Academic literature on the topic 'Penguins'
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Journal articles on the topic "Penguins"
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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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Kanagasabai, Lenin. "Diminution of real power loss by novel gentoo penguin algorithm." International Journal of Informatics and Communication Technology (IJ-ICT) 9, no. 3 (2020): 151–56. https://doi.org/10.11591/ijict.v9i3.pp151-156.
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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.
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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 (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 (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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Golubev, Sergey V. "Aberrant and deformed Antarctic penguins and unusual eggs." Notornis 67, no. 2 (2020): 459. https://doi.org/10.63172/287069hltcsx.
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Nineteen cases of physical deformities, colour aberrations, and unusual eggs were recorded in emperor penguins (Aptenodytes forsteri) and Adélie penguins (Pygoscelis adeliae) from the Haswell archipelago in the Davis Sea, East Antarctica, during 1956–2016. Two very small eggs and one very large egg were recorded from emperor penguins, and two very small eggs from Adélie penguins. Physical deformities included beak deformities in two emperor penguin adults and two chicks, and two chicks had deformed spines. Colour aberrations included the ino mutation in a juvenile emperor penguin, and examples of dilution (two cases), progressive greying (two cases), and isabellinism in adult Adélie penguins. Feather-loss disorders were recorded in two downy emperor penguin chicks. Data on the occurrence of identified abnormalities and disorders are given. These cases provide a baseline for assessing changes in the frequency of physical abnormalities in these Antarctic penguin species.
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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 (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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Barquete, Viviane, Leandro Bugoni, Rodolfo P. Silva-Filho, and Andréa C. Adornes. "Review of records and notes on King Penguin (<i>Aptenodytes patagonicus</i>) and Rockhopper Penguin (<i>Eudyptes chrysocome</i>) in Brazil." El Hornero 21, no. 1 (2006): 45–48. https://doi.org/10.56178/eh.v21i1.798.
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A review of previous findings and new records of King Penguin (Aptenodytes patagonicus) and Rockhopper Penguin (Eudyptes chrysocome) on the Brazilian coast is presented. In total there are six records of the King Penguin and ten records of the Rockhopper Penguin. Juvenile and adults of both species were found stranded mostly on Rio Grande do Sul coast, southern Brazil. Records of King Penguins are restricted to the summer season, while records of Rockhopper Penguins are mostly during winter. Rockhopper Penguin appears to displace more regularly to the Subtropical Convergence area, while King Penguins appear to be vagrant in Brazil, following the Malvinas Current.
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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 (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 (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 (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.
Dissertations / Theses on the topic "Penguins"
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Liljesthröm, Marcela. "Avian predation at a Southern Rockhopper Penguin Colony on Staten Island, Argentina /." Electronic version (PDF), 2005. http://dl.uncw.edu/etd/2005/liljesthromm/marcelaliljesthrom.pdf.
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Smith, Diane Lauren. "Penguin parenting : assortative mating, nest attendance and sex-specific chick provisioning in the African Penguin (Spheniscus demersus)." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/d1019993.
