Pagodroma Nivea Research Articles

Survey of a snow petrel nesting site in a remote high mountain region to inform designation of an Antarctic Specially Protected Area

Despite the sensitivity of ecosystems in extreme conditions, only 0.029% of the Antarctic continent is currently granted special protection as Antarctic Specially Protected Area (ASPA). Additionally, protected areas are unevenly distributed and unrepresentative of the biodiversity of Antarctica. The Antarctic Treaty Consultative Parties are thus striving to establish a more coherent network of protected areas. In this context, the Otto-von-Gruber-Gebirge was identified as an area highly worthy of protection due to its unique ecosystem including one of the largest snow petrel breeding sites, and relative pristine nature. However, in the process of designation, an update of knowledge, particularly of the population status of snow petrel in the area, was recognized to be needed. This study was aimed at estimating a population census of snow petrel breeding pairs in the Lake Untersee catchment, an important subarea of the potentially protected area. Investigations were severely limited by the remoteness and harsh conditions of the area, enabling only a short fieldwork period with limited resources. Thus, a combination of remote sensing and traditional methods was applied. We conducted a ground survey of a smaller reference area, including locating nest sites and assessing nest site characteristics. Snow petrels usually nest in the cavities of large boulders and we thus classified habitat suitability based on boulder presence. To do so, the study area was remotely surveyed by unpiloted aerial vehicles to gain orthophotomosaics in sufficient resolution to distinguish on-ground conditions for breeding. We then calculated nest site densities for the reference area. We also studied nest site data such as nest cavity depth, orientation, and attendance to gain basic knowledge of the characteristics of the breeding site. Finally, we measured a sample of four live snow petrels to determine which morph was present at the site. We were able to obtain nest site data and to extrapolate it, which produced population numbers of 11,765 breeding pairs for the whole study area. This underpins the size of the breeding site and thereby its importance for the species.

Marine distribution and habitat use by Snow Petrels Pagodroma nivea in East Antarctica throughout the non-breeding period

The relationships between flying Antarctic seabirds and their at-sea environments remain poorly understood, particularly outside of the breeding season. Improving our knowledge of how these marine predators use their habitat is a critical step towards conservation of these species. We tracked 27 adult Snow Petrels from two large breeding colonies in East Antarctica during the Austral winter (non-breeding period) – when they are primarily at sea away from their nesting sites. During this time, Snow Petrel habitat use was most associated with bathymetry (> 5000 m), low sea-surface height, relatively close distance to the southern boundary of the Antarctic Circumpolar Current, relatively close distance to the ice-edge, relatively high sea-ice concentration, and low sea-surface temperature. Individuals displayed various movement patterns: 20 birds occupied overlapping winter areas that ranged broadly (up to 2000 km) from their breeding sites. The remaining birds ventured far beyond their breeding sites – reaching a maximal distance from the colony of 5,268 km. One individual circumnavigated Antarctica. Daily activity patterns were related to day length, with peak activity occurring near dawn and dusk. Nocturnal activity increased from March until August/September. Key results reveal and depict Snow Petrel habitat maps for the non-breeding period in the East Antarctic region.

How does maternal age influence reproductive performance and offspring phenotype in the snow petrel (Pagodroma nivea)?

In wild vertebrates, the increase of breeding success with advancing age has been extensively studied through laying date, clutch size, hatching success, and fledging success. However, to better evaluate the influence of age on reproductive performance in species with high reproductive success, assessing not only reproductive success but also other proxies of reproductive performance appear crucial. For example, the quality of developmental conditions and offspring phenotype can provide robust and complementary information on reproductive performance. In long-lived vertebrate species, several proxies of developmental conditions can be used to estimate the quality of the produced offspring (i.e., body size, body condition, corticosterone levels, and telomere length), and therefore, their probability to survive. By sampling chicks reared by known-aged mothers, we investigated the influence of maternal age on reproductive performance and offspring quality in a long-lived bird species, the snow petrel (Pagodroma nivea). Older females bred and left their chick alone earlier. Moreover, older females had larger chicks that grew faster, and ultimately, those chicks had a higher survival probability at the nest. In addition, older mothers produced chicks with a higher sensitivity to stress, as shown by moderately higher stress-induced corticosterone levels. Overall, our study demonstrated that maternal age is correlated to reproductive performance (hatching date, duration of the guarding period and survival) and offspring quality (body size, growth rate and sensitivity to stress), suggesting that older individuals provide better parental cares to their offspring. These results also demonstrate that maternal age can affect the offspring phenotype with potential long-term consequences.

