Rissa Tridactyla Research Articles

North Atlantic winter cyclones starve seabirds

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.

Species and spatial variation in the effects of sea ice on Arctic seabird populations

AbstractAimThe Arctic is warming rapidly, and sea ice is disappearing. This is expected to have profound effects on Arctic wildlife. However, empirical evidence that this decline in sea ice is associated with a decline in Arctic wildlife populations is lacking.LocationSvalbard Archipelago.MethodsUsing long‐term time series data (1988–2018) from two fjords in West Spitsbergen (Svalbard), we tested whether or not sea ice concentration was associated with the population size of two of the most common Arctic seabirds, the Brünnich's guillemot (Uria lomvia) and black‐legged kittiwake (Rissa tridactyla).ResultsWe found that the size of guillemot and kittiwake colonies has declined on Svalbard from the mid‐1990s onwards, though the shapes of these trajectories were not linear and kittiwake colony size has stabilized or even increased in recent years. sea ice concentration in West Spitsbergen also declined during the study period. Independent of these long‐term trends, sea ice concentration was positively and significantly associated with seabird colony size with a 2‐year lag, though variations in sea ice explained only a small proportion of the changes in colony size. One likely mechanism linking sea ice and seabird population size involves changes in the food chain, with poor sea ice conditions in a given year leading to low food availability 2 years later. This would affect breeding probability and hence colony size for kittiwakes and guillemots. This relationship between sea ice and colony size was the same in both fjords for guillemots. In the case of kittiwakes, it was not apparent in the fjord where productive glacier fronts, intensely used by kittiwakes to forage, may have buffered the effects of changes in sea ice.Main conclusionsOur study provides evidence that the ongoing decline in Arctic sea ice plays a role in Arctic seabird population trajectories. However, sea ice disappearance on the breeding grounds was likely not the main driver of changes in seabird populations.

Acute impacts from Teflon harnesses used to fit biologging devices to Black-legged Kittiwakes Rissa tridactyla

ABSTRACT Biologging is a routine technique for investigating movements and behaviours of birds in ecology, needing harnesses to attach devices to birds when long-term data of high spatial resolution are required. Evaluating the impacts on individuals of those devices and their attachment methods is important to maintain both animal welfare and the validity of data. In two independent trials of harnesses on Black-legged Kittiwake Rissa tridactyla, in Norway and the UK, harnesses were constructed from Teflon ribbon and deployed on breeding adults using two different attachment methods, a leg-loop (UK; n = 3) and thoracic cross-strap harness (UK; n = 3, Norway; n = 2). The birds were later recaptured and the harness fit and bird condition inspected. We found acute impacts from the harnesses of varying extent and severity, including abrasion and small lesions where the device or harness was sitting. Generally, the thoracic harness design caused more severe impacts, but some signs of feather abrasion were also evident on leg-loop individuals. While there was an apparently larger impact of thoracic harnesses on daily mass loss between recaptures compared with untagged or leg-loop individuals, the low sample sizes denied us statistically meaningful results. Continual appraisal in biologging studies is important, especially when studying a novel combination of species and attachment methods, even if those methods have been demonstrated to be safe and effective with similar taxa. Given the degree of abrasion reported here, we would not recommend the use of thoracic harnesses for Kittiwakes. However, leg-loops may be a viable alternative if different materials or design are used, provided that the impacts can be closely monitored and reported.

Improving assessments of data‐limited populations using life‐history theory

Abstract Predicting how populations may respond to climate change and anthropogenic pressures requires detailed knowledge of demographic traits, such as survival and reproduction. However, the availability of these data varies greatly across space and taxa. Therefore, it is common practice to conduct population assessments by filling in missing values from surrogate species or other populations of the same species. Using these independent surrogate values concurrently with observed data neglects the life‐history trade‐offs that connect the different aspects of a population's demography. Consequently, this approach introduces biases that could ultimately lead to erroneous management decisions. We use a Bayesian hierarchical framework to combine fragmented multi‐population data with established life‐history theory and reconstruct population‐specific demographic data across a substantial part of a species breeding range. We apply our analysis to a long‐lived colonial species, the black‐legged kittiwake Rissa tridactyla, that is classified as globally Vulnerable and is highly threatened by increasing anthropogenic pressures, including offshore renewable energy development. We then use a projection analysis to examine how the reconstructed demographic parameters may improve population assessments, compared to models that combine observed data with independent surrogate values. Demographic parameters reconstructed using a hierarchical framework can be utilised in a range of population modelling approaches. They can also be used as reference estimates to assess whether independent surrogate values are likely to over or underestimate missing demographic parameters. We show that surrogate values from independent sources are often used to fill in missing parameters that have large potential demographic impact, and that resulting biases are driven in unpredictable directions thus precluding assessments from being consistently precautionary. Synthesis and applications. Our study dramatically increases the spatial coverage of population‐specific demographic data for black‐legged kittiwakes. The reconstructed demographic parameters presented can also be used immediately to reduce uncertainty in the consenting process for offshore wind development in the United Kingdom and Ireland. More broadly, we show that the reconstruction approach used here provides a new avenue for improving evidence‐based management and policy action for animal and plant populations with fragmented and error prone demographic data.