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Animal behaviour is especially sensitive to environmental variability and prey availability during the breeding season, and this is particularly true for non-volant, central place foragers such as the endangered African Penguin (Spheniscus demersus). Individual sex and morphology, as well as the level of assortment within mated pairs can influence both the behaviour and the reproductive success of species exhibiting biparental care. This study made use of a large biometric database and nest attendance video footage to determine the influence of intrinsic (assortative mating, brood size and chick age) and extrinsic (environmental conditions, anthropic disturbance) factors on breeding behaviour and performance of African Penguins on Bird Island, Algoa Bay, during peak breeding (March - July) in 2013. While sexual dimorphism in African Penguins is subtle, the colony-specific discriminant functions presented here provide an accurate sexing tool when only bill and flipper length are available. Despite the premise that selection of a large, high-quality mate in this longlived, monogamous seabird governs lifetime fitness, only low levels of assortative mating were found, and this only for earlier breeders, when larger females (but not males) bred. The 2013 season was a particularly successful one, coinciding with above-average sardine and anchovy abundance, and almost 80 percent of monitored nests were double-brooded, with very low levels of mortality. A- and B-chicks of double broods and singleton chicks grew at similar rates and exhibited similar body condition indices. In these conditions, chick developmental rates were independent of parental size, assortment or provisioning behaviour. Females raising a double brood were significantly lighter and in poorer body condition than those raising a single chick, although the same trend was not evident in males. Offspring sex ratio in 2013 (2.27:1) favoured male chicks, suggesting that there is potential to over-produce the larger sex when resources are plentiful. Peak nest arrival and departure times of parents did not change over the course of monitored breeding attempts (March-June), nor were they different for disturbed and undisturbed nests or for a single or double brood. The increase in CCTV-observed provisioning rate as chicks grew larger was best explained by brood size, at-sea chlorophyll a concentration, and maximum air temperature, but was unrelated to parental morphology or assortative index. Importantly, parental absenteeism commenced earlier and was markedly greater in nests frequently handled by researchers than in undisturbed nests. Both the time spent together by parents, and absenteeism were measurably affected by maximum afternoon air temperatures, the effects of which are expected to be exacerbated by poorer foraging conditions and climate change. A third of manually-monitored nests shared chick-guarding duties unequally, although this phenomenon was independent of parental sex or morphology. The adaptive benefits of mating patterns and division of labour during chick-rearing may only become apparent in a year of below-average food availability and it is highly recommended that this study be repeated in a year of scarce food resources. These findings augment past foraging ecology studies and demonstrate that investigator disturbance and environmental conditions can affect the nesting behaviour of this highly threatened seabird.
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Mattern, Thomas, and n/a. "Marine ecology of offshore and inshore foraging penguins : the Snares penguin Eudyptes robustus and Yellow-eyed penguin Megadyptes antipodes." University of Otago. Department of Zoology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070502.150734.
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Seabirds have become adapted for foraging in an oceanic environment that can be highly dynamic. Oceanographic processes determine the spatial distribution of seabird prey, while seasonality often has a temporal influence on prey availability. In penguins, these factors are reflected in the different species� foraging strategies. Penguins can broadly be categorized as inshore foragers that live in subtropical to temperate regions and profit from a stable food supply throughout the year close to their breeding sites, and offshore foragers that breed in a pelagic environment at higher latitudes where oceanographic processes and seasonality create much more dynamic, temporally limited prey situations. In this light, offshore foragers can be expected to be much more flexible in their foraging behaviour so as to quickly respond to changes in a dynamic marine environment, while inshore foragers are more likely to exhibit predictable foraging patterns. I examined the foraging ecology of two New Zealand penguin species - the offshore foraging Snares penguin Eudyptes robustus and the inshore foraging Yellow-eyed penguin Megadyptes antipodes and how their foraging strategies reflect an adaptation to the marine environment they exploit.
Diet composition of breeding Snares penguins (incubation and early chick-guard) was determined using the water-offloading method. Before the chicks hatched, the penguins generally brought little food back from their long foraging trips. During chick-guard, the stomach contents comprised mainly of crustaceans (~55%), fish (~24%) and cephalopods (~21%). However, the presence at times of many fish otoliths and squid beaks suggests that the latter two prey classes may play an even more important role in the adults� diet than the simple percentages based on mass suggest. The penguins� nesting routines were strongly synchronised between the years and correlated with the onset of the spring planktonic bloom. Using GPS data loggers and dive recorders I found that during the incubation phase, male penguins that performed long (ca. 2 week) foraging trips exhibited a strong affinity to forage in the Subtropical Front some 200 km east of the Snares. At that stage (late mid-October) the front featured elevated chlorophyll a concentrations, a pattern that can be observed every year. Thus, it seems that the front represents a reliable and predictable source of food for the male penguins. After the males returned, the female penguins also performed long foraging trips (<1 week) but never reached the front, primarily because they had to time their return to the hatching of their chicks. After the chicks had hatched, the female Snares penguins were the sole providers of food. At this stage, the penguins performed short foraging trips (1-3 days) and foraged halfway between the Snares and Stewart Island (ca. 70-90 km north of the Snares), where nutrient-rich coastal waters flow eastwards to form the Southland Current. The penguins concentrated their diving effort in these waters, underlining the importance of the warm coastal waters as a food source for breeding Snares penguins. However, diving behaviour between 2003 and 2004 differed with penguins searching for prey at greater depths in the latter year. This underlines the Snares penguins� behavioural flexibility in response to a changing marine environment.
