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1
Stor, Thaís, Ginger A. Rebstock, Pablo García Borboroglu, and P. Dee Boersma. "Lateralization (handedness) in Magellanic penguins." PeerJ 7 (May 20, 2019): e6936. http://dx.doi.org/10.7717/peerj.6936.
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Lateralization, or asymmetry in form and/or function, is found in many animal species. Brain lateralization is considered adaptive for an individual, and often results in “handedness,” “footedness,” or a side preference, manifest in behavior and morphology. We tested for lateralization in several behaviors in a wild population of Magellanic penguins Spheniscus magellanicus breeding at Punta Tombo, Argentina. We found no preferred foot in the population (each penguin observed once) in stepping up onto an obstacle: 53% stepped up with the right foot, 47% with the left foot (n = 300, binomial test p = 0.27). We found mixed evidence for a dominant foot when a penguin extended a foot for thermoregulation, possibly depending on the ambient temperature (each penguin observed once). Penguins extended the right foot twice as often as the left foot (n = 121, p < 0.0005) in 2 years when we concentrated our effort during the heat of the day. In a third year when we observed penguins early and late in the day, there was no preference (n = 232, p = 0.59). Penguins use their flippers for swimming, including searching for and chasing prey. We found morphological evidence of a dominant flipper in individual adults: 60.5% of sternum keels curved one direction or the other (n = 76 sterna from carcasses), and 11% of penguins had more feather wear on one flipper than the other (n = 1217). Right-flippered and left-flippered penguins were equally likely in both samples (keels: p = 0.88, feather wear: p = 0.26), indicating individual but not population lateralization. In fights, aggressive penguins used their left eyes preferentially, consistent with the right side of the brain controlling aggression. Penguins that recently fought (each penguin observed once) were twice as likely to have blood only on the right side of the face (69%) as only on the left side (31%, n = 175, p < 0.001). The proportion of penguins with blood only on the right side increased with the amount of blood. In most fights, the more aggressive penguin used its left eye and attacked the other penguin’s right side. Lateralization depended on the behavior tested and, in thermoregulation, likely on the temperature. We found no lateralization or mixed results in the population of Magellanic penguins in three individual behaviors, stepping up, swimming, and thermoregulation. We found lateralization in the population in the social behavior fighting.
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Lenin, Kanagasabai. "Diminution of real power loss by novel gentoo penguin algorithm." International Journal of Informatics and Communication Technology (IJ-ICT) 9, no. 3 (December 1, 2020): 151. http://dx.doi.org/10.11591/ijict.v9i3.pp151-156.
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<span lang="EN-US">In this paper Gentoo Penguin Algorithm (GPA) is proposed to solve optimal reactive power problem. Gentoo Penguins preliminary population possesses heat radiation and magnetizes each other by absorption coefficient. Gentoo Penguins will move towards further penguins which possesses low cost (elevated heat concentration) of absorption. Cost is defined by the heat concentration, distance. Gentoo Penguins penguin attraction value is calculated by the amount of heat prevailed between two Gentoo penguins. Gentoo Penguins heat radiation is measured as linear. Less heat is received in longer distance, in little distance, huge heat is received. Gentoo Penguin Algorithm has been tested in standard IEEE 57 bus test system and simulation results show the projected algorithm reduced the real power loss considerably.</span>
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AINLEY, DAVID G., GRANT BALLARD, BRIAN J. KARL, and KATIE M. DUGGER. "Leopard seal predation rates at penguin colonies of different size." Antarctic Science 17, no. 3 (August 17, 2005): 335–40. http://dx.doi.org/10.1017/s0954102005002750.
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In a study designed to elucidate the factors that might differentially affect the well being and biology of Adélie penguins (Pygoscelis adeliae) that breed in colonies of different size, we investigated the predation rates on penguins by leopard seals (Hydrurga leptonyx) over a period of six years. The study colonies varied in size across the full range for this penguin species, contrasting with previous studies in which data were gathered only at very large colonies, and only in single years. The number of seals present varied directly with the amount of penguin traffic in the areas near the beach, where most predation takes place. Seals were present persistently only when penguin traffic exceeded about 250 penguins per hour. Predation rates also varied with penguin traffic in a curvilinear fashion, leveling off where traffic exceeded about 1200 penguins per hour. With respect to predation, it appears to be advantageous for Adélie penguins to nest in very small or very large colonies. At large colonies, the number of penguins moving to and from the colony ‘swamp’ the seals' predatory efforts, thus reducing the chances that an individual penguin will be taken. Small colonies are of little interest to the seals.
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Zeng, Yin-Xin, Hui-Rong Li, Wei Han, and Wei Luo. "Comparison of Gut Microbiota between Gentoo and Adélie Penguins Breeding Sympatrically on Antarctic Ardley Island as Revealed by Fecal DNA Sequencing." Diversity 13, no. 10 (October 15, 2021): 500. http://dx.doi.org/10.3390/d13100500.
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There are two pygoscelid penguins, the Gentoo (Pygoscelis papua Forster, 1781) and Adélie (P. adeliae Hombron and Jacquinot, 1841) penguins, breeding sympatrically on Ardley Island, Fildes Peninsula region, South Shetlands, Antarctica. Whether the two closely related penguin species with similar dietary habits possess compositional similarity in gut microbiota remains unknown. DNA barcoding of feces is an emerging approach for gut microbiota analysis of protected animals. In the present study, the 16S rRNA gene from penguin feces was sequenced using the Illumina MiSeq platform to investigate the gut microbiota of the two pygoscelid penguin species. The fecal community of Gentoo penguins has higher diversity indices and OTU (operational taxonomic unit) richness compared to Adélie penguins. Besides unclassified bacteria, sequences fell into 22 major lineages of the domain Bacteria: Acidobacteria, Actinobacteria, Armatimonadetes, Bacteroidetes, Chlamydiae, Chloroflexi, Cloacimonetes, Cyanobacteria, Deinococcus-Thermus, Fibrobacteres, Firmicutes, Fusobacteria, Gemmatimonadetes, Ignavibacteriae, Planctomycetes, Proteobacteria, Tenericutes, Verrucomicrobia, and candidate divisions BRC1, SR1, WPS-2, and Saccharibacteria. Among these, Firmicutes (37.7%), Proteobacteria (23.1%, mainly Gamma- and Betaproteobacteria), Fusobacteria (14.3%), Bacteroidetes (7.9%), and Actinobacteria (6.6%) were dominant in the fecal microbiota of the two penguin species. At the same time, significantly higher abundances of Actinobacteria and Cyanobacteria were detected in Gentoo penguins than in Adélie penguins (p < 0.05). Overall, there was a clear difference in the composition of gut microbiota between the Adélie and Gentoo penguins. The results suggested that both the phylogeny of penguin species and the diet could be responsible for the differences in the gut microbiota of the two pygoscelid penguins breeding in the same area.
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Williams, Cassondra L., Julie C. Hagelin, and Gerald L. Kooyman. "Hidden keys to survival: the type, density, pattern and functional role of emperor penguin body feathers." Proceedings of the Royal Society B: Biological Sciences 282, no. 1817 (October 22, 2015): 20152033. http://dx.doi.org/10.1098/rspb.2015.2033.
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Antarctic penguins survive some of the harshest conditions on the planet. Emperor penguins breed on the sea ice where temperatures drop below −40°C and forage in −1.8°C waters. Their ability to maintain 38°C body temperature in these conditions is due in large part to their feathered coat. Penguins have been reported to have the highest contour feather density of any bird, and both filoplumes and plumules (downy feathers) are reported absent in penguins. In studies modelling the heat transfer properties and the potential biomimetic applications of penguin plumage design, the insulative properties of penguin plumage have been attributed to the single afterfeather attached to contour feathers. This attribution of the afterfeather as the sole insulation component has been repeated in subsequent studies. Our results demonstrate the presence of both plumules and filoplumes in the penguin body plumage. The downy plumules are four times denser than afterfeathers and play a key, previously overlooked role in penguin survival. Our study also does not support the report that emperor penguins have the highest contour feather density.
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O’Brien, Shannon L., and Katherine A. Cronin. "The Impacts of a Commercial Bubble Curtain on Zoo-Housed African Penguin (Spheniscus demersus) Swimming Behavior." Journal of Zoological and Botanical Gardens 4, no. 3 (August 16, 2023): 567–77. http://dx.doi.org/10.3390/jzbg4030040.
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Swimming is an important behavior for all penguin species. However, zoo-housed penguins typically do not swim as often as their wild counterparts, which may have consequences for their health and welfare. In an effort to increase the swimming time of the African penguin (Spheniscus demersus) population at Lincoln Park Zoo in Chicago, IL, USA (21 adults: 13 males, 8 females), we introduced a commercially available bubble curtain to the outdoor pool within the penguins’ habitat. The bubble curtain pushes pressurized air out through a hose fitted with small holes to create a stream of bubbles that generate water movement, which could entice penguins to swim. Over the course of 2 months, the penguins were exposed to a series of alternating conditions characterized by the bubble curtain being off or on for 2-week periods. A total of 228 swimming bouts were observed during this study. The bubble curtain did not increase the amount of time the penguins spent swimming, nor the maximum number of penguins in the pool during swim bouts. Rather, the penguins spent more time swimming when the bubble curtain was turned off, and the number of penguins in the pool during swim bouts was consistent across experimental phases. Additionally, we found that penguins swam the most when air temperatures were between 31 and 40 °F (approximately −1 to −4 °C). Unexpectedly, at least three individual penguins swam overnight between the hours of midnight and 6:00, highlighting the value of monitoring animals during entire 24 h periods. Collectively, this study provides detailed information about the swimming behavior of a zoo-housed African penguin population, and indicates that a bubble curtain was ineffective at stimulating swimming.
