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Abandoned rookeries belonging to any of the Pygoscelis species are very particular taphocoenosis, usually preserved due to the accumulations of bones, pebbles, and guano year after year in the same nesting area, that condense together with other biogenic material and form ornithogenic sediments. The results of the excavation, sieved and analyses of sediment and materials found in two rookeries formed during the last 8000 years, named Pingfo I and Pingfo II and found in the 25 de Mayo/King George Island (South Shetland Islands, West Antarctica) are presented here. The analyses of the bones and eggshells, taxonomic and ontogenetic composition, elements representation, transport degree, predation, and scavenging marks, together with the micropalaeontological content provided informative tools for the reconstruction of the nesting areas, suggesting that bones were transported and accumulated in Pingfo I that would represent high energy beach, whereas a breeding colony was settled in Pingfo II. The preservation of hexactinellid spicules and several arthropod remains are particularly informative for the levels at Pingfo I. The preservation of a Culicidae (Diptera) wing could be the first middle Holocene record of the group in Antarctica, the only continent without extant mosquitoes. [ABSTRACT FROM AUTHOR]

When suitable nesting habitat is rare, birds may have to share it with heterospecific individuals with similar nesting requirements. The resulting species mosaic may in turn affect how breeding birds communicate vocally with each other. For instance, they may modify their vocalizations if the ambient noise produced by heterospecifics interferes with their own vocalizations. The colonies of Gentoo Penguins (Pygoscelis papua ellsworthi) are interesting to examine whether such a vocal variation occurs in colonial seabirds, as these birds frequently breed in the same colony as Adélie (P. adeliae) or Chinstrap (P. antarcticus) penguins. We investigated whether the presence of congeneric penguins breeding in the same colony as Gentoo Penguins affected the acoustic characteristics of their most common vocalization, the ecstatic display call. Based on vocalizations recorded in 23 breeding colonies along the Antarctic Peninsula during 3 field seasons, we found that the frequency of ecstatic display calls of Gentoo Penguins was consistently lower (average exhale phrase ~460 Hz lower, average inhale phrase ~370 Hz lower) as well as decreased in energy distribution when they bred in mixed colonies with Adélie Penguins than when they bred only in proximity to conspecifics. In contrast, the frequency of both inhale and exhale phrases was unaffected by the presence of Chinstrap Penguins, potentially due to the already greater frequency difference between these 2 species. The apparent vocal plasticity, in mixed colonies with Adélie Penguins, likely allows Gentoo Penguins to adjust the quality of their vocalizations depending on the acoustic space available in their colonies, and hence possibly enhance signal transmission between conspecifics. However, whether this acoustic adjustment is sufficient to increase the detectability of vocalizations and localization of individuals has yet to be determined. [ABSTRACT FROM AUTHOR]

Abstract Gentoo penguins (Pygoscelis papua) are found across the Southern Ocean with a circumpolar distribution and notable genetic and morphological variation across their geographic range. Whether this geographic variation represents species‐level diversity has yet to be investigated in an integrative taxonomic framework. Here, we show that four distinct populations of gentoo penguins (Iles Kerguelen, Falkland Islands, South Georgia, and South Shetlands/Western Antarctic Peninsula) are genetically and morphologically distinct from one another. We present here a revised taxonomic treatment including formal nomenclatural changes. We suggest the designation of four species of gentoo penguin: P. papua in the Falkland Islands, P. ellsworthi in the South Shetland Islands/Western Antarctic Peninsula, P. taeniata in Iles Kerguelen, and a new gentoo species P. poncetii, described herein, in South Georgia. These findings of cryptic diversity add to many other such findings across the avian tree of life in recent years. Our results further highlight the importance of reassessing species boundaries as methodological advances are made, particularly for taxa of conservation concern. We recommend reassessment by the IUCN of each species, particularly P. taeniata and P. poncetii, which both show evidence of decline.

The salt gland is a well-developed osmoregulation organ in marine birds, and its relative size often reflects an individual’s feeding environment and osmoregulation capability. The development and functions of salt glands have been described for the Adélie penguin (Pygoscelis adeliae), but this information has been poorly documented in the other two pygoscelid species: gentoo (P. papua) and chinstrap penguins (P. antarcticus). To describe the growth-related changes in salt gland masses in relation to chick growth, we measured the wet mass of the salt glands collected from dead gentoo and chinstrap chicks during the early breeding period. The mass of the salt glands was linearly proportional to their body measurements, especially to body mass, in both species, and no significant difference was detected between the two species. Penguins are obligate marine dwellers throughout their life cycle, and the development of the salt gland in penguin chicks suggests that their ability to regulate dietary osmotic stress begins at an early stage of development after hatching. Furthermore, the linear relationship between the gland mass and body mass also suggests that the osmoregulation capability may continue to develop as penguin chicks grow. This descriptive note provides novel and quantitative information on the early developmental pattern of salt glands in gentoo and chinstrap penguins.