Mercury contamination of seabird and sea duck eggs from high Arctic Greenland

Mercury (Hg) levels in the environment have substantially increased over the past century leading to increased concentrations in many high trophic level predators, including Arctic seabirds. From the Canadian high Arctic, research on seabird eggs has documented some of the greatest concentrations of egg Hg anywhere in the Arctic. Farther east, in high Arctic Greenland, no similar data on Hg concentrations in eggs exist, making spatial comparisons unfeasible. To address this paucity of data, we collected whole eggs from Thick-billed Murre Uria lomvia (n = 11), Black-legged Kittiwake Rissa tridactyla (n = 9), and Common Eider Somateria mollissima (n = 12) in the high Arctic of northwest Greenland in the summer of 2014 and assessed their concentration of total Hg. Thick-billed Murre eggs had the highest mean total Hg concentrations (1.32 ± 0.42 mg g−1 dw) followed by kittiwakes (0.64 ± 0.19) and eiders (0.23 ± 0.10). When compared with murre and kittiwake egg samples collected in high Arctic Canada during the same time period, total Hg concentrations from northwest Greenland were higher, but not significantly. Based on what is known about lethal Hg concentrations in murre eggs, these results indicate that some murre eggs may be at risk for increased embryonic mortality and further monitoring is suggested to determine long-term trends in egg Hg concentrations.

Spying on your neighbours? Social information affects timing of breeding and stress hormone levels in a colonial seabird

A good overlap between offspring energetic requirements and availability of resources is required for successful reproduction. Accordingly, individuals from numerous species fine-tune their timing of breeding by integrating cues that predict environmental conditions during the offspring period. Besides acquiring information from their direct interaction with the environment (personal information), individuals can integrate information by observing the behaviours or performance of others (social information). The use of social information is often beneficial because the accumulated knowledge of conspecifics may represent a source of information more reliable than the intrinsically more limited personal information. However, although social information constitutes the major source of information in a wide range of contexts, studies investigating its use in the context of timing of breeding are scarce. We investigated whether black-legged kittiwakes (Rissa tridactyla) used social information to adjust the timing of egg-laying. We manipulated social information using a food-supplementation experiment, known to advance kittiwakes' reproductive phenology. We expected food-supplemented and unsupplemented pairs to delay and advance, respectively, their timing of laying when surrounded by a majority of neighbours from the opposite food-treatment. However, both unsupplemented and food-supplemented kittiwakes delayed egg-laying when surrounded by a higher proportion of neighbours from the opposite food-treatment. This result shows that kittiwakes use social information to time egg-laying, but that it is not used to match the seasonal peak of food availability. We suggest that when social and personal cues give contradictory environmental information, individuals may benefit from delaying laying to gather more information to make better decisions about investment into eggs. Further, we explored a potential proximate mechanism for the pattern we report. We show that baseline corticosterone, known to mediate reproductive decisions, was lower in unsupplemented females facing a higher proportion of food-supplemented neighbours. Altogether, our results suggest that to fine-tune their timing of laying, kittiwakes use complex decision-making processes in which social and personal information interplay.