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Huang, Tao, Liguang Sun, Yuhong Wang, and Renbin Zhu. "Penguin occupation in the Vestfold Hills." Antarctic Science 21, no. 2 (November 12, 2008): 131–34. http://dx.doi.org/10.1017/s095410200800165x.
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AbstractDuring CHINARE-22 (December 2005–March 2006), we investigated six penguin colonies in the Vestfold Hills, East Antarctica, and collected several penguin ornithogenic sediment cores, samples of fresh guano and modern penguin bone and feather. We selected seven penguin bones and feathers and six sediments from the longest sediment core and performed AMS14C dating. The results indicate that penguins occupied the Vestfold Hills as early as 8500 calibrated years before present (cal. yrbp), following local deglaciation and the formation of the ice free area. This is the first report on the Holocene history of penguins in the Vestfold Hills. As in other areas of Antarctica, penguins occupied this area as soon as local ice retreated and the ice free area formed, and they are very sensitive to climatic and environmental changes. This work provides the foundation for understanding the history of penguins occupation in Vestfold Hills, East Antarctica.
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Banks, Jonathan C., and Adrian M. Paterson. "A penguin-chewing louse (Insecta : Phthiraptera) phylogeny derived from morphology." Invertebrate Systematics 18, no. 1 (2004): 89. http://dx.doi.org/10.1071/is03022.
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Penguins are parasitised by 15 species of lice in the genera Austrogoniodes and Nesiotinus and present an opportunity to analyse phylogenetic relationships of two complete genera of chewing lice parasitising a monophyletic group of hosts. Taxonomy of penguin lice has been revised several times, including the erection of the genus Cesareus to contain some of the penguin-chewing louse species. Additionally, other groups of species within Austrogoniodes have been proposed. We constructed a phylogeny for all the chewing lice parasitising penguins from 46 parsimony-informative morphological characters and found support for two groups within Austrogoniodes, but little support for the Cesareus genus. Austrogoniodes metoecus, the only Austrogoniodes species parasitising a bird other than a penguin, was basal in the phylogeny, which suggests that if A. metoecus did originate from a louse species parasitising penguins, the host-switching event was unlikely to have been recent. A�superficial comparison of louse and penguin phylogenies identified some potential instances of co-speciation. However, a full analysis of co-phylogenetic relationships between penguins and their lice awaits the publication of a better-resolved penguin phylogeny.
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Chen, Cheng, Sheng-bo Yu, Yan-yan Chi, Guang-yuan Tan, Bao-cheng Yan, Nan Zheng, and Hong-Jin Sui. "Existence and features of the myodural bridge in Gentoo penguins: A morphological study." PLOS ONE 16, no. 4 (April 8, 2021): e0244774. http://dx.doi.org/10.1371/journal.pone.0244774.
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Recent studies have evidenced that the anatomical structure now known as the myodural bridge (MDB) connects the suboccipital musculature to the cervical spinal dura mater (SDM). In humans, the MDB passes through both the posterior atlanto-occipital and the posterior atlanto-axial interspaces. The existence of the MDB in various mammals, including flying birds (Rock pigeons and Gallus domesticus) has been previously validated. Gentoo penguins are marine birds, able to make 450 dives per day, reaching depths of up to 660 feet. While foraging, this penguin is able to reach speeds of up to 22 miles per hour. Gentoo penguins are also the world’s fastest diving birds. The present study was therefore carried out to investigate the existence and characteristics of the MDB in Gentoo penguin (Pygoscelis papua), a non-flying, marine bird that can dive. For this study, six Gentoo penguin specimens were dissected to observe the existence and composition of their MDB. Histological staining was also performed to analyze the anatomic relationships and characteristic of the MDB in the Gentoo penguin. In this study, it was found that the suboccipital musculature in the Gentoo penguin consists of the rectus capitis dorsalis minor (RCDmi) muscle and rectus capitis dorsalis major (RCDma) muscle. Dense connective tissue fibers were observed connecting these two suboccipital muscles to the spinal dura mater (SDM). This dense connective tissue bridge consists of primarily type I collagen fibers. Thus, this penguin’s MDB appears to be analogous to the MDB previously observed in humans. The present study evidences that the MDB not only exists in penguins but it also has unique features that distinguishes it from that of flying birds. Thus, this study advances the understanding of the morphological characteristics of the MDB in flightless, marine birds.
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Kerley, Graham I. H., and Theuns Erasmus. "THE MANAGEMENT OF OILED PENGUINS." International Oil Spill Conference Proceedings 1987, no. 1 (April 1, 1987): 465–68. http://dx.doi.org/10.7901/2169-3358-1987-1-465.
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ABSTRACT As highly aquatic animals, penguins are particularly vulnerable to oil pollution. Penguins are increasingly often exposed to oil pollution, and the jackass penguin, Spheniscus demersus, endemic to southern Africa, may be the penguin species most exposed. The main effects of oiling on penguins are loss of the waterproofing and insulative properties of the feathers. Oiled penguins are capable of thermoregulation in air, but within 5 min become hypothermic in water (despite significantly increased heat production), and must retreat to land or die from hypothermia. Oiled penguins are therefore prevented from going to sea to forage, and die of starvation without assistance. Oiled penguins in captivity show a temporary loss of appetite (for about 5 days) but are capable of utilizing food and recover body-weight rapidly. In cleaning and rehabilitating oiled penguins it is necessary to remove all the oil as well as other contaminants on the feathers to ensure waterproofness of the feathers. Cleaning techniques have been developed so that it is now possible to clean and waterproof oiled penguins in less than an hour, reducing the total time for rehabilitation (allowing the generally emaciated birds to recover body weight) to 12.2 days (n = 84), a significant improvement over older techniques. Cleaning has been shown to be a workable treatment for oiled jackass penguins, with proven breeding success after cleaning. Recommendations relevant to the management of oiled penguins are presented.
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Cole, Theresa L., Daniel T. Ksepka, Kieren J. Mitchell, Alan J. D. Tennyson, Daniel B. Thomas, Hailin Pan, Guojie Zhang, et al. "Mitogenomes Uncover Extinct Penguin Taxa and Reveal Island Formation as a Key Driver of Speciation." Molecular Biology and Evolution 36, no. 4 (February 5, 2019): 784–97. http://dx.doi.org/10.1093/molbev/msz017.
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Abstract The emergence of islands has been linked to spectacular radiations of diverse organisms. Although penguins spend much of their lives at sea, they rely on land for nesting, and a high proportion of extant species are endemic to geologically young islands. Islands may thus have been crucial to the evolutionary diversification of penguins. We test this hypothesis using a fossil-calibrated phylogeny of mitochondrial genomes (mitogenomes) from all extant and recently extinct penguin taxa. Our temporal analysis demonstrates that numerous recent island-endemic penguin taxa diverged following the formation of their islands during the Plio-Pleistocene, including the Galápagos (Galápagos Islands), northern rockhopper (Gough Island), erect-crested (Antipodes Islands), Snares crested (Snares) and royal (Macquarie Island) penguins. Our analysis also reveals two new recently extinct island-endemic penguin taxa from New Zealand’s Chatham Islands: Eudyptes warhami sp. nov. and a dwarf subspecies of the yellow-eyed penguin, Megadyptes antipodes richdalei ssp. nov. Eudyptes warhami diverged from the Antipodes Islands erect-crested penguin between 1.1 and 2.5 Ma, shortly after the emergence of the Chatham Islands (∼3 Ma). This new finding of recently evolved taxa on this young archipelago provides further evidence that the radiation of penguins over the last 5 Ma has been linked to island emergence. Mitogenomic analyses of all penguin species, and the discovery of two new extinct penguin taxa, highlight the importance of island formation in the diversification of penguins, as well as the extent to which anthropogenic extinctions have affected island-endemic taxa across the Southern Hemisphere’s isolated archipelagos.
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Roberts, Laura C., Umberto Molini, Lauren M. Coetzee, Siegfried Khaiseb, Jean-Paul Roux, Jessica Kemper, David G. Roberts, et al. "Is Penguin Circovirus Circulating Only in the Antarctic Circle? Lack of Viral Detection in Namibia." Animals 13, no. 9 (April 24, 2023): 1449. http://dx.doi.org/10.3390/ani13091449.
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The known host range of circoviruses is continuously expanding because of more intensive diagnostic activities and advanced sequencing tools. Recently, a new circovirus (penguin circovirus (PenCV)) was identified in the guano and cloacal samples collected from Adélie penguins (Pygoscelis adeliae) and chinstrap penguins (Pygoscelis antarcticus) in Antarctica. Although the virus was detected in several asymptomatic subjects, a potential association with feather disease was speculated. To investigate the occurrence and implications of PenCV in other penguin species located outside of Antarctica, a broad survey was undertaken in African penguins (Spheniscus demersus) on two islands off the southern Namibian coast. For this purpose, specific molecular biology assays were developed and validated. None of the 151 blood samples tested positive for PenCV. Several reasons could explain the lack of PenCV positive samples. African penguins and Pygoscelis species are separated by approximately 6000 km, so there is almost no opportunity for transmission. Similarly, host susceptibility to PenCV might be penguin genus-specific. Overall, the present study found no evidence of PenCV in African penguin colonies in Namibia. Further dedicated studies are required to assess the relevance of PenCV among different penguin species.