Reconstructing the Paleo‐Ecological Diet of Snow Petrels (Pagodroma nivea) From Modern Samples and Fossil Deposits: Implications for Southern Ocean Paleoenvironmental Reconstructions

AbstractSnow petrels (Pagodroma nivea), which are endemic to the Antarctic region, produce proventricular stomach oil from ingested food for feeding purposes but also spit the oil in the immediate surrounds of the nests, where it forms encrustations over time (Antarctic mumiyo). These deposits provide a unique opportunity to understand the paleo‐ecological diet of snow petrels and because the seabirds forage in the ocean, they potentially provide an archive of past marine environmental conditions in the Southern Ocean. For validating methods for reconstructions we use compositional data obtained on modern stomach oils and DNA data from fecal samples of snow petrels. We find that the distribution of carboxylic acid compounds in modern stomach oils and in the fossil deposits are consistent with variable contributions of fish and krill, which are the main constituents of modern snow petrel diet, and allows inference of past changes in snow petrel diet from the fossil record. Analyses of mumiyo deposits from six regions in East Antarctica reveal systematic differences in the isotopic composition of organic matter (δ13C and δ15N) and carboxylic acid patterns. This may suggest regional and/or temporal variability in the composition of snow petrels diet, likely differing in response to the prevailing environmental conditions in the foraging range of the birds, such as sea‐ice variability, polynya activity and primary productivity. Our study provides confidence for using these approaches for broader scale paleo‐studies in the future and for an assessment of the temporal changes and regional variability in snow petrel diet.

Extreme snowstorms lead to large-scale seabird breeding failures in Antarctica

Climate change increases the frequency and intensity of extreme weather events that negatively impact wildlife, from individuals to whole ecosystems1. In polar environments, such events include heat waves2, anomalous sea ice concentrations3 and storms4. Polar seabirds are adapted to withstand harsh conditions, and although extreme weather events affect their breeding success and other demographic rates, they are thought to affect only a part of the population. Complete breeding failure of an entire population due to extreme environmental conditions is rarely observed5. Here we report how exceptional storm activity in Dronning Maud Land (DML), Antarctica, in the austral summer of 2021/2022 caused almost complete and large-scale breeding failures of the area's three most common seabird species - Antarctic petrel (Thalassoica antarctica), Snow petrel (Pagodroma nivea) and South polar skua (Stercorarius maccormicki).

Snow petrel stomach-oil deposits as a new biological archive of Antarctic sea ice

Snow petrel stomach-oil deposits as a new biological archive of Antarctic sea ice

Analysis of the attempts to breed seabirds in uninhabited territories of the Haswell archipelago and Adams Island (East Antarctica)