Reactions of a colonial seabird species to controlled gunshot disturbance experiments

Gunshots are a worldwide source of anthropogenic disturbance, and knowledge about the potential effect on wildlife is central for conservation and sustainable management of affected species. This study contributes novel insight of the response behaviour and effect of gunshot disturbance on one of the most culturally important seabird species of the Arctic, the thick-billed murre (Brünnich's guillemot, Uria lomvia). We studied effects of gunshot disturbance at breeding colonies to explore the distance where effects started, the difference in the behavioural response between presumed disturbed colonies (e.g. by traffic and hunting) and largely undisturbed colonies, and among plots with varying seabird densities. We carried out two different types of controlled gunshot experiments – one measuring the distance at which murres first reacted to gunshots (flight initiation distance, ‘FID') and one measuring the proportion of murres remaining in the colony during and after repeated gunshots (20 gunshots within 78 min). FID varied from 0.5 to 5 km. The proportion of murres remaining in the plot after the repeated gunshots ranged from 0.44 to 0.8. Mainly murres not attending offspring took off when disturbed by gunshots, but occasionally also birds incubating their egg or brooding their chick took off. We found that density of seabirds (murres and black-legged kittiwakes Rissa tridactyla) at the plot area scale was the best explaining factor for FID, and to some extent also for the effect of repeated gunshots, both for disturbed and undisturbed colonies. Murres in denser colonies reacted earlier (had larger FIDs) and somewhat more strongly (higher proportions fleeing) to gunshots than murres in less densely populated colonies. FID clearly showed that the current legislation in Greenland regulating gunshots near breeding colonies is insufficient. We provide some recommendations for improved management of a popular game species under pressure.

Advection of Atlantic water masses influences seabird community foraging in a high-Arctic fjord

Hornsund is a typical high-Arctic fjord, with the usual predominance of water masses of the Arctic origin, and associated lipid-rich zooplankton, which is an important food source for many seabird species. The fjord hosts one of the largest concentrations of breeding little auks worldwide, as well as several large colonies of black-legged kittiwakes, Brünnich's guillemots and northern fulmars. However, in summer 2014, for the first time in the history of almost two-decades long, comprehensive hydrographic studies, the large-scale advection of a relatively warm and saline Atlantic Water was observed in the fjord. These changes in the properties of water masses were associated with significant inter-annual changes in seabird community numbers and composition in the fjord. The advection of Atlantic water masses to Hornsund in 2014 clearly promoted the domination of Boreal black-legged kittiwakes, while rather cold summer seasons of 2015 and 2016 were characterised by the significant proportion of the Arctic little auks. Also, the use of different foraging habitats by seabirds changed between the studied years, with the higher importance of the land-based glacier bays and non-glaciated coastline for the kittiwake in 2014. Our results suggest that with the progressing warming in the Arctic, significant changes in the numbers and structure of seabird community are expected, which in turn will influence the functioning of the high-Arctic fjordic ecosystems.

Abundance, habitat use and food consumption of seabirds in the high-Arctic fjord ecosystem

To monitor the rapid changes occurring in Arctic ecosystems and predict their direction, basic information about the current number and structure of the main components of these systems is necessary. Using boat-based surveys, we studied the numbers and distribution of seabirds foraging in Hornsund (SW Spitsbergen) during three summer seasons. The average number of seabirds foraging concurrently in the whole fjord was estimated at 28,000. Little Auks Alle alle were the most numerous, followed by Northern Fulmars Fulmarus glacialis, Brünnich’s Guillemots Uria lomvia and Black-legged Kittiwakes Rissa tridactyla. The pelagic zone was exploited by some 75% of the birds. Their density was the highest (> 400 ind. km−2) in the tidewater glacier bays, where kittiwakes were predominant, and the lowest in the coastal glacier bays. The seabirds in Hornsund daily consumed c. 12.7 tons of food, i.e. c. 0.2% of the summer mesozooplankton and fish standing stocks available in the fjord. This food consisted primarily of copepods, amphipods and molluscs (c. 70%), whereas fish made up < 15%. More than 50% of this biomass was ingested by pursuit divers, while surface feeders took c. 29% and benthophages c. 13%. About three-quarters of the food biomass was taken from the pelagic zone. This paper describes, for the first time in quantitative terms, the structure and function of a seabird community foraging in an Arctic fjord. It also provides a baseline for future studies on climate-induced changes in the importance of seabirds in the Arctic food web.

Per- and Polyfluoroalkyl Substances Are Positively Associated with Thyroid Hormones in an Arctic Seabird.