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Levinson, Parker M., Annie E. Schmidt, Virginia Morandini, Megan Elrod, Dennis Jongsomjit, and Grant Ballard. "Breeding behaviour of colour-aberrant Adélie penguins (Pygoscelis adeliae) at Cape Crozier, Ross Island, Antarctica." Antarctic Science 33, no. 4 (May 18, 2021): 335–43. http://dx.doi.org/10.1017/s0954102021000158.
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AbstractPlumage colour variation occurs widely among bird species and is often associated with individual fitness. More specifically, colouration can affect thermoregulatory ability, mate selection and conspicuousness during foraging. Colour aberrations can be caused by genetic mutations, dietary imbalances, environmental conditions or disease and are rare. Plumage variations have previously been noted in Adélie penguins, although without any follow-up to measure implications for behaviour or fitness. To assess how this low-frequency condition affects breeding in Adélie penguins, we monitored the breeding of several colour-aberrant Adélie penguins during the 2019–2020 nesting season at the large Cape Crozier, Ross Island colony (> 300,000 pairs). In total, we found 12 individuals with unusual plumage for a frequency of 1:50,000 breeding penguins. There were seven dark brown Adélie penguins, three progressive greying Adélie penguins, one dilute Adélie penguin and one brown Adélie penguin, of which five were female, three male and four of unknown sex. Six colour aberrants initiated breeding with a normal-coloured mate, and five raised at least one chick to crèche. The likelihood of breeding and breeding success of colour aberrants were similar to those of normal-coloured Adélie penguins, suggesting that colour aberrations do not negatively affect breeding.
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Walker, Brian G., P. Dee Boersma, and John C. Wingfield. "The glucocorticoid stress response in Magellanic Penguins (Spheniscus magellanicus): comparing within and between breeding seasons, by age and colony, after fighting, and with other penguin species." Canadian Journal of Zoology 93, no. 2 (February 2015): 123–31. http://dx.doi.org/10.1139/cjz-2014-0216.
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Comparing baseline and stress-induced glucocorticoid hormone levels in animals is a popular tool to assess differences in stress experienced among groups. We compare corticosterone levels in Magellanic Penguins (Spheniscus magellanicus (J.R. Forster, 1781)) in situations where we hypothesize differences in stress patterns may exist. We compared penguins both within and between breeding seasons, birds breeding at two different locations, penguins at three different ages, penguins that had shown evidence of recent fighting, and, finally, how stress patterns differed for four different penguin species. Throughout a breeding season (settlement, incubation, and chick-rearing), we found no differences in either baseline or stress-induced hormone concentrations. Chick, juvenile, and adult penguins did not differ in baseline corticosterone levels, but juveniles had a reduced stress response. Penguins in one season showed a stress response to capture, likely due to a recent severe weather event. We found no differences in baseline or stress-induced hormone titers for birds from two different breeding locations. Evidence of recent fighting also did not alter baseline corticosterone levels. Finally, among four species of penguins measured (Magellanic, Humboldt (Spheniscus humboldti Meyen, 1834), Galápagos (Spheniscus mendiculus Sundevall, 1871), and Rockhopper (Eudyptes chrysocome (J.R. Forster, 1781)), baseline levels were always consistent, while stress-induced levels were significantly higher in the Rockhopper Penguin only.
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Thomas, Daniel B., Alan J. D. Tennyson, R. Paul Scofield, Tracy A. Heath, Walker Pett, and Daniel T. Ksepka. "Ancient crested penguin constrains timing of recruitment into seabird hotspot." Proceedings of the Royal Society B: Biological Sciences 287, no. 1932 (August 12, 2020): 20201497. http://dx.doi.org/10.1098/rspb.2020.1497.
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New Zealand is a globally significant hotspot for seabird diversity, but the sparse fossil record for most seabird lineages has impeded our understanding of how and when this hotspot developed. Here, we describe multiple exceptionally well-preserved specimens of a new species of penguin from tightly dated (3.36–3.06 Ma) Pliocene deposits in New Zealand. Bayesian and parsimony analyses place Eudyptes atatu sp. nov. as the sister species to all extant and recently extinct members of the crested penguin genus Eudyptes . The new species has a markedly more slender upper beak and mandible compared with other Eudyptes penguins. Our combined evidence approach reveals that deep bills evolved in both crested and stiff-tailed penguins ( Pygoscelis ) during the Pliocene. That deep bills arose so late in the greater than 60 million year evolutionary history of penguins suggests that dietary shifts may have occurred as wind-driven Pliocene upwelling radically restructured southern ocean ecosystems. Ancestral area reconstructions using BioGeoBEARS identify New Zealand as the most likely ancestral area for total-group penguins, crown penguins and crested penguins. Our analyses provide a timeframe for recruitment of crown penguins into the New Zealand avifauna, indicating this process began in the late Neogene and was completed via multiple waves of colonizing lineages.
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Saavedra, Casilda, and Taibah Alhatem. "Climate change effects on emperor penguins." Revista de Iniciación Científica 4, no. 2 (April 1, 2019): 57–60. http://dx.doi.org/10.33412/rev-ric.v4.2.2157.
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Climate change is one of the major issues affecting our mother Earth. The change in climate include both the change intemperature and the change in precipitation. Both of these parameters are very crucial to animals and plants where they depend onthem for their survival. Climate change has so many negative impacts on the biodiversity of the Earth especially in the Arctic andAntarctic continents. The rise in temperature decreases the ice coverage which in return reduces the population of the wildlife. Theice coverage is crucial to the biodiversity living in Antarctica where they depend on it for their survival. It’s very important for theirfeeding, breeding, and habitat. However, with the reduction of ice, many animals are becoming close to extinction. One of thosespecies that were negatively impacted by climate change is emperor penguins (Aptenodytes forsteri). These penguins require verylow temperatures in order to breed and populate. Very high temperatures for these penguins could result in decreased population ratearound Antarctica. An analysis was done of emperor penguin population data found in different research papers in conjunction withtemperature anomalies data in Antarctica from 1983 to 2005 from the National Oceanic and Atmospheric Administration (NOAA).The results indicated that there was an inverse relationship between the temperature and the penguin’s population. It was shownthrough the analysis conducted that the temperature impacted the penguins negatively throughout the years since the temperaturewas rising. It decreased their breeding population and chicks count dramatically in all the parts of Antarctica tested.
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Jafari, Vahideh, Deborah Maccapan, Giulio Careddu, Simona Sporta Caputi, Edoardo Calizza, Loreto Rossi, and Maria Letizia Costantini. "Spatial and temporal diet variability of Adélie (Pygoscelis adeliae) and Emperor (Aptenodytes forsteri) Penguin: a multi tissue stable isotope analysis." Polar Biology 44, no. 9 (August 10, 2021): 1869–81. http://dx.doi.org/10.1007/s00300-021-02925-1.
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AbstractThe Ross Sea, Antarctica, supports large populations of Emperor Penguin (Aptenodytes forsteri) and Adélie Penguin (Pygoscelis adeliae), two key meso-predators that occupy high trophic levels. Despite these species are largely studied, little is known about their diet outside the breeding period. In the present study, we investigated the intra-annual diet of Adélie and Emperor Penguins belonging to five colonies in the Ross Sea through the stable isotope analysis of different tissues (feathers and shell membranes), synthetized in different seasons, and guano that indicates recent diet. Penguin samples and prey (krill and fish) were collected during the Antarctic spring–summer. δ13C and δ15N of tissues and guano indicate spatio-temporal variation in the penguin diet. The krill consumption by Adélie Penguins was lowest in winter except in the northernmost colony, where it was always very high. It peaked in spring and remained prevalent in summer. The greatest krill contribution to Emperor Penguin’s diet occurred in summer. The relative krill and fish consumption by both species changed in relation to the prey availability, which is influenced by seasonal sea ice dynamics, and according to the penguin life cycle phases. The results highlight a strong trophic plasticity in the Adélie Penguin, whose dietary variability has been already recognized, and in the Emperor Penguin, which had not previously reported. Our findings can help understand how these species might react to resource variation due to climate change or anthropogenic overexploitation. Furthermore, data provides useful basis for future comparisons in the Ross Sea MPA and for planning conservation actions.
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Drabek, Charles M. "Heart and ventricle weights of Antarctic penguins." Canadian Journal of Zoology 67, no. 10 (October 1, 1989): 2602–4. http://dx.doi.org/10.1139/z89-367.
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The hearts of Emperor (Aptenodytes forsteri), Chinstrap (Pygoscelis antarctica), and Adelie penguins (Pygoscelis adeliae) were weighed and measured to elucidate morphological parameters that might be functional for diving. These heart parameters are the first to be described for penguins. Heart weights of both the Chinstrap (42.4 g) and Adelie penguins (37.5 g) were greater than predicted for birds of their body size. The weight of the right ventricle in proportion to both the heart and the left ventricle was significantly greater in the Emperor Penguin than in the Chinstrap and Adelie penguins.
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Subramanian, Sankar, Gabrielle Beans-Picón, Siva K. Swaminathan, Craig D. Millar, and David M. Lambert. "Evidence for a recent origin of penguins." Biology Letters 9, no. 6 (December 23, 2013): 20130748. http://dx.doi.org/10.1098/rsbl.2013.0748.
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Penguins are a remarkable group of birds, with the 18 extant species living in diverse climatic zones from the tropics to Antarctica. The timing of the origin of these extant penguins remains controversial. Previous studies based on DNA sequences and fossil records have suggested widely differing times for the origin of the group. This has given rise to widely differing biogeographic narratives about their evolution. To resolve this problem, we sequenced five introns from 11 species representing all genera of living penguins. Using these data and other available DNA sequences, together with the ages of multiple penguin fossils to calibrate the molecular clock, we estimated the age of the most recent common ancestor of extant penguins to be 20.4 Myr (17.0–23.8 Myr). This time is half of the previous estimates based on molecular sequence data. Our results suggest that most of the major groups of extant penguins diverged 11–16 Ma. This overlaps with the sharp decline in Antarctic temperatures that began approximately 12 Ma, suggesting a possible relationship between climate change and penguin evolution.