Global targets for area-based conservation and management must move beyond threshold-based targets alone and must account for the quality of such areas. In the Southern Ocean around Antarctica, a region where key biodiversity faces unprecedented risks from climate change and where there is a growing demand to extract resources, a number of marine areas have been afforded enhanced conservation or management measures through two adopted marine protected areas (MPAs). However, evidence suggests that additional high quality areas could benefit from a proposed network of MPAs. Penguins offer a particular opportunity to identify high quality areas because these birds, as highly visible central-place foragers, are considered indicator species whose populations reflect the state of the surrounding marine environment. We compiled a comprehensive dataset of the location of penguin colonies and their associated abundance estimates in Antarctica. We then estimated the at-sea distribution of birds based on information derived from tracking data and through the application of a modified foraging radius approach with a density decay function to identify some of the most important marine areas for chick-rearing adult penguins throughout waters surrounding Antarctica following the Important Bird and Biodiversity Area (IBA) framework. Additionally, we assessed how marine IBAs overlapped with the currently adopted and proposed network of key management areas (primarily MPAs), and how the krill fishery likely overlapped with marine IBAs over the past five decades. We identified 63 marine IBAs throughout Antarctic waters and found that were the proposed MPAs to be adopted, the permanent conservation of high quality areas for penguin species would increase by between 49 and 100% depending on the species. Furthermore, our data show that, despite a generally contracting range of operation by the krill fishery in Antarctica over the past five decades, a consistently disproportionate amount of krill is being harvested within marine IBAs compared to the total area in which the fishery operates. Our results support the designation of the proposed MPA network and offer additional guidance as to where decision-makers should act before further perturbation occurs in the Antarctic marine ecosystem.

Gentoo penguins (Pygoscelis papua) are found across the Southern Ocean with a circumpolar distribution and notable genetic and morphological variation across their geographic range. Whether this geographic variation represents species‐level diversity has yet to be investigated in an integrative taxonomic framework. Here, we show that four distinct populations of gentoo penguins (Iles Kerguelen, Falkland Islands, South Georgia, and South Shetlands/Western Antarctic Peninsula) are genetically and morphologically distinct from one another. We present here a revised taxonomic treatment including formal nomenclatural changes. We suggest the designation of four species of gentoo penguin: P. papua in the Falkland Islands, P. ellsworthi in the South Shetland Islands/Western Antarctic Peninsula, P. taeniata in Iles Kerguelen, and a new gentoo species P. poncetii, described herein, in South Georgia. These findings of cryptic diversity add to many other such findings across the avian tree of life in recent years. Our results further highlight the importance of reassessing species boundaries as methodological advances are made, particularly for taxa of conservation concern. We recommend reassessment by the IUCN of each species, particularly P. taeniata and P. poncetii, which both show evidence of decline. [ABSTRACT FROM AUTHOR]

Diet studies of marine predators provide insights into the functioning and structure of marine ecosystems. Such studies have been greatly enhanced in recent years with technology enabling direct observation of feeding behaviour in the marine environment. We here report on observations of an interesting predation event involving Gentoo penguins (Pygoscelis papua) at sub-Antarctic Marion Island. Through the deployment of an animal-borne miniaturised video data logger, we were able to document what is to our knowledge the largest recorded prey species consumed by a Gentoo penguin. A squid (probably Greater hooked squid, Onykia ingens) with an estimated mantle length of 240 mm was consumed whole after a period of competition over the prey item with another foraging Gentoo penguin. [ABSTRACT FROM AUTHOR]