Per- and polyfluoroalkyl substances (PFAS) are associated with several disrupted physiological and endocrine parameters. Regarding endocrine mechanisms, laboratory studies suggest that PFAS could disrupt the thyroid hormone system and alter circulating thyroid hormone concentrations. Thyroid hormones play a ubiquitous role-controlling thermoregulation, metabolism, and reproduction. However, evidence for disruption of thyroid hormones by PFAS remains scarce in wildlife. The present study investigated the associations between concentrations of PFAS, thyroid hormones, and body condition in an arctic seabird, the black-legged kittiwake (Rissa tridactyla). We collected blood from kittiwakes sampled in Svalbard, Norway (2013 and 2014). Plasma samples were analyzed for total thyroxine (TT4) and total triiodothyronine (TT3) concentrations; detected PFAS included branched and linear (lin) C8 perfluoroalkyl sulfonates (i.e., perfluoroctane sulfonate [PFOS]) and C9 -C14 perfluoroalkyl carboxylates (PFCAs). The dominant PFAS in the kittiwakes were linPFOS and C11 - and C13 -PFCAs. Generally, male kittiwakes had higher concentrations of PFAS than females. We observed positive correlations between linPFOS, C10 -PFCA, and TT4 in males, whereas in females C12-14 -PFCAs were positively correlated to TT3. Interestingly, we observed contrasted correlations between PFAS and body condition; the direction of the relationship was sex-dependent. Although these results show relationships between PFAS and circulating thyroid hormone concentrations in kittiwakes, the study design does not allow for concluding on causal relationships related to effects of PFAS on the thyroid hormone system. Future experimental research is required to quantify this impact of PFAS on the biology of kittiwakes. The apparently different associations among PFAS and body condition for males and females are puzzling, and more research is required. Environ Toxicol Chem 2021;40:820-831. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Life in the extreme environment: Structure and species richness of bird assemblages on Yuzhny Island of Novaya Zemlya, Russia

Birds play a vital role in arctic environments, being multi-functional ecosystem engineers, but these animals are heavily impacted by recent climate warming. Bird assemblages on the Arctic Ocean archipelagoes are poorly known, because many such areas are hardly accessible to scientists. Novaya Zemlya, one of the most enigmatic places in the World, was a closed military area from the late 1940s. This gigantic mountainous archipelago can be considered a terra incognita by means of modern faunal, taxonomic, and ecological research. In the present study, we provide the first qualitative data on bird assemblages of the Yuzhny Island of Novaya Zemlya, estimate the diversity of bird species through a range of habitats, and underscore environmental factors determining the spatial distribution of avifauna in the arctic tundra biome. In terrestrial habitats, Tundra Bean Goose (Anser fabalis rossicus), Barnacle Goose (Branta leucopsis) and Snow Bunting (Plectrophenax nivalis) were the most abundant species. In freshwater and coastal marine habitats, both these Arctic-breeding goose taxa, and Black-legged Kittiwake (Rissa tridactyla), Common Eider (Somateria mollissima) and Thick-billed Murre (Uria lomvia) were the dominant species. The most species-rich bird assemblages (11-15 species) were associated with willow tundra, freshwater lakes, and coastal sea habitats, while only a few species were recorded in dry rocky habitats, open sea environments, and littoral areas of lakes and the sea. Mountain rocky heathlands covering most of the area of Yuzhny Island were scarcely populated by birds, with only a few species recorded frequently there, such as the Rough-legged Buzzard (Buteo lagopus) and Snow Bunting. Our findings highlight that the bird assemblages on Novaya Zemlya share low species richness and that these assemblages contain a large proportion of sea and shore bird species even in terrestrial habitats. Among the terrestrial birds, only four cold-tolerant, common species successfully colonize these extreme environments during the short summer season.

Foraging niche partitioning in sympatric seabird populations

Sympatric species must sufficiently differentiate aspects of their ecological niche to alleviate complete interspecific competition and stably coexist within the same area. Seabirds provide a unique opportunity to understand patterns of niche segregation among coexisting species because they form large multi-species colonies of breeding aggregations with seemingly overlapping diets and foraging areas. Recent biologging tools have revealed that colonial seabirds can differentiate components of their foraging strategies. Specifically, small, diving birds with high wing-loading may have small foraging radii compared with larger or non-diving birds. In the Gulf of St-Lawrence in Canada, we investigated whether and how niche differentiation occurs in four incubating seabird species breeding sympatrically using GPS-tracking and direct field observations of prey items carried by adults to chicks: the Atlantic puffin (Fratercula arctica), razorbill (Alca torda), common murre (Uria aalge), and black-legged kittiwake (Rissa tridactyla). Although there was overlap at foraging hotspots, all species differentiated in either diet (prey species, size and number) or foraging range. Whereas puffins and razorbills consumed multiple smaller prey items that were readily available closer to the colony, murres selected larger more diverse prey that were accessible due to their deeper diving capability. Kittiwakes compensated for their surface foraging by having a large foraging range, including foraging largely at a specific distant hotspot. These foraging habitat specialisations may alleviate high interspecific competition allowing for their coexistence, providing insight on multispecies colonial living.