The Yellow-eyed penguins as typical inshore foragers showed very consistent foraging patterns at all stages. GPS logger deployments on penguins at Oamaru revealed that the birds foraged almost exclusively at the seafloor and targeted specific areas that featured reefs or epibenthic communities. As a result, the penguins� at-sea movements appeared conservative and at times almost stereotypic. Nevertheless, a comparison of Yellow-eyed penguins breeding on the adjacent Codfish and Stewart islands revealed a degree of plasticity in the species� foraging behaviour. Birds from Codfish Island extended their foraging ranges considerably and switched from primarily bottom to mid-water foraging during the post-guard stage of breeding. It seems likely that this switch is a result of enhanced feeding conditions (e.g. increased prey abundance/quality) in an area further away from the island, but the time required to get there renders this strategy not viable when chicks are small and need to be guarded and fed on a daily basis. As such, the change of behaviour represents a traditional pattern rather than a dynamic response to a sudden change in the marine environment. In comparison, penguins from Stewart Island showed consistent foraging patterns during all stages of breeding. Given the high levels of chick starvation on Stewart Island, the lack of plasticity in foraging behaviour is surprising and might indicate that Yellow-eyed penguins find it difficult to react quickly to a sub-optimal food situation.
Overall, it seems that Yellow-eyed penguins show a specialisation for a consistent benthic environment and, thus, lack the behavioural flexibility apparent in Snares penguins, which find their food in a changing pelagic marine environment.
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Wilson, Rory Paul. "Breeding Jackass Penguins as pelagic predators." Doctoral thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/17653.
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Bibliography: pages 187-191.<br>The foraging of breeding Jackass Penguins Spheniscus demersus was studied in and around southwestern Cape Province, Saldanha Bay (33⁰ S, 18⁰ E), South Africa. Penguins are difficult to observe at sea. Hence, I devised a number of new techniques for studying the foraging behaviour of Jackass Penguins at sea. I built electronic and autoradiographic remote-sensing devices to measure swimming speed, distance travelled and time spent at each depth by foraging Jackass Penguins. Penguin swimming speed was reduced in proportion to the cross-sectional area of the devices, and results derived from birds wearing the devices had to be interpreted accordingly. Penguins do not regurgitate their stomach contents when handled, so I constructed a wet-offloading stomach pump which extracted 100% of the stomach contents. Using this pump, I determined that the rate of digestion of fish and squid by Jackass Penguins differed. Care is needed in diet interpretations where both fish and squid are major food items.
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Yoda, Ken. "Behavioural decisions of provisioning Adélie penguins." 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/149126.
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Moon, Katherine Louise. "Do terrestrial ectoparasites disperse with penguins?" Phd thesis, Canberra, ACT : The Australian National University, 2017. http://hdl.handle.net/1885/144227.