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Chen, Xintong, Jiquan Chen, Xiao Cheng, Lizhong Zhu, Bing Li, and Xianglan Li. "Retreating Shorelines as an Emerging Threat to Adélie Penguins on Inexpressible Island." Remote Sensing 13, no. 22 (November 22, 2021): 4718. http://dx.doi.org/10.3390/rs13224718.
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Long-term observation of penguin abundance and distribution may warn of changes in the Antarctic marine ecosystem and provide support for penguin conservation. We conducted an unmanned aerial vehicle (UAV) survey of the Adélie penguin (Pygoscelis adeliae) colony on Inexpressible Island and obtained aerial images with a resolution of 0.07 m in 2018. We estimated penguin abundance and identified the spatial extent of the penguin colony. A total of 24,497 breeding pairs were found on Inexpressible Island within a colony area of 57,507 m2. Based on historical images, the colony area expanded by 30,613 m2 and abundance increased by 4063 pairs between 1983 and 2012. Between 2012 and 2018 penguin abundance further increased by 3314 pairs, although the colony area decreased by 1903 m2. In general, Adélie penguins bred on Inexpressible Island at an elevation <20 m, and >55% of penguins had territories within 150 m of the shoreline. This suggests that penguins prefer to breed in areas with a low elevation and close to the shoreline. We observed a retreat of the shoreline on Inexpressible Island between 1983 and 2018, especially along the northern coast, which may have played a key role in the expansion of the penguin colony on the northern coast. In sum, it appears that retreating shorelines reshaped penguin distribution on the island and may be an emerging risk factor for penguins. These results highlight the importance of remote sensing techniques for monitoring changes in the Antarctic marine ecosystem and providing reliable data for Antarctic penguin conservation.
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Chiew, Samantha J., Kym L. Butler, Sally L. Sherwen, Grahame J. Coleman, Kerry V. Fanson, and Paul H. Hemsworth. "Effects of Regulating Visitor Viewing Proximity and the Intensity of Visitor Behaviour on Little Penguin (Eudyptula minor) Behaviour and Welfare." Animals 9, no. 6 (May 28, 2019): 285. http://dx.doi.org/10.3390/ani9060285.
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We examined the effects of regulating the viewing proximity of visitors and the intensity of visitor behaviour on behaviours indicative of fear and stress physiology of 15 zoo-housed little penguins (Eudyptula minor). A 2 × 2 factorial fully randomised design was used to examine the effects of regulating: (1) the viewing proximity of visitors to enclosure, ‘normal viewing distance’ and ’increased viewing distance’ (using a physical barrier set up 2 m away from the enclosure), and (2) the intensity of visitor behaviour, ‘unregulated visitor behaviour’ and ‘regulated visitor behaviour’ (using signage and uniformed personnel). In addition, a treatment consisting of closing the enclosure to visitors was included. Penguin behaviour, visitor numbers and visitor behaviour were recorded by CCTV video recordings and direct observations, respectively. Penguin faecal glucocorticoid metabolites were also analysed as a measure of stress physiology. We found that increased viewing distance reduced (p < 0.05) all visitor behaviours except for loud vocalisations and tactile contact with penguins. However, there were no direct effects of signage and uniformed personnel on visitor behaviour (p > 0.05). As the regulation of viewing proximity increased from a closed exhibit to an open exhibit with increased viewing distance, and then to an open exhibit with normal viewing distance, this increased the proportion of penguins huddling (p = 0.0011), vigilant (p = 0.0060) and retreating (p = 0.00013), and decreased the proportion of penguins within 1 m of the visitor viewing area (p = 0.00066), surface swimming (p = 0.00091) and preening in the water (p = 0.042). There were also limited effects of regulating visitor behaviour on penguin behaviour. No treatment effects were found on faecal glucocorticoid metabolites (p > 0.05). These results indicate that regulating visitor viewing proximity affects penguin behaviours indicative of fear and visitor behaviour. This suggests that close visitor contact can be fear-provoking for little penguins but increasing the distance between visitors and penguins can reduce fear responses of penguins by regulating both viewing proximity and visitor behaviour. However, it is unclear whether these changes in penguin behaviour are due to the increased separation between visitors and penguins and/or specific visitor behaviours associated with close viewing proximity to the enclosure, such as leaning over the enclosure or tactile contact with the pool, which are impeded when visitors are further away.
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Abad, F. Xavier, Núria Busquets, Azucena Sanchez, Peter G. Ryan, Natàlia Majó, and Jacob Gonzalez-Solís. "Serological and virological surveys of the influenza A viruses in Antarctic and sub-Antarctic penguins." Antarctic Science 25, no. 2 (March 20, 2013): 339–44. http://dx.doi.org/10.1017/s0954102012001228.
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AbstractTo evaluate the avian influenza virus (AIV) circulation in Antarctic and sub-Antarctic penguins we carried out a serosurvey on six species from Livingston, Marion and Gough islands. Seropositivity against AIV was performed on serum samples using a competitive enzyme-linked immunosorbent assay and haemagglutination and neuraminidase inhibition assays. Some oropharyngeal and cloacal swabs were also assayed to detect influenza virus genomes by real time reverse transcription-polymerase chain reaction. Overall, 12.1% (n= 140) penguins were seropositive to AIV. By species, we detected 5% (n= 19) and 11% (n= 18) seroprevalence in sub-Antarctic rockhopper penguins (Eudyptesspp.) from Gough and Marion islands, respectively, 42% (n= 33) seroprevalence in macaroni penguins (Eudyptes chysolophusBrandt), but no positives in the three other species, gentoo (Pygoscelis papuaForster;n= 25) and chinstrap penguins (P. antarcticaForster;n= 16), from Livingston Island and king penguins (Aptenodytes patagonicusMiller;n= 27) from Marion Island. While seropositivity reflected previous exposure to the AIV, the influenza genome was not detected. Our results indicate that AIV strains have circulated in penguin species in the sub-Antarctic region, but further studies are necessary to determine the precise role that such penguin species play in AIV epidemiology and if this circulation is species (or genus) specific.
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Levy, Hila, Steven R. Fiddaman, Anni Djurhuus, Caitlin E. Black, Simona Kraberger, Adrian L. Smith, Tom Hart, and Arvind Varsani. "Identification of Circovirus Genome in a Chinstrap Penguin (Pygoscelis antarcticus) and Adélie Penguin (Pygoscelis adeliae) on the Antarctic Peninsula." Viruses 12, no. 8 (August 6, 2020): 858. http://dx.doi.org/10.3390/v12080858.
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Circoviruses infect a variety of animal species and have small (~1.8–2.2 kb) circular single-stranded DNA genomes. Recently a penguin circovirus (PenCV) was identified associated with an Adélie Penguin (Pygoscelis adeliae) with feather disorder and in the cloacal swabs of three asymptomatic Adélie Penguins at Cape Crozier, Antarctica. A total of 75 cloacal swab samples obtained from adults and chicks of three species of penguin (genus: Pygoscelis) from seven Antarctic breeding colonies (South Shetland Islands and Western Antarctic Peninsula) in the 2015−2016 breeding season were screened for PenCV. We identified new variants of PenCV in one Adélie Penguin and one Chinstrap Penguin (Pygoscelis antarcticus) from Port Charcot, Booth Island, Western Antarctic Peninsula, a site home to all three species of Pygoscelid penguins. These two PenCV genomes (length of 1986 nucleotides) share > 99% genome-wide nucleotide identity with each other and share ~87% genome-wide nucleotide identity with the PenCV sequences described from Adélie Penguins at Cape Crozier ~4400 km away in East Antarctica. We did not find any evidence of recombination among PenCV sequences. This is the first report of PenCV in Chinstrap Penguins and the first detection outside of Ross Island, East Antarctica. Given the limited knowledge on Antarctic animal viral diversity, future samples from Antarctic wildlife should be screened for these and other viruses to determine the prevalence and potential impact of viral infections.
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Kowalczyk, Nicole D., André Chiaradia, Tiana J. Preston, and Richard D. Reina. "Fine-scale dietary changes between the breeding and non-breeding diet of a resident seabird." Royal Society Open Science 2, no. 4 (April 2015): 140291. http://dx.doi.org/10.1098/rsos.140291.
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Unlike migratory seabirds with wide foraging ranges, resident seabirds forage in a relatively small range year-round and are thus particularly vulnerable to local shifts in prey availability. In order to manage their populations effectively, it is necessary to identify their key prey across and within years. Here, stomach content and stable isotope analyses were used to reconstruct the diet and isotopic niche of the little penguin ( Eudyptula minor ). Across years, the diet of penguins was dominated by anchovy ( Engraulis australis ). Within years, during winter, penguins were consistently enriched in δ 15 N and δ 13 C levels relative to pre-moult penguins. This was probably due to their increased reliance on juvenile anchovies, which dominate prey biomass in winter months. Following winter and during breeding, the δ 13 C values of penguins declined. We suggest this subtle shift was in response to the increased consumption of prey that enter the bay from offshore regions to spawn. Our findings highlight that penguins have access to both juvenile fish communities and spawning migrants across the year, enabling these seabirds to remain in close proximity to their colony. However, annual fluctuations in penguin isotopic niche suggest that the recruitment success and abundance of fish communities fluctuate dramatically between years. As such, the continued monitoring of penguin diet will be central to their ongoing management.