Data on new breeding sites of seabirds in Antarctica allow a better understanding of spatial species distribution, correct population estimates, and the processes occurring in populations and ecosystems. The aim of the work is to compile and analyze knowledge about the spatial distribution of breeding seabird populations and attempts to breed in new, previously uninhabited territories. Ground-based observations and population counts were conducted at the Haswell archipelago (Queen Mary Land, Davis Sea) by several observers from 1912 to 2016. The total area studied was 12 km². An aerial census of penguins on Adams Island was conducted in 2011. Based on this census, it might be stated that 6 out of 9 breeding species of seabirds have made attempts to develop new breeding sites. Regular breeding of birds within the archipelago is established on 8 islands. Emperor Penguins (Aptenodytes forsteri), Snow Petrels (Pagodroma nivea) and South Polar Skuas (Stercorarius maccormicki) showed no change in spatial distribution. Adélie Penguins (Pygoscelis adeliae), Southern Fulmars (Fulmarus glacialoides), Cape Petrels (Daption capense) and mixed pairs of Brown Skua (Stercorarius antarcticus) × ​​South Polar Skua bred in new sites (6 islands and 1 nunatak). New likely breeding sites have been recorded for the Southern Fulmar, Cape Petrel and Wilson's Storm Petrel (Oceanites oceanicus). An unsuccessful breeding attempt in a previously uninhabited territory has been observed in the Antarctic Petrel (Thalassoica antarctica). New breeding sites for seabirds may result from the avoidance of predation by South Polar Skuas. Changes in local meteorological conditions could be a factor contributing to the breeding attempts by seabirds in the territories previously uninhabited by them. The increase in South Polar Skuas populations, invasion of Brown Skuas on the Haswell Islands, increased breeding attempts and occupation of new breeding sites by Adélie Penguins and tube-nosed seabirds in the early 21st century are evidence of changes in ecological conditions in the local ecosystem.

Ontogeny and individual heterogeneity of the corticosterone stress response in a wild altricial seabird, the snow petrel (Pagodroma nivea)

In the current context of global change, there is evidence of a large inter-individual variability in the way animals physiologically respond to anthropogenic changes. In that context, the Hypothalamus-Pituitary-Adrenal (HPA) axis and the corticosterone stress response are of primary importance because they are thought to govern the ability of individuals to adjust to stress. Several studies have reported that this stress response is variable among adults and they have successfully linked this variability with abiotic and biotic factors. However, the inter-individual variability of the glucocorticoid stress response has rarely been examined during the developmental phase in wild vertebrates, and its potential ecological determinants remain unclear. In this study, we examined the ontogeny of the corticosterone stress response in an altricial seabird species (i.e., how corticosterone levels increase in response to a standardized stress protocol), the Snow petrel. We reported a strong heterogeneity of the corticosterone stress response at all ages in snow petrel chicks (11-, 20-, and 37-days old chicks). Although the magnitude of this corticosterone stress response decreases with the age of the chick, we also found that this corticosterone stress response was repeatable throughout the post-hatching developmental period (repeatability: r > 0.50 for stress-induced corticosterone levels after a 30-min restraint). Importantly, this glucocorticoid stress response was negatively associated with the body condition of the chicks (i.e., mass corrected for body size), and previous exposure to sampling was associated with a dampened corticosterone stress response. However, we did not find any link between parental traits (parental condition or parental corticosterone stress response), nest quality, hatching date, and the chick’s corticosterone stress response. Our study suggests that the corticosterone stress response is a consistent individual trait that is affected to some extent by post-natal conditions, and which differs among individuals very early in life.

New and legacy persistent organic pollutants (POPs) in breeding seabirds from the East Antarctic

Persistent organic pollutants (POPs) are pervasive and a significant threat to the environment worldwide. Yet, reports of POP levels in Antarctic seabirds based on blood are scarce, resulting in significant geographical gaps. Blood concentrations offer a snapshot of contamination within live populations, and have been used widely for Arctic and Northern Hemisphere seabird species but less so in Antarctica. This paper presents levels of legacy POPs (polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs)) and novel brominated flame retardants (NBFRs) in the blood of five Antarctic seabird species breeding within Prydz Bay, East Antarctica. Legacy PCBs and OCPs were detected in all species sampled, with Adélie penguins showing comparatively high ∑PCB levels (61.1 ± 87.6 ng/g wet weight (ww)) compared to the four species of flying seabirds except the snow petrel (22.5 ± 15.5 ng/g ww), highlighting that legacy POPs are still present within Antarctic wildlife despite decades-long bans. Both PBDEs and NBFRs were detected in trace levels for all species and hexabromobenzene (HBB) was quantified in cape petrels (0.3 ± 0.2 ng/g ww) and snow petrels (0.2 ± 0.1 ng/g ww), comparable to concentrations found in Arctic seabirds. These results fill a significant data gap within the Antarctic region for POPs studies, representing a crucial step forward assessing the fate and impact of legacy POPs contamination in the Antarctic environment.