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Dispersal plays a critical role in evolution. Rare long-distance movements can lead to allopatric speciation, whereas frequent movements can facilitate gene flow among disjunct populations and prevent divergence. Dispersal between populations of a species may be difficult to observe directly, and is often inferred from indirect measures such as species occurrence data. Increasingly, however, high resolution genomic data are being used to clarify dispersal and gene flow, in many cases contradicting past assumptions. Islands are excellent model regions for investigating dispersal as they offer replicated habitats with clear geographic boundaries. The sub-Antarctic comprises some of the most geographically isolated island ecosystems in the world, representing an ideal model system for assessing the evolutionary consequences of long-distance dispersal. Strong winds, circumpolar oceanic currents, and extreme climatic cycles are thought to have effectively isolated many sub-Antarctic ecosystems, but a growing body of molecular evidence is beginning to question this rhetoric, with numerous species showing connectivity across the region. Connectivity patterns are, however, complex and are not always predictable from an organism’s inferred dispersal capacity. With environmental change placing unprecedented pressure on isolated ecosystems, there is a pressing need for improved understanding of dispersal processes and population connectivity via genomic analyses of diverse taxa. A number of sub-Antarctic species exhibit gene flow across the region despite lacking active long-distance dispersal capabilities. Brooding, sedentary crustaceans have, for example, rafted on buoyant kelp across thousands of kilometres of open ocean in the sub-Antarctic. The close symbiotic or parasitic relationships that such species maintain with the kelp has resulted in whole communities dispersing together. Indeed, active dispersal is often limited in parasites, which can depend almost entirely on mobile hosts for long-distance movement. A parasite that is unable to travel far with its host would, therefore, be expected to show considerable phylogeographic structure. For example, penguins primarily travel underwater but are hosts to terrestrial ectoparasites (most commonly ticks - Ixodes spp.) when they come ashore to breed. Aquatic host movements may represent a challenge to the survival of penguin ticks, restricting gene flow across their range. This thesis first reviews connectivity patterns and challenges throughout the sub-Antarctic, and then uses a multidisciplinary approach (genomic and physiological data) to test whether some terrestrial parasites (ticks: Acari) are able to travel long distances at sea with their aquatically dispersing hosts (penguins). Results indicate that penguin ticks are physiologically resilient, and may be capable of surviving the conditions faced during aquatic penguin movements between colonies. However, these movements appear to be too sporadic to maintain gene flow across the ticks’ ranges, resulting in broad-scale geographic structure. In contrast, movement on fine scales (within colonies) is inferred – based on lack of genomic structure – to be common, possibly facilitated by social interactions of hosts. These results emphasise the important role of dispersal in isolated regions for range expansion and diversification, and highlight the adaptability of parasites to their hosts’ environments.
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Booth, Jenny Marie. "Trophic ecology of breeding northern rockhopper penguins, Eudyptes Moseleyi, at Tristan da Cunha, South Atlantic Ocean." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005476.
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Northern Rockhopper penguin populations, Eudyptes moseleyi, are declining globally, and at Tristan da Cunha have undergone severe declines (> 90% in the last 130 years), the cause(s)of which are unknown. There is a paucity of data on this species in the South Atlantic Ocean, therefore their trophic ecology at Tristan da Cunha was studied, specifically focusing on diet, using stomach content analysis and stable isotope analysis (SIA), in conjunction with an analysis of diving behaviour, assessed using temperature-depth recorders. In order to evaluate the influence of gender on foraging, a morphometric investigation of sexual dimorphism was confirmed using molecular analysis. Additionally, plasma corticosterone levels were measured to examine breeding stage and presence of blood parasites as potential sources of stress during the breeding season. Northern Rockhopper penguins at Tristan da Cunha displayed a high degree of foraging plasticity, and fed opportunistically on a wide variety of prey, probably reflecting local small-scale changes in prey distribution. Zooplankton dominated (by mass) the diet of guard stage females, whereas small meso-pelagic fish (predominantly Photichthyidae)dominated diet of adults of both sexes in the crèche stage, with cephalopods contributing equally in both stages. Adults consistently fed chicks on lower-trophic level prey (assessed using SIA), probably zooplankton, than they consumed themselves indicating that the increasing demands of growing chicks were not met by adults through provisioning of higher- quality prey. SIA also indicated that adults foraged in different oceanic water masses when feeding for