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Hadden, Peter, Akilesh Gokul, Satya Amirapu, Ratish Kurian, Charles McGhee, and Jie Zhang. "Confocal and Electron Microscopic Structure of the Cornea from Three Species of Penguin." Vision 7, no. 1 (January 3, 2023): 4. http://dx.doi.org/10.3390/vision7010004.
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Corneal confocal microscopy has not previously been performed in penguins, despite recognition of its unusually flat shape. To identify features that the penguin shares with other birds and or mammals and those specific to penguins, we undertook confocal microscopic examination of two little (Eudyptula minor), four gentoo (Pygoscelis papua) and five king (Aptenodytes patagonicus) penguin corneas. Transmission electron microscopy was performed on one gentoo and one king penguin, for finer details. Features shared with other higher vertebrates included a five-layered cornea and a similar limbus. Typically avian were a lower density of stromal cells, a more regular arrangement of collagen bands and an absent basal nerve plexus. Features unique to penguins included a flattened superficial epithelium (king penguin), stromal myofibroblasts (all) and an irregular endothelium (little penguin). Other features uniquely identified by confocal microscopy in birds include epithelial and stromal nerves, guttata and stromal imprints on Descemet’s membrane. Transmission electron microscopy identified a lack of wing cells (king penguin), greater posterior collagen lamellae thickness (gentoo penguin) and significantly less interlacing of collagen lamellae in the central cornea (king and gentoo). Most of these unique features are yet to be explained, but some could be adaptations to diving.
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Klages, NTW, RP Gales, and D. Pemberton. "Dietary Segregation of Macaroni and Rockhopper Penguins at Heard Island." Wildlife Research 16, no. 6 (1989): 599. http://dx.doi.org/10.1071/wr9890599.
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This paper reports on the first quantitative study of the diet of macaroni and rockhopper penguins (Eudytes chrysolophus and E. chrysocome) undertaken on sub-Antarctic Heard Island. Stomach contents were sampled during the late incubation and early chick-rearing phase. Both penguin species generally fed on euphausiids and fish, albeit in different proportions and frequently on different species and sizes. In particular, macaroni penguins consumed considerably more fish on a per cent mass basis (23.2 v. 8.0%), selecting larger sized prey than rockhopper penguins did. It is hypothesised that these dietary differences provide macaroni penguins with a broader feeding niche leading to a greater availability of food and are thus an important factor contributing to the numerical dominance of macaroni penguins on the island.
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Golemansky, Vassil. "Coccidian parasites (Apicomplexa) of penguins (Pygoscelis ssp.) from Livingston Island and King George Island, the Antarctic." Polish Polar Research 32, no. 3 (January 1, 2011): 263–68. http://dx.doi.org/10.2478/v10183-011-0018-4.
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Coccidian parasites (Apicomplexa) of penguins (Pygoscelis ssp.) from Livingston Island and King George Island, the Antarctic The results of investigations on the coccidian parasites of three species of penguins (Pygoscelis antarctica, P. papua and P. adeliae), nesting at Livingston and King George Island (South Shetland Islands, the Antarctic) are presented. Three coccidian parasites: Eimeria pygosceli Golemansky, 2003, Eimeria sp. and Isospora sp. were identified in faecal samples from 360 examined birds. The total prevalence of coccidian parasites was high: about 35% in all of examined penguins. No host specificity was observed. It is attributed due to the close phylogenetic relations, common habitats and nesting territories, similar feeding and reproductive biology of the three penguin species. In more than 20 specimens of investigated penguins a high intensity of oocysts in their guano was observed (80-220 oocysts in one microscopic field at magnification of 150x) an indirect indication of the negative role of the coccidian infections on penguin populations.
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Gheraibia, Youcef, Abdelouahab Moussaoui, Sohag Kabir, and Smaine Mazouzi. "Pe-DFA." International Journal of Applied Metaheuristic Computing 7, no. 2 (April 2016): 58–70. http://dx.doi.org/10.4018/ijamc.2016040104.
Full textAbstract:
DNA Fragment Assembly (DFA) is a process of finding the best order and orientation of a set of DNA fragments to reconstruct the original DNA sequence from them. As it has to consider all possible combinations among the DNA fragments, it is considered as a combinatorial optimisation problem. This paper presents a method showing the use of Penguins Search Optimisation Algorithm (PeSOA) for DNA fragment assembly problem. Penguins search optimisation is a nature inspired metaheuristic algorithm based on the collaborative hunting strategy of penguins. The approach starts its operation by generating a set of random population. After that, the population is divided into several groups, and each group contains a set of active fragments in which the penguins concentrate on the search process. The search process of the penguin optimisation algorithm is controlled by the oxygen reserve of penguins. During the search process each penguin shares its best found solution with other penguins to quickly converge to the global optimum. In this paper, the authors adapted the original PeSOA algorithm to obtain a new algorithm structure for DNA assembly problem. The effectiveness of the proposed approach has been verified by applying it on the well-known benchmarks for the DNA assembly problem. The results show that the proposed method performed well compared to the most used DNA fragment assembly methods.
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Adams, N. J., C. Moloney, and R. Navarro. "Estimated food consumption by penguins at the Prince Edward Islands." Antarctic Science 5, no. 3 (September 1993): 245–52. http://dx.doi.org/10.1017/s0954102093000331.
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The consumption of food by the four species of breeding penguins at the Prince Edward Islands is assessed on an annual and seasonal basis. Total annual food consumption was estimated at 880 000 t, of which king penguins accounted for 74%, macaroni penguins 21%, rockhopper penguins 5% and gentoo penguins <1%. Pelagic fish, almost entirely myctophids, were the most important prey (70% of total prey biomass), followed by pelagic crustaceans (18%) and cephalopods (11%). Demersal fish and benthic crustaceans accounted for <1% of total consumption, being consumed only by gentoo penguins. Peak demands of between 2 and 3.3 × 106 kg d−1 occurred from October–December when three of the four species were breeding, including the two demi-populations of king penguins. Food demand decreased to 1.2 × 106 kg d−1 during winter when only king and gentoo penguins were present. Much of the prey are presumably captured within 300 km of the islands. Assuming an even distribution of foraging effort within their respective foraging ranges, rates of food transferred to penguins in November ranged from 4.1 × 10−3 g m−2 d−1 for macaroni penguins to 1.24 × 10−2 g m−2 d−1 for king penguins. In mid-July, transfer rates to king and gentoo penguins were 3.9 × 10−3 g m−2 d−1 and 6.7 × 10−3 g m−2 d−1, respectively. The importance of pelagic myctophid fish to penguin populations at the Prince Edward Islands is clear.
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Wu, Jiahui, Wen Xu, Jianfeng He, and Musheng Lan. "YOLO for Penguin Detection and Counting Based on Remote Sensing Images." Remote Sensing 15, no. 10 (May 16, 2023): 2598. http://dx.doi.org/10.3390/rs15102598.
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As the largest species of birds in Antarctica, penguins are called “biological indicators”. Changes in the environment will cause population fluctuations. Therefore, developing a penguin census regularly will not only help carry out conservation activities but also provides a basis for studying climate change. Traditionally, scholars often use indirect methods, e.g., identifying penguin guano and establishing regression relationships to estimate the size of penguin colonies. In this paper, we explore the feasibility of automatic object detection algorithms based on aerial images, which locate each penguin directly. We build a dataset consisting of images taken at 400 m altitude over the island populated by Adelie penguins, which are cropped with a resolution of 640 × 640. To address the challenges of detecting minuscule penguins (often 10 pixels extent) amidst complex backgrounds in our dataset, we propose a new object detection network, named YoloPd (Yolo for penguin detection). Specifically, a multiple frequency features fusion module and a Bottleneck aggregation layer are proposed to strengthen feature representations for smaller penguins. Furthermore, the Transformer aggregation layer and efficient attention module are designed to capture global features with the aim of filtering out background interference. With respect to the latency/accuracy trade-off, YoloPd surpasses the classical detector Faster R-CNN by 8.5% in mean precision (mAP). It also beats the latest detector Yolov7 by 2.3% in F1 score with fewer parameters. Under YoloPd, the average counting accuracy reaches 94.6%, which is quite promising. The results demonstrate the potential of automatic detectors and provide a new direction for penguin counting.
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Thomas, Daniel B., and R. Ewan Fordyce. "The heterothermic loophole exploited by penguins." Australian Journal of Zoology 55, no. 5 (2007): 317. http://dx.doi.org/10.1071/zo07053.
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Penguins are generally smaller than the predicted minimum body size for marine endotherms. Anatomical observations of the little blue penguin (Eudyptula minor) suggest that extant penguins actively defeat the lower size threshold using regional heterothermy. The wing arteries in the little blue penguin form a humeral plexus, a series of three parallel arteries (including the marginal artery) that stem from the axillary artery, replacing a single brachial artery. Each artery of the plexus is associated with at least two veins to form a counter current heat-retention system. The humeral plexus thus restricts heat from entering distal areas of the wing and dissipating into seawater, ultimately reducing the bulk mass required for heat production and insulation. Humeral plexi are confirmed as a synapomorphic character of the Spheniscinae, with the humeral plexus of E. minor most similar to that of the African penguin Spheniscus demersus. The humeral plexus represents a loophole in body size minima of marine endotherms and offers insight into the ecology of living penguins.
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Southwell, Colin, Charles G. M. Paxton, and David L. Borchers. "Detectability of penguins in aerial surveys over the pack-ice off Antarctica." Wildlife Research 35, no. 4 (2008): 349. http://dx.doi.org/10.1071/wr07093.