Summer sea-ice variability on the Antarctic margin during the last glacial period reconstructed from snow petrel (<i>Pagodroma nivea</i>) stomach-oil deposits

Abstract. Antarctic sea ice is a critical component of the climate system affecting a range of physical and biogeochemical feedbacks and supporting unique ecosystems. During the last glacial stage, Antarctic sea ice was more extensive than today, but uncertainties in geological (marine sediments), glaciological (ice core), and climate model reconstructions of past sea-ice extent continue to limit our understanding of its role in the Earth system. Here, we present a novel archive of past sea-ice environments from regurgitated stomach oils of snow petrels (Pagodroma nivea) preserved at nesting sites in Dronning Maud Land, Antarctica. We show that by combining information from fatty acid distributions and their stable carbon isotope ratios with measurements of bulk carbon and nitrogen stable isotopes and trace metal data, it is possible to reconstruct changing snow petrel diet within Marine Isotope Stage 2 (ca. 24.3–30.3 cal kyr BP). We show that, as today, a mixed diet of krill and fish characterizes much of the record. However, between 27.4 and 28.7 cal kyr BP signals of krill almost disappear. By linking dietary signals in the stomach-oil deposits to modern feeding habits and foraging ranges, we infer the use by snow petrels of open-water habitats (“polynyas”) in the sea ice during our interval of study. The periods when consumption of krill was reduced are interpreted to correspond to the opening of polynyas over the continental shelf, which became the preferred foraging habitat. Our results show that extensive, thick, and multiyear sea ice was not always present close to the continent during the last glacial stage and highlight the potential of stomach-oil deposits as a palaeoenvironmental archive of Southern Ocean conditions.

The same pathway to the Weddell Sea birdlife, after 65 years: similarities in the species composition, richness and abundances

As part of a multi-year study of top predators in Antarctica, we conducted a seabird shipbased survey on board Almirante Irizar icebreaker in the Weddell Sea to the Filchner Ice Shelf in the austral summer 2020. We carried out 10-minute counts along 1843 km during 125 hours of observation. We analyzed the species distributions and the relationships with the ice cover. We registered 15 species of which four represented more than 85% of the total abundance: Antarctic petrel Thalassoica antarctica (43.9%), snow petrel Pagodroma nivea (16.3%), Arctic tern Sterna paradisaea (15.2%) and emperor penguin Aptenodytes forsteri (10.1%). Species distribution and its relationship with ice cover were analyzed statistically. The ice cover concentration was estimated by using satellite images. We compared our results with the first ship-based bird survey conducted up to the Filchner Ice Shelf in the austral summer 1955/56 to analyze possible changes in the bird community over time. Out of 13 recorded species in the 1955/56 cruise, 11 were present in this study with similar abundance proportions. In both cruises, the bird community consisted of a group of non-numerous species associated with icefree waters and another group of very numerous species associated with high concentrations on ice cover. The similarities between the two cruises, spaced 65 years apart, suggest a temporal persistence of the bird community of the central and the southern Weddell Sea that could be explained by the dynamics of the ice cover and the presence of reproductive colonies within the study site. The current environmental warming is alarming in this bird community because more than 85% of all its individuals belong to four species strongly dependent on ice cover.