Meeting Paris agreement objectives will temper seabird winter distribution shifts in the North Atlantic Ocean

We explored the implications of reaching the Paris Agreement Objective of limiting global warming to <2°C for the future winter distribution of the North Atlantic seabird community. We predicted and quantified current and future winter habitats of five North Atlantic Ocean seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia and Rissa tridactyla) using tracking data for ~1500 individuals through resource selection functions based on mechanistic modeling of seabird energy requirements, and a dynamic bioclimate envelope model of seabird prey. Future winter distributions were predicted to shift with climate change, especially when global warming exceed 2°C under a "no mitigation" scenario, modifying seabird wintering hotspots in the North Atlantic Ocean. Our findings suggest that meeting Paris agreement objectives will limit changes in seabird selected habitat location and size in the North Atlantic Ocean during the 21st century. We thereby provide key information for the design of adaptive marine-protected areas in a changing ocean.

Dark ecologies: creative research in multi-species water environments

ABSTRACT In the realm of multi-species ecologies and relationships, there are often unseen dynamics, unheeded threats and unacknowledged suppressions. The objectives of the research were to develop an experimental approach to expose some of the hidden, overlooked or ignored aspects of specific watery environments, and hidden violence of associated human-animal relationships and to reflect on the role of creative methods of activation and empathy-building in such scenarios. Using a trans-disciplinary geopoetic approach inspired by dark ecology thinking and methods based on creative provocations, this experiment offers insights into relationality around two water-connected species, the European Eel and the Black-legged Kittiwake. Adaptations of everyday objects were created and used within a performative market-stall installation to engage people in conversation. Our work illustrates the potential for creative provocation as a method within ecology-focussed enquiry, harnessing the productive tension between what is regarded as scientific ‘fact’ and creative/imaginative activations. Kittiwake; Eel; Dark Ecology; Geopoetics; Water Landscape; Hydrocitizenship

Heavy decline of the largest European Arctic Skua Stercorarius parasiticus colony: interacting effects of food shortage and predation

ABSTRACT Capsule The number of breeding pairs of Europe’s largest Arctic Skua Stercorarius parasiticus colony at Slettnes, Norway, showed a dramatic decline of at least 50% over two decades, with food shortage in four years and increasing predation by Red Fox Vulpes vulpes leading to total breeding failure in five out of six recent study years. Aims To document the decline of Europe’s largest Arctic Skua colony and quantify bottom-up and top-down effects on reproduction. Methods We compared nest counts between 1997–1998 and 2014–2019 and collected data on egg size, clutch size and nest success for all years, and adult body mass, nest attendance, at-sea activity, aggressive nest defence, Red Fox Vulpes vulpes encounters, daily nest survival and adult survival for 2014–2019. We deployed nest cameras to identify predators in 2018–2019. In addition, we developed a demographic model to estimate the fecundity required for a stable population. Results A higher proportion of time spent at sea, small eggs, low adult female body mass and indirect assessment of foraging fish availability suggested food shortages in four of six recent study years. At the same time, nest predation by Red Foxes, the likely predator involved, increased during the six-year study. The combined effects of food shortage and nest predation led to total breeding failures in 2017–2019. Conclusion We provide evidence of both bottom-up (food shortage) and top-down (predation) effects on reproductive investment and hatching success in this colony. The reproductive output in recent years is far too low to sustain a stable population. The severe decline of the Arctic Skua colony at Slettnes fits reported trends for this species across most of its European breeding range, as well as for its important host species, the Arctic Tern Sterna paradisaea and the Black-legged Kittiwake Rissa tridactyla.