In the krill-based ecosystem of the Antarctic, fluctuations in the distribution and abundance of Euphausia superba may have strong impacts on predator populations; thus, it is crucial to observe the feeding ecology of Antarctic predators, especially in the light of climate change and increasing human pressure. We determined the composition of euphausiid species in diet samples collected from Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarcticus) and gentoo (Pygoscelis papua) penguins on King George Island (South Shetlands Islands) during a breeding season. For all three penguin species, euphausiids (mainly E. superba) represented almost the entirety of researched stomach samples (i.e. 99.9% in the case of Adélie and chinstrap penguins), while gentoo penguins also proved to feed on fish (99.4% krill; 0.5% fish). Analysed material differed in the size of eaten E. superba specimens, with the smallest crustaceans consumed by Adélie penguins. Furthermore, we found differences in the ratio of consumed krill and krill size. Such disparities may be a result of sex-based differences and slight differences in feeding areas between the birds. Additionally, we noted some fragments of plastic debris in the investigated penguin diet samples. [ABSTRACT FROM AUTHOR]

The salt gland is a well-developed osmoregulation organ in marine birds, and its relative size often reflects an individual’s feeding environment and osmoregulation capability. The development and functions of salt glands have been described for the Adélie penguin (Pygoscelis adeliae), but this information has been poorly documented in the other two pygoscelid species: gentoo (P. papua) and chinstrap penguins (P. antarcticus). To describe the growth-related changes in salt gland masses in relation to chick growth, we measured the wet mass of the salt glands collected from dead gentoo and chinstrap chicks during the early breeding period. The mass of the salt glands was linearly proportional to their body measurements, especially to body mass, in both species, and no significant difference was detected between the two species. Penguins are obligate marine dwellers throughout their life cycle, and the development of the salt gland in penguin chicks suggests that their ability to regulate dietary osmotic stress begins at an early stage of development after hatching. Furthermore, the linear relationship between the gland mass and body mass also suggests that the osmoregulation capability may continue to develop as penguin chicks grow. This descriptive note provides novel and quantitative information on the early developmental pattern of salt glands in gentoo and chinstrap penguins. [ABSTRACT FROM AUTHOR]

In 2017/18, we recorded multiple instances of Adelie Penguin Pygoscelis adeliae nests containing three chicks at Cape Crozier, Ross Island, Antarctica. In one sub-colony, 0.67 % of nests had three chicks, or two chicks and one egg. We found that some Adelie Penguin pairs were willing to brood three chicks, as well as chicks that were not their own. Many factors could lead to supra-normal clutches and broods, including foreign eggs added to a nest, adoption of chicks belonging to other parents, and double-yolked eggs. In order to understand the true cost of colonial breeding in large Adelie Penguin colonies and to assess the source of chicks or eggs in supra-normal clutches and broods, we conclude that future studies should examine the frequency of supra-normal clutches and broods and analyze the genetics of chicks within sub-colonies. [ABSTRACT FROM AUTHOR]

An unmanned aerial vehicle (UAV) as an alternative to manned aircrafts is an excellent, less invasive, safe tool, especially in sensitive polar regions. Here we used a fixed-wing UAV to collect data on seabird and pinniped populations in hardly accessible Antarctic areas. The implementation of an auto-piloted UAV equipped with a digital camera (Canon EOS 700D, 35 mm f/2.0 lens) allowed us to collect high-quality material applicable to a quantitative analysis of the fauna populations. A successful photogrammetric mission, at an altitude of 550 m above sea level, was accomplished during one Beyond Visual Line of Sight flight above hard-to-access Penguin Island and Turret Point Oasis (King George Island). Obtained selected RGB images were processed to generate a panoramic image stitch with resolution of 0.07 m ground sampling distance. A total of 4290 (SD = 33.08) breeding individuals of two penguin species, Adélie (Pygoscelis adeliae) and chinstrap (Pygoscelis antarcticus), 426 (SD = 7.78) individuals of the southern elephant seal (Mirounga leonina) and 6 individuals of the Weddell seal (Leptonychotes weddellii) were identified in both study areas. Additionally, 222 (SD = 2.0) individuals of the southern giant petrel (Macronectes giganteus) and 76 (SD = 1.0) of the Antarctic shag (Phalacrocorax atriceps bransfieldensis) in the Turret Point area were recognized. The presented observations on the natural history of the investigated fauna together with the available literature may be useful in future research on population trends. A comparison with available historical data for both investigated areas suggests a decrease of 68.29% in both penguin species in the 1980-2016 period. The presented results confirmed that UAVs are useful for remote census work for Antarctic seabirds. [ABSTRACT FROM AUTHOR]