self-maintenance and for chick provisioning, thus temporally segregating the prey consumed for different purposes. It is possible that adults ‘selected’ these higher quality prey for themselves, or this may be a reflection of opportunistic behaviour. At Tristan da Cunha sexual dimorphism was observed in culmen dimensions (length, depth, width), with males having larger beaks and feeding on larger individuals of squid and fish than females. No sexual segregation in terms of foraging habitat (i.e. different water masses, based on ð¹³N or trophic level ð¹⁵N) during the breeding season or pre-moult period was revealed through SIA, and stomach content analysis revealed no sexual differences in prey species targeted. The results of SIA of feathers indicate that during the pre-moult period birds foraged in different water masses than during the breeding period. The fact that throughout the breeding season birds foraged in similar habitats suggests no intra-specific competition, despite both sexes feeding on the same prey.Birds were generally diurnal, daily foragers (12 – 16 hr trips), with extended trips (maximum duration 35.5 hours) and nocturnal diving recorded in a few individuals. Birds dived well within their physiological limits, predominantly utilising the upper 20m of the water column, employing two different strategies to target different prey items. Long, deep (30 – 40 m), energetically costly dives were performed when targeting energy-rich prey (fish), and a greater number of shorter, shallower (5 – 20 m), energy-efficient dives were performed when targeting prey with a lower energy content (zooplankton). More than half of the sampled study population were infected with the intra-cellular blood parasite Babesia, but infection showed no relationship to body mass, corticosterone levels or breeding success. Fasting birds showed no signs of elevated corticosterone levels, suggesting they had acquired sufficient fat reserves prior to breeding. Failed breeders did not exhibit elevated corticosterone levels. Tristan skuas, Catharacta antarctica hamiltoni, were observed to be a significant cause of egg and chick mortality. The absence of sex-based differences in foraging, and the absence of any signs of stress in relation to body mass, presence of Babesia or breeding stage, suggest that there are no obvious signs of high levels of stress or food limitations during breeding at Tristan da Cunha.
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Ralph, Mark Shaun. "Aspects of the breeding biology of the African penguin on Bird Island, Algoa Bay." Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/840.
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It is important to the survival of the Africa Penguin (Spheniscus demersus) population that breeding at the nest site is successful and that large numbers of chicks are fledged into the breeding population. Nest distribution on Bird Island is not random and locality preferences for breeding exist. Although it seems that sufficient area exists on Bird Island for penguin nests, it can hardly be considered as suitable to optimise breeding. During prolonged heat conditions, breeders relocated to nest sites that were sheltered. Nests that were below ground in burrows was the only habitat that did not suffer nest desertion whilst all the other habitat types (including those that were sheltered) experienced 2-3 fold declines in nest numbers. Nests density and the selection of suitable nest sites are significantly influenced by the stage of breeding that the majority of birds are in, yet nests that are shaded, well-ventilated and protected seem to be the most preferred sites for breeding. Adults that attempt to breed are considered then to be in a healthy condition and will usually lay a double clutch (Randell 1983). The frequency of double clutches being laid during the peak breeding attempt was significantly higher compared to the replacement one. Breeding failure was fairly similar to breeding success during the incubation stage for nests with double clutches however, was substantially higher in single clutches. The growth rate of chicks was best fit to the von Bertalanffy growth curve in 90 percent of the cases. The overall growth rate of chicks from double broods was faster than from single broods, however was not significant. A-chicks maitain a high growth rate until they fledged. Yet, the sibling B-chick recorded the lowest growth rate of the successfully fledged chicks and up to until day 30 recorded a similar weight to those chicks that failed to fledge. Contrary to findings of Randall (1983), chicks from single broods delayed fledging, recorded lowest overall growth rates and experienced the greatest weight loss of all groups, yet fledged successfully. In order for chicks to fledge successfully, they needed to obtain a weight of 1060 g before day 30.5 in their growth cycles to avoid death due to startvation later on. Single chicks that are raised from a double cluth, fledged more other than chicks raised from a single clutch. Unfit or ill-adapted breeders that are marginal in the capabilities of raising offspring, already manifest in a small clutch size and offspring unable to obtain adequate weights during the initial stages of growth.
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Black, Caitlin Emily. "Variation in the phenology of Pygoscelis penguins." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:00c306b4-f7c4-4f11-8749-1e3ae118746b.