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Knowledge of penguin abundance at regional and circumpolar scales across the Southern Ocean is important for the development of ecosystem models and to estimate prey consumption by penguins to assess potential competition with fisheries’ operations. One means of estimating penguin abundance is to undertake aerial surveys across the pack-ice surrounding Antarctica where penguins forage. However, it has long been recognised that aerial counts and resultant abundance estimates are likely to be negatively biased unless detectability is estimated and taken into account. Mark–recapture line-transect methods were used to estimate the detectability of penguin groups resting on ice floes during helicopter surveys over the pack-ice off Antarctica. Group size had the greatest effect of several measured covariates on detectability. Despite a concerted effort to meet the central assumption of conventional line-transect sampling (all objects on the transect line are detected), this was close to being achieved by single observers only in the case of the occasional very large group of >20 penguins. Emperor penguins were more detectable than Adélie penguins. Although observers undertook an extensive simulation training program before the survey, overall they improved in their ability to detect penguin groups throughout the survey. Mark–recapture line-transect methods can provide less biased estimation than conventional line-transect methods in aerial survey applications. This improvement comes with some costs, including the need for more demanding data-recording procedures and the need to use larger, more expensive aircraft. These additional costs will often be small compared with the basic cost, but the gain in terms of improved estimation may be substantial.
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Ando, Tatsuro, and Keisaku Fukata. "A well-preserved partial scapula from Japan and the reconstruction of the triosseal canal of plotopterids." PeerJ 6 (August 25, 2018): e5391. http://dx.doi.org/10.7717/peerj.5391.
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The discovery of a well-preserved cranial end of a plotopterid scapula from the Early Oligocene Jinnobaru Formation in southwestern Japan has provided a fine example of its bone structure and has enabled the reconstruction of the triosseal canal (canalis triosseus) of the unique extinct penguin-like bird. It is believed that plotopterids performed penguin-like underwater propulsion using wings that were similar to those of penguins. Until this discovery, the lack of well-preserved plotopterid scapulae hindered reconstruction of the canalis triosseus, which is an important structure for the wing-upstroke. We reconstructed a composite model of the canalis triosseus based on the new scapula. The reconstructed size of the canal is as large as that in Emperor Penguins (Aptenodytes forsteri), suggesting that the bird had a large and powerful m. supracoracoideus, which is the essential muscle for the powered upstroke required for wing-propelled diving. Plotopterids likely have had the same functional requirement as penguins, the powerful wing-upstroke in the water. They must have also been capable swimmers. This scapula accounts for the structural difference between plotopterids and penguins in terms of the canalis triosseus. The large canalis triosseus of plotopterids was composed of the elongated acromion of the scapula, while penguins have a long processus acromialis claviculae for the same function.
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Xie, Shangzhe, and Todd J. McWhorter. "Fecal Glucocorticoid Metabolite Concentration as a Tool for Assessing Impacts of Interventions in Humboldt Penguins (Spheniscus humboldti)." Birds 2, no. 1 (March 1, 2021): 106–13. http://dx.doi.org/10.3390/birds2010007.
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It is currently unknown if current guidelines for collecting and interpreting blood corticosterone in flying birds can be extrapolated to penguins. It is also difficult to collect blood quickly without causing stress to a penguin. Therefore, immunoreactive fecal glucocorticoid metabolites (FGCMs) may be the most practical and minimally invasive way of monitoring the stress levels of penguins. This study investigated the reliability of FGCMs for monitoring stress levels in captive Humboldt Penguins (Spheniscus humboldti) at Jurong Bird Park, Singapore. Humboldt Penguin feces were randomly sampled and pooled from the exhibit for 2 months. The penguins were restrained and transported on three separate occasions to simulate stressful events. The feces were analyzed using an enzyme immunoassay to measure corticosterone levels. There were significant increases lasting 3 to 7 days in the FGCM levels after a stressful event. This method was then used to test whether accelerometer vests used for behavior quantification caused stress responses in these birds. There was no significant difference in FGCMs between time periods with and without the accelerometer vests. The results indicated that FGCMs can be an accurate indication of capture-, restraint-, and transport-related stress in Humboldt Penguins, and that accelerometer vests do not appear to cause stress.
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Barbosa, Andrés, Eva de Mas, Jesús Benzal, Julia Ines Diaz, Miguel Motas, Silvia Jerez, Luis Pertierra, et al. "Pollution and physiological variability in gentoo penguins at two rookeries with different levels of human visitation." Antarctic Science 25, no. 2 (March 20, 2013): 329–38. http://dx.doi.org/10.1017/s0954102012000739.
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AbstractHuman activity and specifically tourism has been increasing in Antarctica over the last few years. Few studies have examined the indirect effects of human visits on Antarctic penguin rookeries. This work aims to study the differences between a highly visited (Hannah Point) and a rarely visited (Devil's Point, Byers Peninsula) gentoo penguin rookery on Livingston Island. Our results suggest that potential indirect effects of human impact are observed in gentoo penguins at Hannah Point, a colony heavily visited by tourists. Penguins at Hannah Point showed a higher presence of heavy metals such as Pb and Ni and a higher number of erythrocytic nuclear abnormalities than penguins at Devil's Point. Immunological parameters showed different results depending on whether we consider the cellular response - the number of lymphocytes being higher in penguins from Hannah Point - or the humoral response - the level of immunoglobulins being higher in penguins from Devil's Point. Measurements of corticosterone levels in feathers and heterophil/lymphocyte (H/L) ratio in blood showed lower levels in the heavily visited rookery than in the rarely visited rookery. Finally, we did not detect Campylobacter jejuni, a bacteria potentially transmitted by humans in either of the populations and we did not find any difference in the prevalence of Campylobacter lari between the populations.
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Bost, C. A., J. B. Thiebot, D. Pinaud, Y. Cherel, and P. N. Trathan. "Where do penguins go during the inter-breeding period? Using geolocation to track the winter dispersion of the macaroni penguin." Biology Letters 5, no. 4 (May 15, 2009): 473–76. http://dx.doi.org/10.1098/rsbl.2009.0265.
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Although penguins are key marine predators from the Southern Ocean, their migratory behaviour during the inter-nesting period remains widely unknown. Here, we report for the first time, to our knowledge, the winter foraging movements and feeding habits of a penguin species by using geolocation sensors fitted on penguins with a new attachment method. We focused on the macaroni penguin Eudyptes chrysolophus at Kerguelen, the single largest consumer of marine prey among all seabirds. Overall, macaroni penguins performed very long winter trips, remaining at sea during approximately six months within the limits of the Southern Ocean. They departed from Kerguelen in an eastward direction and distributed widely, over more than 3.10 6 km 2 . The penguins spent most of their time in a previously unrecognized foraging area, i.e. a narrow latitudinal band (47–49° S) within the central Indian Ocean (70–110° E), corresponding oceanographically to the Polar Frontal Zone. There, their blood isotopic niche indicated that macaroni penguins preyed mainly upon crustaceans, but not on Antarctic krill Euphausia superba , which does not occur at these northern latitudes. Such winter information is a crucial step for a better integrative approach for the conservation of this species whose world population is known to be declining.
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Saiyed, Sana T., Lydia M. Hopper, and Katherine A. Cronin. "Evaluating the Behavior and Temperament of African Penguins in a Non-Contact Animal Encounter Program." Animals 9, no. 6 (June 6, 2019): 326. http://dx.doi.org/10.3390/ani9060326.
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Animal ambassador programs are increasingly prevalent in zoos, yet few studies have investigated their impact on animal welfare. We assessed the effects of an ambassador program on the behavior of a colony (N = 15) of zoo-housed African penguins (Spheniscus demersus) and evaluated whether individual characteristics were predictive of participation. Behavioral data were collected for 16 weeks and included 43 “penguin encounters”, during which zoo visitors entered a designated portion of the penguins’ enclosure. When comparing colony behavior following encounters to behavior during a matched control period lacking an encounter, we found no significant difference between affiliative or aggressive behaviors, suggesting that the encounters did not disrupt interactions in the colony. The same was true when comparing behavior preceding the encounter to a matched control period, indicating that any anticipatory period was similarly non-disruptive. Space use during encounters suggested comfort near visitors. We also measured penguin temperament on the shy-bold continuum by recording the birds’ response to novel objects and found that penguins’ temperament, sex, and age were predictive of participation. We concluded that this program had a neutral or positive impact on penguin welfare and considered the findings in relation to aspects of the ambassador program that provided penguins with control over their involvement.
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Arce, Rodrigo, Irene Ferreiro, Joaquín Hurtado, Fabián Aldunate, Paula Perbolianachis, Diego Simón, Gonzalo Moratorio, Pilar Moreno, and Juan Cristina. "Noninvasive Surveillance and Evolutionary Insight into Siadenovirus among Antarctic Penguins." Transboundary and Emerging Diseases 2023 (December 21, 2023): 1–9. http://dx.doi.org/10.1155/2023/9743267.