Sea ice and local weather affect reproductive phenology of a polar seabird with breeding consequences

Abstract Breeding at the right time is essential for animals living in seasonal environments to ensure that energy requirements for reproduction, especially the nutritional needs for rearing offspring, coincide with peak food availability. Climate change is likely to cause modifications in the timing of maximum food availability, and organisms living in polar environments where the breeding period is heavily contracted may be particularly affected. Here we used a 26-year dataset to study the phenological response of a pagophilic species, the Snow Petrel (Pagodroma nivea), to climate change and its demographic impact. First, we investigated the trends and relationships between climate variables and hatching dates measured in three neighboring colonies. In a second step, we examined the impact of the hatching date and environmental covariates on the fledging probability. Our results showed that sea ice, a climate-related variable, showed a positive temporal trend. We found that hatching date was delayed when sea ice concentration was greater and local weather conditions were worse (i.e., increase in the number of windy days or the number of snow days). Hatching date had a negative effect on fledging probability, and fledging probability showed a bell-shaped temporal trend. We suggest that Snow Petrels can delay breeding phenology in response to environmental conditions. However, this plasticity may be limited as fledging success decreased with delayed hatching, potentially making the Snow Petrel vulnerable to a mismatch between resource availability and nutritional needs.

Comparative egg attendance patterns of incubating polar petrels

BackgroundThe internal environment of eggs in most birds is regulated by transferring heat energy through contact incubation, maintaining nest microclimate, and frequent egg turning by the incubating parent on its nest. However, we lack information about egg attendance patterns in birds that breed in polar environments where variations in life history are expected to influence incubation behavior. Moreover, crevice/burrow nesting petrels in high-latitude regions are known for periodically leaving their egg unattended (hereafter ‘egg neglect’), but there is little reporting on the internal condition of unattended eggs. At Dumont d’Urville Station, Antarctica, we studied the incubation behavior of 24 snow (Pagodroma nivea) and 15 Cape (Daption capense) petrel pairs using egg loggers that recorded egg turning rates, orientation changes, and temperatures at 1 Hz for durations of 3–6 days.ResultsEgg turning frequency (1.31 ± 0.33 vs. 1.38 ± 0.39 turns h−1), angle change per turn (43.1 ± 43.2 vs. 48.6 ± 43.7° turn−1), and egg temperature (34.1 ± 2.3 vs. 34.1 ± 2.0 °C) were nearly identical for snow and Cape petrels, respectively. However, egg neglect was only observed in snow petrel nests (based on egg temperature changes) where loggers recorded mean durations of 1.34 ± 1.15 days (maximum duration of 3.63 days). During periods of neglect, eggs cooled to 5.5 ± 1.8 °C over an average of 91 min, but were rewarmed by parents in only 76 min at a rate of 0.33 °C min−1.ConclusionsEgg temperatures of both species during regular incubation were within 1–2 °C of other high-latitude petrel species, but neglected snow petrel eggs remained several degrees above freezing, which was likely attributed to crevice nesting where neglected eggs are buffered by environmental conditions. Using egg rewarming rates, thermal capacity of eggs, and published metabolic rates, we estimate egg rewarming costs in snow petrels to be 1.5 to 1.9 × BMR. Excluding egg neglect periods, turning rates for both petrel species were lower than other seabirds studied using biologging devices, which may be associated with the prolonged incubation periods that are characteristic of procellariiform seabirds.

Very Low Density and Biodiversity of Seabird and Marine Mammal at-sea Distribution in the Amundsen Sea, 2010

Our long-term study on the quantitative at-sea distribution of the upper trophic levels - seabirds and marine mammals - in polar ecosystems aims at quantifying the factors influencing their distribution as well as detecting possible spatial and temporal changes, with special attention to hydrography and global climate changes. During the ANT- XXVI/3 expedition of icebreaking RV Polarstern in February-March 2010, a total of 8,270 seabirds belonging to 15 identified species were recorded in the Amundsen Sea during 1,070 half-hour transect counts, with a mean of eight birds per count. The most numerous species were by far Antarctic petrel, Adélie penguin and snow petrel, which together accounted for more than 80% of all individuals of these species recorded. Substantial hotspots of seabirds perched on three icebergs, representing 44% of all observations: 85% of the Antarctic petrels and 40% of the snow petrels [1]. Without taking into account these data, the mean seabird number becomes five individuals per count, representing the lowest value registered in Antarctic seas. The most numerous pinniped was crabeater seal contributing 98% of the total of 2,350 individuals of four pinniped species [2]. Among cetaceans, the most abundant species were Antarctic Minke whale and fin whale (60% and 25% of the total of 170 individuals, four species). The maps allow for a visual comparison that is sufficient for the purposes of this article, reflecting the influence of hydrological features such as water masses and fronts, pack ice and ice edge, free drifting icebergs.