The British Antarctic Territory (BAT) is a UK Overseas Territory that includes the Antarctic Peninsula and Weddell Sea, extending from 60°S to the South Pole. It has 19 species of regularly breeding birds and is particularly significant for Emperor Aptenodytes forsteri, Gentoo Pygoscelis papua, Chinstrap P. antarcticus and Adelie Penguins P. adeliae, Southern Giant Petrel Macronectes giganteus, Cape Petrel Daption capense, Southern Fulmar Fulmarus glacialoides and Snow Petrel Pagodroma nivea. The oceanic and shelf waters within BAT are important feeding grounds for a number of albatrosses and petrels that breed farther north. Several of these species are globally Near Threatened and require urgent action to improve their conservation status. Over 40 occasional visitors and vagrants have been recorded from BAT; many are seabirds but there are also ducks and waders that have overshot their wintering grounds in Patagonia, and a few passerines. Current threats to the avifauna include marine plastics and incidental mortality in longline and trawl fisheries outside Antarctica. Fishing within the Southern Ocean is now well regulated but albatrosses and petrels are still killed in large numbers in more distant fisheries. The western Antarctic Peninsula has undergone a strong regional warming, leading to marked shifts in the breeding distribution of pygoscelid penguins. While such shifts have occurred in the past as the regional climate has warmed and cooled, the warming of the eastern Antarctic Peninsula is unprecedented in at least the last two millennia. [ABSTRACT FROM AUTHOR]

The mechanisms that determine patterns of species dispersal are important factors in the production and maintenance of biodiversity. Understanding these mechanisms helps to forecast the responses of species to environmental change. Here, we used a comparative framework and genomewide data obtained through RAD‐Seq to compare the patterns of connectivity among breeding colonies for five penguin species with shared ancestry, overlapping distributions and differing ecological niches, allowing an examination of the intrinsic and extrinsic barriers governing dispersal patterns. Our findings show that at‐sea range and oceanography underlie patterns of dispersal in these penguins. The pelagic niche of emperor (Aptenodytes forsteri), king (A. patagonicus), Adélie (Pygoscelis adeliae) and chinstrap (P. antarctica) penguins facilitates gene flow over thousands of kilometres. In contrast, the coastal niche of gentoo penguins (P. papua) limits dispersal, resulting in population divergences. Oceanographic fronts also act as dispersal barriers to some extent. We recommend that forecasts of extinction risk incorporate dispersal and that management units are defined by at‐sea range and oceanography in species lacking genetic data. [ABSTRACT FROM AUTHOR]

It is established that haematological and biochemical parameters provide important data to assess the physiological condition and health status of wild birds. To undertake conservation physiology or ecophysiology work, it is therefore essential to establish baseline physiological parameters and how these parameters change with age and life history events. In this work, we determined and compared baseline haematology and serum biochemistry between adults and chicks of three Antarctic penguin species of the genus Pygoscelis: gentoo (P. papua), Adélie (P. adeliae) and chinstrap (P. antarcticus). Differences in adults among species were observed in haemoglobin and biochemical parameters such as total proteins, glucose and alkaline phosphatase activity. In addition, differences between adults and chicks in haematocrit, haemoglobin, total proteins and glucose concentration were determined. Moreover, we evaluated the electrophoretic protein profiles between adults and chicks of the genus Pygoscelis, and a conserved protein pattern was observed among species and ages in the genus. Altogether, the results suggest that biochemical and haematological differences among pygoscelids may be related to the nutritional status and energetic expenditure during breeding as well as their feeding habits and development stage.

Climate‐induced range overlap can result in novel interactions between similar species and potentially lead to competitive exclusion. The West Antarctic Peninsula (WAP) is one of the most rapidly warming regions on Earth and is experiencing a poleward climate migration from a polar to subpolar environment. This has resulted in a range expansion of the ice‐intolerant gentoo penguins (Pygoscelis papua) and a coincident decrease in ice‐obligate Adélie penguins (P. adeliae) near Palmer Station, Anvers Island, WAP. Ecologically similar species that share a limited prey resource must occupy disparate foraging niches in order to co‐exist. Therefore, we determined the extent of foraging and dietary niche segregation between Adélie and gentoo penguins during the austral breeding season near Palmer Station. This research was conducted across six breeding seasons, from 2009 to 2014, which allowed us to investigate niche overlap in the context of interannual resource variability. Using biotelemetry and diet sampling, we found substantial overlap in the diets of Adélie and gentoo penguins, who primarily consumed Antarctic krill (Euphausia superba); however, our results showed that Adélie and gentoo penguins partitioned this shared prey resource through horizontal segregation of their core foraging areas. We did not find evidence that Antarctic krill were a limiting resource during the breeding season or that climate‐induced sympatry of Adélie and gentoo penguins resulted in competition for prey or caused the subsequent differing population trajectories. This apparent absence of resource competition between Adélie and gentoo penguins throughout this study implies that current population trends in this region are governed by other biological and physical factors. Our results highlight the importance of understanding the mechanistic processes that influence top predator populations in the context of climate‐driven ecosystem shifts. In this study, we investigated foraging and dietary niche partitioning between two recently sympatric Pygoscelis penguin populations on the West Antarctic Peninsula. We did not find evidence that climate‐induced sympatry in this scenario resulted in competitive exclusion. The results of this study provide important and timely insight into the underlying mechanistic processes driving penguin population changes in the Southern Ocean. [ABSTRACT FROM AUTHOR]