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Avian siadenoviruses infect diverse terrestrial and aquatic birds worldwide. Antarctica hosts several avian species that are susceptible to siadenovirus infection, such as penguins and South Polar skuas. However, the presence, diversity, and transmission of these viruses in Antarctic birds are poorly understood due to limited surveillance and sequence data. In this study, we performed a noninvasive surveillance of avian siadenoviruses using fecal samples collected from waterbirds at King George Island (part of South Shetland Islands, Antarctica) from late January to mid-February 2023. Polymerase chain reaction, sequencing, and phylogenetic analysis were used to investigate the occurrence, genetic diversity, and evolutionary relationships of these viruses in this unique environment. The results of these studies confirmed the presence of siadenoviruses in penguins living along the southeastern coast of King George Island. Distinct viral strains, specific to each penguin species studied, were found suggesting limited interspecies transmission and a complex viral ecosystem within Antarctic bird populations. Siadenovirus strains isolated from penguin’s species were genetically distinct from those infecting South Polar skuas. An in silico 3D modeling of hexon proteins from siadenoviruses gathered from gentoo penguins permitted to detect key amino acid substitutions in the FG2 domain that may affect capsid structure and function. The persistent prevalence of siadenoviruses in Antarctica underscores the need for ongoing surveillance to understand the evolutionary dynamics of viruses in this region. This study is the first to noninvasively detect siadenoviruses in Antarctic penguins, opening a new avenue for viral research. This approach not only sheds light on viral dynamics but also contributes to the conservation of Antarctica’s unique wildlife and biodiversity, especially in the face of increasing global warming.
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Davis, Lloyd S., Martin Renner, David Houston, Lei Zhu, Wiebke Finkler, and Thomas Mattern. "The breeding biology of erect-crested penguins, Eudyptes sclateri: Hormones, behavior, obligate brood reduction and conservation." PLOS ONE 17, no. 10 (October 12, 2022): e0275106. http://dx.doi.org/10.1371/journal.pone.0275106.
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Erect-crested penguins are the least studied of all penguins. They breed on two isolated subantarctic island groups, the Antipodes and Bounty Islands. Sporadic nest counts indicate a dramatic decline in numbers of erect-crested penguins over the last 50 years. Here we present data from a study undertaken in 1998 on the breeding biology, behavior and hormones of erect-crested penguins. It represents, even today, by far the most detailed data available on this species. The penguins exhibited extreme reversed egg-size dimorphism, whereby the first-laid A-egg was much smaller than the second-laid B-egg. A-eggs were lost before (42.3%) or on (37.8%) the day the B-egg was laid, and none survived more than 7 days after that. The penguins were in a low state of reproductive readiness, as evidenced by low levels of copulation, fighting, and testosterone in males during the courtship/laying period when, curiously, plasma levels of testosterone were at least as high in females. The laying interval (5.4 days) is the longest recorded for any penguin species, and incubation was highly variable until clutch completion. Most nests (91.2%) contained no nesting material and eggs were laid directly onto the ground. A-eggs were lost mainly by rolling out of the nest. However, even when prevented from doing so by an experimental manipulation, A-eggs survived no longer than those in control nests. Testosterone levels in males increased after clutch completion, when they remained in attendance at the nest for up to 13 days, despite females assuming most of the incubation duties. The bills of males were significantly larger than those of females and probably help with guarding the nest. We discuss explanations for obligate brood reduction in crested penguins and the options for conservation in light of our census results, which indicate that this enigmatic penguin species could be in trouble.
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Niemandt, Corne, Kit M. Kovacs, Christian Lydersen, Bruce M. Dyer, Kjell Isaksen, G. J. Greg Hofmeyr, Fridtjof Mehlum, and P. J. Nico de Bruyn. "Chinstrap and macaroni penguin diet and demography at Nyrøysa, Bouvetøya." Antarctic Science 28, no. 2 (November 30, 2015): 91–100. http://dx.doi.org/10.1017/s0954102015000504.
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AbstractKnowledge regarding interactions between predators and their prey is fundamental for understanding underlying links between climate change and ecosystem responses, including predator demographics, in the Southern Ocean. This study reports data on reproductive performance, total population size and diet composition for macaroni and chinstrap penguins breeding at Nyrøysa on Bouvetøya during the summers of 1996–97, 1998–99, 2000–01 and 2007–08. The breeding populations of these two species at Nyrøysa decreased significantly over the study period, with an 80% decline for chinstraps and a 50% decline for macaroni penguins, despite relatively high levels of chick production. During this period macaroni penguins at this site ate a diverse diet, dominated by myctophid fish and two krill species, whereas chinstrap penguins were Antarctic krill specialists. The population changes are probably primarily due to the expanding Antarctic fur seal population, and also to landslides that are the result of increased melting on the island which have destroyed penguin breeding sites. Additional impacts from global warming of the ocean might also be playing a role and could exacerbate the decline in these penguin populations if krill and other prey are negatively impacted in the future in this region. The local chinstrap penguin population would probably be most heavily affected given its narrow feeding niche and small current population size.
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Chiew, Samantha J., Kym L. Butler, Sally L. Sherwen, Grahame J. Coleman, Vicky Melfi, Alicia Burns, and Paul H. Hemsworth. "Effect of Covering a Visitor Viewing Area Window on the Behaviour of Zoo-Housed Little Penguins (Eudyptula minor)." Animals 10, no. 7 (July 18, 2020): 1224. http://dx.doi.org/10.3390/ani10071224.
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Studies on the effects of visitors on zoo animals have shown mixed findings and as a result, the manner in which visitors affect zoo animals remains unclear for many species, including a rarely studied taxa such as penguins. Penguins are a common zoo-housed species and have been shown to display huddling, vigilance and avoidance towards zoo visitors which can be indicative of fear. Here, we examined the effects of covering one visitor viewing area window, out of four, on little penguin (Eudyptula minor) behaviours that may be indicative of fear. Two treatments were randomly imposed on different days: (1) The main visitor viewing area window, where most visitor-penguin interactions occurred, was uncovered (‘Main window uncovered’) and (2) The main visitor viewing area window was covered (‘Main window covered’). Penguin numbers and behaviour were recorded near the main visitor viewing area window and the three other visitor viewing area windows, as well as one area not visible to visitors (‘Corner’ area). Furthermore, visitor numbers and visitor behaviour were recorded at all four visitor viewing area windows. Covering the main visitor viewing area window reduced the proportion of visitors present at this window by about 85% (p < 0.001) and reduced potentially threatening visitor behaviours at this window such as tactile contact with the window, loud vocalisations and sudden movement (p < 0.05). When the main visitor viewing area window was covered, the proportion of penguins present increased by about 25% (p < 0.05), the proportion of visible penguins preening in the water increased by about 180% (p < 0.05) and the proportion of visible penguins vigilant decreased by about 70% (p < 0.05) in the area near this main window. A preference for the Corner area was also found whereby 59% and 49% of penguins were present in this area when the main window was uncovered and covered, respectively. These results provide limited evidence that the little penguins in this exhibit showed an aversion to the area near the main visitor viewing area window when it was uncovered based on the increased avoidance and vigilance and decreased preening in the water in this area. This suggests visitors may be fear-provoking for these little penguins. However, it is unclear whether visual contact with visitors per se or other aspects of visitor contact, such as visitor-induced sounds and vibrations, were responsible for this apparent aversion when this window was uncovered.
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Johnson, V. Renea. "Long-Term Follow-up of Osteoarthritis in Three Humboldt Penguins Treated with Acupuncture." American Journal of Traditional Chinese Veterinary Medicine 17, no. 2 (August 1, 2022): 47–53. http://dx.doi.org/10.59565/dluk3058.
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Humboldt penguins, (Spheniscus humbolti) are medium-sized penguins from the rocky shores of Chile and Peru. Their lifespan in the wild is 20-25 years and in captivity 20-30 years. Three geriatric penguins at the Santa Barbara Zoological Park displayed various degrees of lameness and decreased swim time in their pool. Radiographs revealed osteoarthritis in numerous joints. Conventional treatments with various non-steroidal anti-inflammatory drugs (NSAIDs) were minimally effective at improving their mobility. The penguins were part of a zoo rookery and were not used to being handled. The traditional Chinese veterinary medicine (TCVM) examinations were kept brief and treatments done under the supervision of the zoo veterinary staff. The three penguins received a TCVM Pattern diagnosis of Kidney Qi Deficiency with local Stagnation in various joints. Dry needle acupuncture treatments utilizing minimal restraint were administered monthly for a year. Between acupuncture treatments, conventional medication was also administered. During the year of treatment, the geriatric penguins’ quality of life showed some improvement. One of the penguin’s mobility improved enough to again swim in the pool and catch fish during the feeding sessions. The other two penguins demonstrated some mild improvement with their mobility on land and swam more frequently in the pool. These improvements allowed them to remain part of their colony.
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Golubev, Sergey. "Diet and Feeding Behavior of the South Polar Skuas Stercorarius maccormicki in the Haswell Islands, East Antarctica." Birds 5, no. 2 (May 31, 2024): 240–54. http://dx.doi.org/10.3390/birds5020016.
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The diet and feeding behavior of South Polar Skuas (Stercorarius maccormicki) are well studied within the species’ breeding range but are poorly understood on the Haswell Islands. The aim of this study was to determine how South Polar Skuas use available resources during the pre-breeding and breeding periods at the Haswell Archipelago (66°31′ S, 93°01′ E, Davis Sea, Southern Ocean) under conditions of prolonged human activity. I studied pellets, spontaneous regurgitation, and stomach contents of feathered birds to study the diet of skuas and used direct observations of their feeding behavior. South Polar Skuas at the Haswell Islands fed primarily on the Emperor Penguin (Aptenodytes forsteri) colony and on terrestrial resources in the Adélie Penguin (Pygoscelis adeliae) and fulmarine petrel colonies. The dominant prey of skuas were breeding Antarctic penguins. Emperor Penguins and Adélie Penguins make up the bulk of the skuas’ diet in the pre-breeding and breeding periods. Surface feeding at sea was observed in the post-breeding period. In recent decades, kitchen waste supported the skua population. Scavenging (placenta and feces of Weddell seals [Leptonychotes weddellii], frozen eggs, chicks and adults of breeding bird species, kitchen refuse) is the dominant strategy for obtaining food. Adélie Penguin eggs and chicks were the main food items of the South Polar Skuas in the Haswell Archipelago. Skua predation could potentially influence the breeding success of Adélie Penguins and fulmarine petrels, but the extent of the impact is unknown. The impact of the South Polar Skua on Emperor Penguins is negligible because skuas feed mainly on frozen chicks and eggs of the species.