Demographic sensitivity to environmental forcings: a multi‐trait, multi‐colony approach

Understanding the demographic responses of wild animal populations to different factors is fundamental to make reliable prediction of population dynamics. Both bottom–up processes and top–down regulation operate in terrestrial and marine ecosystems, but their relative contribution remains insufficiently known. In addition, direct weather effects on demographic rates have been overlooked in marine ecosystems and inferences on the demographic effects of environmental drivers were overwhelmingly made from single study sites. Here, we evaluate the relative effects of bottom–up, top–down and weather processes on four vital rates and on population growth rates of a long‐lived seabird, the snow petrel Pagodroma nivea, within three different breeding colonies. We used multistate capture–recapture modelling and perturbation analyses from a matrix population model based on a 36‐year‐long (1981–2017) individual monitoring dataset to quantify the different drivers (predation, climatic and weather covariates) of probabilities of survival, breeding, hatching and fledging according to colony, sex and breeding status of individuals. Results show that bottom–up forces and local weather affected breeding parameters, and that survival was driven by top–down regulation pressure and bottom–up processes. Breeding parameters differed between colonies and survival was sex‐specific. Sensitivity analysis revealed that population regulation was mainly driven by bottom–up processes and that top–down processes played a minor role. However, there were major differences between colonies about the importance of how local weather processes affected population growth rate. Our study brings new insights into the drivers of demographic processes in a marine meso‐predator, and how these drivers vary according to colonies and individual characteristics. We emphasize the importance of considering multiple study sites to make robust inferences on the effects of environmental drivers on wildlife demography. More generally, robust conclusions about the importance of environmental drivers on demography rely on considering multiple causal effects at multiple sites, while accounting for individual characteristics.

“Home alone!” influence of nest parental attendance on offspring behavioral and hormonal stress responses in an Antarctic seabird, the snow petrel (Pagodroma nivea)

In altricial species, parents brood their chicks constantly before leaving them unattended sometimes for extended periods when they become thermally independent. During this second phase, there is sometimes important inter-individual differences in parental attendance and the fitness costs and benefits of parental strategies have previously been extensively investigated. However, the impact of parental presence on offspring behaviors and stress physiology has been overlooked. Here, we examined the influence of parental presence on offspring hormonal and behavioral stress sensitivities in snow petrel chicks. We demonstrated for the first time in a wild bird species that attended chicks had lower stress-induced corticosterone levels and a lower probability to show defensive behavior compared to the alone chicks. This reduced stress sensitivity is certainly explained by the well-known link between corticosterone and nutritional status, and by the recent delivery of meals to the attended chicks and the improvement of their nutritional status. It may also be explained by the parental protection against predators or inclement weather, or/and by the psychosocial comfort of parental presence for the offspring. Overall, these results suggest that the presence of a parent in the nest reduces offspring stress sensitivity in wild birds. Further studies would now be required to disentangle the impact of nutritional status and parental presence on stress sensitivity and to better understand the potential impact of parental presence and circulating corticosterone levels on growth and cognitive development in wild birds.