Abstract: Variation in the phenology of avian taxa has long been studied to understand how a species reacts to environmental changes over both space and time. Penguins (Sphenicidae) serve as an important example of how biotic and abiotic factors influence certain stages of seabird phenology because of their large ranges and the extreme, dynamic conditions present in their Southern Ocean habitats. Here, we examined the phenology of gentoo (Pygoscelis papua) and chinstrap penguins (Pygoscelis antarctica) at 17 sites across the Scotia arc, including the first documented monitoring of phenology on the South Sandwich Islands, to determine which breeding phases are intrinsic, or rather vary across a species range and between years. We used a novel method to measure seabird breeding phenology and egg and chick survival: time‐lapse cameras. Contrary to the long‐standing theory that these phases are consistent between colonies, we found that latitude and season had a predominant influence on the length of the nest establishment, incubation, and guard durations. We observe a trend toward longer incubation times occurring farther south, where ambient temperatures are colder, which may indicate that exposure to cold slows embryo growth. Across species, in colonies located farther south, parents abandoned nests later when eggs were lost or chicks died and the latest record of eggs or chicks in the nest occurred earlier during the breeding period. The variation in both space and time observed in penguin phenology provides evidence that the duration of phases within the annual cycle of birds is not fundamental, or genetic, as previously understood. Additionally, the recorded phenology dates should inform field researchers on the best timing to count colonies at the peak of breeding, which is poorly understood. [ABSTRACT FROM AUTHOR]

Abstract: Evaluating the fitness of organisms is an essential step towards understanding their responses to environmental change. Connections between energy expenditure and fitness have been postulated for nearly a century. However, testing this premise among wild animals is constrained by difficulties in measuring energy expenditure while simultaneously monitoring conventional fitness metrics such as survival and reproductive output. We addressed this issue by exploring the functional links between field metabolic rate (FMR), body condition, sex, age and reproductive performance in a wild population. We deployed 3D accelerometers on 115 Adélie penguins Pygoscelis adeliae during four breeding seasons at one of the largest colonies of this species, Cape Crozier, on Ross Island, Antarctica. The demography of this population has been studied for the past 18 years. From accelerometry recordings, collected for birds of known age and breeding history, we determined the vector of the dynamic body acceleration (VeDBA) and used it as a proxy for FMR. This allowed us to demonstrate relationships among FMR, a breeding quality index (BQI) and body condition. Notably, we found a significant quadratic relationship between mean VeDBA during foraging and BQI for experienced breeders, and individuals in better body condition showed lower rates of energy expenditure. We conclude that using FMR as a fitness component complementary to more conventional fitness metrics will yield greater understanding of evolutionary and conservation physiology. A plain language summary is available for this article. [ABSTRACT FROM AUTHOR]

The population history of the Adélie penguin ( Pygoscelis adeliae ) and its response to climatic and environmental changes have been widely studied in maritime Antarctica and several glacial refugia of Adélie penguins were dated back to the Last Glacial Maximum. However, the process of colony expansion during the subsequent glacial-interglacial transition was less well-documented. In this paper, we investigate an ornithogenic core from Vestfold Hills, East Antarctica, to improve knowledge of postglacial penguin colonization. Local deglaciation occurred around 15.6 kyr BP, based on a coarse-grained detrital layer, a date that is earlier than most of those reported in other studies from the same region. Geochemical analysis of the core suggests penguins started colonizing the northern Vestfold Hills around 14.6 kyr BP, the oldest geological record in East Antarctica on penguin occupation, and their population exhibited a broadly increasing trend thereafter. The population expanded at approximately 6740 yr BP, in the mid-Holocene, which corresponds to a local climatic optimum. Although this inference is based on population changes of local sub-colonies, it corresponds well to reconstructions of regional climate change, and changes in the penguin population based on genetic studies. From a consideration of the results of previous studies of the occupation history of sea birds following deglaciation in the Arctic, as well as other parts of Antarctica, we propose that sea birds colonized the emerging ice-free areas shortly after local glacier retreat. Over geological time-scales, the availability of breeding habitat is a key factor controlling the population size and activity range of Antarctic Adélie penguins. [ABSTRACT FROM AUTHOR]