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ARGILLA, L. S., L. HOWE, B. D. GARTRELL, and M. R. ALLEY. "High prevalence ofLeucocytozoonspp. in the endangered yellow-eyed penguin (Megadyptes antipodes) in the sub-Antarctic regions of New Zealand." Parasitology 140, no. 5 (January 29, 2013): 672–82. http://dx.doi.org/10.1017/s0031182012002089.
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SUMMARYYellow-eyed penguins (YEPs) have suffered major population declines over the past 30 years, with no single cause established.Leucocytozoonwas first identified in yellow-eyed penguins in 2005. During the 2008/09 breeding season, a high mortality was seen in both mainland yellow-eyed penguins as well as those on Enderby Island of the Auckland Islands archipelago. A high overall prevalence ofLeucocytozoonspp. in association with a high incidence of chick mortality was observed during this period on Enderby Island. One chick had histological evidence of leucocytozoonosis with megaloschizonts in multiple organs throughout its body. In addition, a high prevalence (73·7%) ofLeucocytozoonwas observed by PCR in the blood of adult Enderby yellow-eyed penguins taken during the 2006/07 season. These findings were different from the low prevalence detected by PCR on the coast of the South Island (11%) during the 2008/2009 breeding session and earlier on Campbell Island (21%) during the 2006/2007 breeding session. TheLeucocytozoonspp. sequences detected lead us to conclude that theLeucocytozoonparasite is common in yellow-eyed penguins and has a higher prevalence in penguins from Enderby Island than those from Campbell Island and the mainland of New Zealand. The Enderby Island yellow-eyed penguins are infected with aLeucocytozoonspp. that is genetically distinct from that found in other yellow-eyed penguin populations. The role ofLeucocytozoonin the high levels of chick mortality in the yellow-eyed penguins remains unclear.
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Panasiuk, Anna, Justyna Wawrzynek-Borejko, Aleksandra Musiał, and Małgorzata Korczak-Abshire. "Pygoscelis penguin diets on King George Island, South Shetland Islands, with a special focus on the krill Euphausia superba." Antarctic Science 32, no. 1 (January 14, 2020): 21–28. http://dx.doi.org/10.1017/s0954102019000543.
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AbstractIn 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.
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Brown, Christopher R. "Energy requirements and food consumption of Eudyptes penguins at the Prince Edward Islands." Antarctic Science 1, no. 1 (March 1989): 15–21. http://dx.doi.org/10.1017/s0954102089000040.
Full textAbstract:
Macaroni penguins (Eudyptes chrysolophus) and rockhopper penguins (E. chrysocome) account for a substantial proportion of the avian biomass at the subantarctic Prince Edward Islands (47°S, 38°E) in summer, when both species are breeding at the islands. Information on breeding population sizes, breeding and moulting activities, and diets were combined with measurements of the penguins' energy expenditures to construct a bioenergetic model of their energy requirements and food consumption at the islands. Total energy requirements of adults and chicks amounted to 460 × 109 kJ and 162 × 109 kJ for macaroni and rockhopper penguins, respectively. Food consumption was estimated to amount to a total of 166 000 tonnes during the seven-month breeding and moulting cycle, of which macaroni penguins consumed 75%. Most, if not all, of this food is taken within a 200-km radius of the islands. Available information suggests that potential primary production in the immediate vicinity of the islands is sufficient to support the macaroni and rockhopper penguin populations. However, the importance in the diets of the penguins of several prey species more typical of Antarctic and subtropical regions suggests that the penguins rely to a large extent on the importation of prey populations from other areas.
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DIPIERRO, SERENA, LUCA LOMBARDINI, PIETRO MIRAGLIO, and ENRICO VALDINOCI. "THE PHILLIP ISLAND PENGUIN PARADE (A MATHEMATICAL TREATMENT)." ANZIAM Journal 60, no. 1 (July 2018): 27–54. http://dx.doi.org/10.1017/s1446181118000147.
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Penguins are flightless, so they are forced to walk while on land. In particular, they show rather specific behaviours in their homecoming, which are interesting to observe and to describe analytically. We observed that penguins have the tendency to waddle back and forth on the shore to create a sufficiently large group, and then walk home compactly together. The mathematical framework that we introduce describes this phenomenon, by taking into account “natural parameters”, such as the eyesight of the penguins and their cruising speed. The model that we propose favours the formation of conglomerates of penguins that gather together, but, on the other hand, it also allows the possibility of isolated and exposed individuals.The model that we propose is based on a set of ordinary differential equations. Due to the discontinuous behaviour of the speed of the penguins, the mathematical treatment (to get existence and uniqueness of the solution) is based on a “stop-and-go” procedure. We use this setting to provide rigorous examples in which at least some penguins manage to safely return home (there are also cases in which some penguins remain isolated). To facilitate the intuition of the model, we also present some simple numerical simulations that can be compared with the actual movement of the penguin parade.
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Menéndez-Blázquez, Javier. "Penguins of Argentina: a bibliometric analysis." El Hornero 35, no. 2 (December 1, 2020): 77–86. http://dx.doi.org/10.56178/eh.v35i2.439.
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This study analyzes the scientific literature published on penguins in Argentina between 1985 and 2019. It examines the characteristics and the temporal variation in the number of publications, the total number of authors, the percentage of participation of Argentine researchers, the species and region of study, as well as the research topics they address. The results show a tendency towards an increase in papers and studies of these birds, the total number of authors, and the participation of researchers belonging to Argentine research centers during the period analyzed. The most studied penguin species was the Magellanic Penguin (Spheniscus magellanicus), followed by the Southern Rockhopper Penguin (Eudyptes chrysocome) and the Gentoo Penguin (Pygoscelis papua). The most addressed research topics were foraging and diet, followed by reproduction and reproductive success, conservation and wildlife management, population dynamics and physiology and histology, which were carried out mainly in the Patagonian region and in the Malvinas Islands. The results help to understand the past, present and future state of scientific literature, which will strengthen decision-making on future research on penguins.
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Chiaradia, André, Manuela G. Forero, Keith A. Hobson, and J. Mike Cullen. "Changes in diet and trophic position of a top predator 10 years after a mass mortality of a key prey." ICES Journal of Marine Science 67, no. 8 (June 29, 2010): 1710–20. http://dx.doi.org/10.1093/icesjms/fsq067.
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Abstract Chiaradia, A., Forero, M. G., Hobson, K. A., and Cullen, J. M. 2010. Changes in diet and trophic position of a top predator 10 years after a mass mortality of a key prey. – ICES Journal of Marine Science, 67: 1710–1720. After the disappearance of primary prey, seabirds exhibit gradually decreased breeding performance, and eventually the population size drops. Results are presented of an investigation into the diet of little penguins (Eudyptula minor) at Phillip Island, Australia, during a period when their key prey, pilchard (Sardinops sagax), declined dramatically. Data from stomach flushing (1982–2006) were used, supported by stable isotope (δ15N, δ13C) analyses of blood samples (2003, 2004, and 2006). The effect of the pilchard mortality on penguin diet was immediate, the birds shifting to a diet almost devoid of pilchard, and this was followed by 2 years of low breeding success, with considerably fewer penguins coming ashore. During periods when pilchard was not part of the diet, penguins consumed prey of a higher trophic level, e.g. higher values of δ15N. Variability in penguin blood δ15N coincided with years of low prey diversity. The disappearance of pilchard resulted in a decrease in prey diversity and led penguins to “fish up” the foodweb, possibly because of the simplified trophic structure. After 1998, however, breeding success re-attained average levels and the numbers of penguins coming ashore increased, probably because of increased abundance of prey other than pilchard after a 3-year period of food scarcity. Although little penguins apparently compensated over time, a less-flexible diet could make them ultimately vulnerable to further changes in their foodweb.
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Mayr, Gerald, Vanesa L. De Pietri, Leigh Love, Al A. Mannering, Joseph J. Bevitt, and R. Paul Scofield. "First Complete Wing of a Stem Group Sphenisciform from the Paleocene of New Zealand Sheds Light on the Evolution of the Penguin Flipper." Diversity 12, no. 2 (January 26, 2020): 46. http://dx.doi.org/10.3390/d12020046.
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We describe a partial skeleton of a stem group penguin from the Waipara Greensand in New Zealand, which is tentatively assigned to Muriwaimanu tuatahi. The fossil includes the first complete wing of a Paleocene penguin and informs on previously unknown features of the mandible and tibiotarsus of small-sized Sphenisciformes from the Waipara Greensand. The wing is distinguished by important features from that of all geologically younger Sphenisciformes and documents an early stage in the evolution of wing-propelled diving in penguins. In particular, the wing of the new fossil exhibits a well-developed alular phalanx and the distal phalanges are not flattened. Because the wing phalanges resemble those of volant birds, we consider it likely that the wing feathers remained differentiated into functional categories and were not short and scale-like as they are in extant penguins. Even though the flippers of geologically younger penguins may favor survival in extremely cold climates, they are likely to have been shaped by hydrodynamic demands. Possible selective drivers include a diminished importance of the hindlimbs in subaquatic propulsion, new foraging strategies (the caudal end of the mandible of the new fossil distinctly differs from that of extant penguins), or increased predation by marine mammals.