Polymer types ingested by northern fulmars (Fulmarus glacialis) and southern hemisphere relatives

Although ingestion of plastic by tubenosed seabirds has been documented regularly, identification of the polymer composition of these plastics has rarely been described. Polymer assessment may assist in identifying sources and may indicate risks from additives occurring in specific types of polymers. Using known test materials, two identification methods Fourier transform infrared spectroscopy and near infrared spectroscopy (FTIR and NIR) were compared. Although both methods were found to be similarly suitable for identification of plastic polymers, a significant difference was observed in identification of natural materials. FTIR frequently misclassified natural materials as being a synthetic polymer. Within our results, an 80% match score threshold functioned best to distinguish between natural items and synthetics. Using NIR, the historical variability of plastics ingested by northern fulmars (Fulmarus glacialis) from the Dutch sector of the North Sea was analysed for three time periods since the 1980s. For the more recent decade, variability between fulmars from different regions in the northeast Atlantic was investigated. Regional variation was further explored by analysing plastics obtained from the stomachs of southern hemisphere relatives of the fulmar (southern fulmar, cape petrel, snow petrel) and Wilson’s storm petrel. Results show that proportional abundance of polymer types in these seabirds is closely related to the plastic categories that they ingest (e.g. pellets, foam, fragments). The uptake of different plastic categories and related polymer types most likely reflects spatial and temporal variations in availability rather than ingestion preferences of the birds.

Complete mitochondrial genome of the snow petrel, Pagodroma nivea

The snow petrel, Pagodroma nivea is a small sea bird endemic to Antarctica and the Southern Ocean. Herein, we assembled a complete mitochondrial genome of the snow petrel as a first revealed genetic resource in Pagodroma family. The mitogenome is 17,279 bp in length and consists of 13 protein-coding genes (PCGs), 22 tRNA genes, and two rRNA genes. Base composition is 31.3% A, 25.3% T, 30.1% C, and 13.2% G with CG content of 43.4%. These results will provide a useful basis for further genetic and phylogenetic studies of this species.

Do repeated captures and handling affect phenotype and survival of growing Snow Petrel (Pagodroma nivea)?

In vertebrates, developmental conditions can affect not only fledging success but also the phenotype of the offspring, with potential long-term consequences on adult performance. However, surprisingly the potential impact of anthropogenic disturbance on developing chicks is rarely investigated, notably in Antarctic wildlife. In this study, we specifically investigated the effects of repeated nest visits, capture, and handling on offspring survival and several complementary offspring phenotypic traits in the Snow Petrel (Pagodroma nivea) chicks after thermal emancipation. We did not find any significant effect of our disturbance protocol on the morphology (body size, body mass, body condition), the physiology (breath rate, stress-induced corticosterone levels) and the behaviour (defense behaviour) of developing Snow Petrels. This specific disturbance protocol did not have any significant effect on chick survival, but there was a non-significant trend towards a lower survival for the disturbed group (p = 0.1006), which showed an especially high mortality during a period of repeated snow storms. To conclude, investigator disturbance seems to have little effect on Snow Petrel chicks after thermal emancipation, but to remain cautious, we recommend to avoid capture and handling of Snow Petrel chicks during or soon after inclement weather.

Spatial distribution of birds and terrestrial plants in Bunger Hills

AbstractIn this paper, we synthesize recorded observations of moss, lichen and bird species in Bunger Hills, East Antarctica, and assess the role of environmental controls, including sediment, salinity, moisture and geology, on species' distributions. The distribution of snow petrels (Pagodroma nivea) appears to be associated with geology; they nest by preference in crevices in bedrock outcrops around the margins of the hills or wherever jointed cliffs are found. South polar skuas (Catharacta maccormicki) are seen throughout Bunger Hills, where they nest and prey on snow petrels. Mosses and lichens were most abundant around the ice margins where fresh snow and ice meltwater are abundant. In the central area of Bunger Hills, where the highest salt concentration in sediments is found and exposure to abrasion by wind-driven mineral sand grains and ice particles is greatest, mosses and lichens are reduced in abundance and diversity. Exposure of parts of Bunger Hills from the ice sheet throughout the Last Glacial Maximum,c.20 kabp, means that some land and lakes could have acted as regional refugia and as a locus of recolonization of other ice-free areas.