjell Einar Erikstad, Igor Eulaers, Alexey Ezhov, Michelle G. Fitzsimmons, Maria Gavrilo, Elena Golubova, David Grémillet, Scott Hatch, Nicholas P. Huffeldt, Dariusz Jakubas, Alexander Kitaysky, Yann Kolbeinsson, Yuri Krasnov, Svein-Håkon Lorentsen, Erlend Lorentzen, Mark L. Mallory, Benjamin Merkel, Flemming Ravn Merkel, William Montevecchi, Anders Mosbech, Bergur Olsen, Rachael A. Orben, Allison Patterson, Jennifer Provencher, Christine Plumejeaud, Isabeau Pratte, Tone Kristin Reiertsen, Heather Renner, Nora Rojek, Marc Romano, Hallvard Strøm, Geir Helge Systad, Akinori Takahashi, Jean-Baptiste Thiebot, Thorkell Lindberg Thórarinsson, Alexis P. Will, Katarzyna Wojczulanis-Jakubas, Paco Bustamante, Jérôme Fort. (2021). Seasonal variation of mercury contamination in Arctic seabirds: A pan-Arctic assessment (Vol. 750).
Abstract: Mercury (Hg) is a natural trace element found in high concentrations in top predators, including Arctic seabirds. Most current knowledge about Hg concentrations in Arctic seabirds relates to exposure during the summer breeding period when researchers can easily access seabirds at colonies. However, the few studies focused on winter have shown higher Hg concentrations during the non-breeding period than breeding period in several tissues. Hence, improving knowledge about Hg exposure during the non-breeding period is crucial to understanding the threats and risks encountered by these species year-round. We used feathers of nine migratory alcid species occurring at high latitudes to study bird Hg exposure during both the breeding and non-breeding periods. Overall, Hg concentrations during the non-breeding period were ~3 times higher than during the breeding period. In addition, spatial differences were apparent within and between the Atlantic and Pacific regions. While Hg concentrations during the non-breeding period were ~9 times and ~3 times higher than during the breeding period for the West and East Atlantic respectively, Hg concentrations in the Pacific during the non-breeding period were only ~1.7 times higher than during the breeding period. In addition, individual Hg concentrations during the non-breeding period for most of the seabird colonies were above 5 μg g−1 dry weight (dw), which is considered to be the threshold at which deleterious effects are observed, suggesting that some breeding populations might be vulnerable to non-breeding Hg exposure. Since wintering area locations, and migration routes may influence seasonal Hg concentrations, it is crucial to improve our knowledge about spatial ecotoxicology to fully understand the risks associated with Hg contamination in Arctic seabirds.
Keywords: Feathers Metal Polar Seasonal variation Top predators
Programme: 388
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