The identification and quantification of Antarctic Pygoscelis penguin colonies depends increasingly on recognition of the characteristic optical properties of guano deposits, but almost all knowledge of these properties until now has been compromised by resolution and atmospheric propagation effects. Here we present hyperspectral reflectance data in the range 350–2500 nm, collected in situ from fresh guano deposits in Pygoscelis penguin colonies on Signy Island, South Orkney Islands. The period of data collection included the transition from predominantly white guano to the pink coloration characteristic of a krill-rich diet. The main identifiable features in the spectra are a broad absorption feature centred around 550 nm, responsible for the pink coloration and identified with the pigment astaxanthin, as well as several water absorption features. Variations in these features are responsible for differentiation between spectra. From these results we propose two spectral indices suitable for use with satellite data, one of which responds to the presence of astaxanthin in the guano and the other to water. Our results do not allow us to differentiate between penguin species from their guano, but do suggest that the breeding phenology of Pygoscelis penguins could be determined from a time series of multispectral imagery. [ABSTRACT FROM PUBLISHER]

Background: Foraging efficiency determines whether animals will be able to raise healthy broods, maintain their own condition, avoid predators and ultimately increase their fitness. Using accelerometers and GPS loggers, features of the habitat and the way animals deal with variable conditions can be translated into energetic costs of movement, which, in turn, can be translated to energy landscapes.We investigated energy landscapes in Gentoo Penguins Pygoscelis papua from two colonies at New Island, Falkland/Malvinas Islands. Results: In our study, the marine areas used by the penguins, parameters of dive depth and the proportion of pelagic and benthic dives varied both between years and colonies. As a consequence, the energy landscapes also varied between the years, and we discuss how this was related to differences in food availability, which were also reflected in differences in carbon and nitrogen stable isotope values and isotopic niche metrics. In the second year, the energy landscape was characterized by lower foraging costs per energy gain, and breeding success was also higher in this year. Additionally, an area around three South American Fur Seal Arctocephalus australis colonies was never used. Conclusions: These results confirm that energy landscapes vary in time and that the seabirds forage in areas of the energy landscapes that result in minimized energetic costs. Thus, our results support the view of energy landscapes and fear of predation as mechanisms underlying animal foraging behaviour. Furthermore, we show that energy landscapes are useful in linking energy gain and variable energy costs of foraging to breeding success. [ABSTRACT FROM AUTHOR]

Penguins are classified in the order Sphenisciformes into a single family, Spheniscidae. The genus Pygoscelis Wagler, 1832, is composed of three species, Pygoscelis antarcticus Forster, 1781, P. papua Forster, 1781 and P. adeliae Hombron & Jacquinot, 1841. In this work, the objective was to describe and to compare the karyotypes of Pygoscelis penguins contributing genetic information to Sphenisciformes. The metaphases were obtained by lymphocyte culture, and the diploid number and the C-banding pattern were determined. P. antarcticus has 2n = 92, P. papua 2n = 94 and P. adeliae exhibited 2n = 96 in males and 2n = 95 in females. The difference of diploid number in P. adeliae was identified as a multiple sex chromosome system where males have Z1Z1Z2Z2 and females Z1Z2W. The C-banding showed the presence of a heterochromatic block in the long arm of W chromosome and Z2 was almost entirely heterochromatic. The probable origin of a multiple system in P. adeliae was a translocation involving the W chromosome and the chromosome ancestral to Z2. The comparison made possible the identification of a high karyotype homology in Sphenisciformes which can be seen in the conservation of macrochromosomes and in the Z chromosome. The karyotypic divergences in Pygoscelis are restricted to the number of microchromosomes and W, which proved to be highly variable in size and morphology. The data presented in this work corroborate molecular phylogenetic proposals, supporting the monophyletic origin of penguins and intraspecific relations. [ABSTRACT FROM AUTHOR]