Two observations of acorn barnacles attached to GLS loggers on seabirds in the North Atlantic

Two observations of acorn barnacles attached to GLS loggers on seabirds in the North Atlantic

Long-term tracking of an Arctic-breeding seabird indicates high fidelity to pelagic wintering areas

Site fidelity is driven by predictable resource distributions in time and space. However, intrinsic factors related to an individual’s physiology and life-history traits can contribute to consistent foraging behaviour and movement patterns. Using 11 yr of continuous geolocation tracking data (fall 2008 to spring 2019), we investigated spatiotemporal consistency in non-breeding movements in a pelagic seabird population of black-legged kittiwakes Rissa tridactyla breeding in the High Arctic (Svalbard). Our objective was to assess the relative importance of spatial versus temporal repeatability behind inter-annual movement consistency during winter. Most kittiwakes used pelagic regions of the western North Atlantic. Winter site fidelity was high both within and across individuals and at meso (100-1000 km) and macro scales (&gt;1000 km). Spatial consistency in non-breeding movement was higher within than among individuals, suggesting that site fidelity might emerge from individuals’ memory to return to locations with predictable resource availability. Consistency was also stronger in space than in time, suggesting that it was driven by consistent resource pulses that may vary in time more so than in space. Nonetheless, some individuals displayed more flexibility by adopting a strategy of itinerancy during winter, and the causes of this flexibility are unclear. Specialization for key wintering areas can indicate vulnerability to environmental perturbations, with winter survival and carry-over effects arising from winter conditions as potential drivers of population dynamics.

МОРСКИЕ КОЛОНИАЛЬНЫЕ ПТИЦЫ ОСТРОВА МЕДНОГО (КОМАНДОРСКИЕ ОСТРОВА)

The results of colonial seabird surveys on Medny Island were presented and the changes in numbers and distribution over the past 20–30 years were analyzed. The number of colonies on the island has not changed. The total number of individuals belonging to19 species is more than 200 thousand pairs. The colonies are distributed on the island relatively evenly along the whole coast and are based on five species – northen fulmar Fulmarus glacialis,black-legged kittiwake Rissa tridactyla, red-legged kittiwake Rissa brevirostris and two species of guillemots. The most numerous species is Northen fulmar. The abundance of the common guillemot Uria aalge has noticeably increased. The glaucous-winged gull Larus glaucescens, the crested auklet Aethia cristatella, the moth horned puffin Fratercula corniculata and the tufted puffin Lunda cirrhata has increased less. The number of parakeet auklet Cyclorrhynchus psittacula has decreased. There was not found significant changes for the rest of species.

Transpolar and bi-directional migration strategies of black-legged kittiwakes Rissa tridactyla from a colony in Novaya Zemlya, Barents Sea, Russia

Atlantic black-legged kittiwakes Rissa tridactyla tridactyla breeding in the Barents Sea have long been considered to winter in the North Atlantic region. Here, we present the first evidence of bi-directional and transpolar migrations of kittiwakes breeding in the south-eastern Barents Sea. Using geolocators, we revealed previously unknown migration patterns of kittiwakes that breed at Yuzhny (Southern) Island of the Novaya Zemlya Archipelago. Of 27 studied individuals, 21 migrated to the North Atlantic, while 6 (22%) wintered in the North Pacific. Two birds repeated an eastward migration over 3 subsequent years, and 3 kittiwakes did so over 2 years. We hypothesize that such bi-directional migration strategies can reflect the history of the kittiwakes’ colonization of the eastern Barents Sea, where North Pacific birds may have colonized Novaya Zemlya from the east and maintained their traditional wintering grounds in the Pacific. However, we also expect that the exchange of Atlantic and Pacific (Rissa t. pollicaris) kittiwakes will increase as the sea ice barrier shrinks in the following decades, potentially having a great impact on these 2 subspecies.

“Punishing” pecks and “siblicidal” pecks in kittiwake (Rissa tridactyla) chicks

The Black-legged Kittiwake gull (Rissa tridactyla) is noted for its suite of evolutionary adaptations to its extreme cliff-nesting habitat (Cullen, 1957) which distinguish it behaviourally in a number of ways from other gulls (Laridae). One such behaviour we observed was siblicide, the death of one chick from falling out of the nest as a consequence of agonistic harassment by the other (Dickins et al., 1985). This harassment involved what we termed “siblicidal pecks” inflicted by the dominant chick on its younger sib, not in the context of feeding. These we distinguished observationally from “punishing pecks”, also made by the dominant chick on its brood mate, specifically when the latter was begging for food from a parent, causing it to stop this behaviour in the short term.Though the evolution of siblicide initially seemed to present a paradox for Inclusive fitness theory it was soon seen to be a logical corollary thereof (O’Connor, 1978; Mock & Parker, 1998), and dependent upon key ecological variables. A number of subsequent studies of these factors in the kittiwake, largely from the ecological and ornithological literature, are here collated, and it is considered how these might be integrated with the application of concepts from operant psychology to chick and parent behaviours (Reed, 2015), to give a full account.