Past research during the breeding season in the Antarctic Peninsula region indicates that gentoo penguins ( Pygoscelis papua) are generalist foragers whereas Adélie ( P. adeliae) and chinstrap ( P. antarcticus) penguins tend to specialize on Antarctic krill ( Euphausia superba). However, little is known about the degree of temporal consistency in the diets and foraging habitats of these three species, particularly at the individual level. Such year-round and inter-annual dietary understanding is important to help interpret contrasting trends in their populations. We used carbon and nitrogen stable isotope analysis of blood and feathers to evaluate seasonal shifts in diet and individual foraging consistency within Pygoscelis penguin species breeding in the South Shetland Islands as well as among three geographically distinct gentoo penguin populations in the western Antarctic Peninsula and South Shetland Islands. We found that gentoo penguins exhibited a generalist foraging strategy with individual consistency, Adélie penguins exhibited an intermediate generalist foraging strategy with little individual consistency, and chinstrap penguins exhibited a specialized diet with little inter-individual variation. Our results also indicated that all three species have greater variation in foraging habitat use during the post-breeding season compared to the breeding season. Finally, we observed differences in the degree of seasonal shifts in population level diet and consistency in foraging strategies at the individual level across the three gentoo penguin populations examined. This suggests that Pygoscelis penguins can differ in diets and foraging habitat use not only at the population level among species, sites, and seasons, but also in the level of variation within populations, and in the degree of seasonal consistency among individuals. [ABSTRACT FROM AUTHOR]

Several studies have suggested that penguins are undergoing a major restructuring of their feeding habits and distribution after drastic climatic changes in the Antarctic Peninsula region. With the objective of estimating potential medium-term and inter-annual variations in trophic niche, we measured δ N and δ C in feather samples of pygoscelid penguins from museum specimens (1982-1984) and in blood and feather samples from 2009/10-2011 collected from animals on Ardley Island. Current penguin feathers had lower δ C and δ N values and were more similar to Antarctic krill values, than feathers in 1982-1984 and blood from 2009/10-2011. Moreover, δ C and δ N values from museum feathers and modern samples occupied a larger isotopic space in Gentoo Penguins ( Pygoscelis papua), compared to Adélie Penguins ( Pygoscelis adeliae) and Chinstrap Penguins ( Pygoscelis antarctica). Our results from feathers samples indicated that penguins have decreased their consumption of fish and other prey of higher trophic levels in the early interbreeding period (EIBP), while increasing the amount of euphausiids (Antarctic krill Euphausia superba) taken. The isotopic values of the species suggest that foraging sites varied significantly over time and seasonally. We suggest that environmental changes may have modified the feeding habits of pygoscelid penguins, resulting in changed foraging behaviour in the EIBP, and altering the secondary prey consumption. Prey choice in breeding pygoscelid species is probably limited by the foraging range around the breeding colony and competitive exclusion between congeners. [ABSTRACT FROM AUTHOR]

The presence of Campylobacter species was studied in three Antarctic penguin species, Adélie ( Pygoscelis adeliae), chinstrap ( Pygoscelis antarctica) and gentoo ( Pygoscelis papua). A total of 390 penguins were captured in 12 different rookeries along the Antarctic Peninsula with differences in the amount of human visitation: six colonies were highly visited [Stranger Point, King George Island ( P. papua and P. adeliae); Hannah Point, Livingston Island ( P. papua and P. antarctica); Deception Island ( P. antarctica); and Paradise Bay, Antarctic Peninsula ( P. papua)], and six colonies were rarely visited [Devil's Point, Byers Peninsula, Livingston Island ( P. papua); Cierva Cove, Antarctic Peninsula ( P. papua); Rongé Island ( P. papua and P. antarctica); Yalour Island ( P. adeliae); and Avian Island ( P. adeliae)]. A total of 23 strains were isolated from penguins from nine different rookeries. Campylobacter lari subsp. lari was isolated from eight samples (seven from P. papua and one from P. adeliae); C. lari subsp. concheus from 13 (ten from P. adeliae and three from P. antarctica) and C. volucris from two samples (both from P. papua). We did not find any significant differences in the prevalence of Campylobacter spp. between the populations in highly and rarely visited areas. This is the first report of C. lari subsp. concheus and C. volucris isolation from penguins in the Antarctic region. [ABSTRACT FROM AUTHOR]