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Variation in phenology is linked to the timing of environmental variables and influences survival at both the individual and colony level. Therefore, understanding a species' annual cycle is vital to its ecology and conservation. By reviewing literature on Pygoscelis penguin phenology in Chapter 1, I identify major gaps, both spatially and temporally, in our knowledge of the timing of events in the three species (Adeélie, Pygoscelis adeliae; chinstrap, and Pygoscelis antarctica; gentoo, Pygoscelis papua): particularly, 1) during the guard phase, 2) their behaviour in winter, 3) the phenology of colonies inhabiting locations away from scientific bases, and 4) the general phenology of chinstrap penguins. Chapter 2 assesses which time-lapse camera methods are most relevant to seabird research, highlighting the capabilities and limitations of cameras in past studies and how they may be best applied to future research. Chapter 3 examines the timing of the guard phase in gentoo penguins and how chick aggregation behaviours vary across several sites. Chapters 4 and 5 show variation in winter abundance at breeding sites in both gentoo and Adélie penguins related to abiotic factors and colony location. Lastly, Chapter 6 fills in gaps in the known timing and duration of phenology events in gentoo and chinstrap penguins across their full latitudinal ranges, while relating these timings to chick survival. In the conclusion, I summarize the main findings of the thesis, focusing on three major themes that were observed across the four data chapters and their implications: 1) behaviours are not consistent across colony locations 2) nor between years, and these behaviours depend on 3) local environmental conditions. I then synthesize these empirical findings from each of these chapters, discuss the implication of these findings to ecological theory and conservation policy, highlight some of the limitations of these studies, and recommend possibilities for future research.
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Ando, Tatsuro, and n/a. "New Zealand fossil penguins : origin, pattern, and process." University of Otago. Department of Geology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20080204.140701.
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Penguins are middle- to large-sized sea birds and are widely distributed in the Southern Hemisphere. They have completely lost the capability for the aerial flight, but are highly efficient wing-propelled swimmers and divers. They have a long fossil record over 60 million years, and their origin could possibly extend back to the late Cretaceous. This study aims to elaborate the course of penguin evolution and driving force of changes based on fossil records of penguins. Numerous fossil penguin specimens have been collected and studied from New Zealand, Antarctica, South America, Australia, and Africa. Studies on fossil penguins have spanned about 150 years history since Huxley (1859).
Previous works on fossil penguins have achieved excellent results, but at the same time, left considerable confusion on taxonomy and anatomical interpretation, mainly because of the poor nature of the penguin fossils in early studies. Examination of newly found materials and updated evaluation of previously studied materials are needed, using modern methods.
During about 150 years of fossil penguins study since Huxley1859, more than 40 genera and 70 species have been described. The number of specimens listed in the published literature amounts to more than 1300. Chapter II reviews all those fossil penguins in a summarised and consistent style, aiming to present the taxonomy used in this study as a primary and essential resource for research. The chapter also provides other information on fossil penguins, such as geological data and an assessment of the skeletal association of the specimens referred to a species.
Chapter III introduces the osteology of penguins, by describing and comparing the skeletal characteristics and variation of both extant and fossil species. Though previous works on penguins osteology are extensive, the interpretation of the homology, and resulted terminology, are occasionally inappropriate, or incorrect, because of the highly-specialised structure. Many of the new, yet undescribed, fossils prompt a comprehensive update of those previous studies, to understand the nature of morphological variation in penguins, and to correct or clarify confusion in previous works.
The New Zealand fossil penguin fauna is one of the most significant for fossil penguin studies, but there are many undescribed fossil penguin specimens. Chapter IV provides accounts of such materials. Chapter IV also reviews previously-described New Zealand fossil penguins, usually re-evaluated using new materials. This chapter includes reassessment of the controversial, first-described fossil penguin Palaeeudyptes antarcticus, description of an enigmatic new species (Pakudyptes hakataramea gen. et sp. nov.) which could elucidate the evolutionary pattern of the penguin wing, description of new materials of Platydyptes revealing a unique structure and functional interpretation, and redescriptions with functional interpretation of Pachydyptes and Archaeospheniscus.
Published relationships within penguins have not been adequately discussed but stated within rather rough frameworks, so that the relationships within penguins were unclear. Chapter V provides an explicit framework for the phylogeny of penguins. Osteology-based cladistic analysis was performed to seek out the relationships within penguins, using observations on both extant and fossil penguins. There are several important grades in penguin history, which are structurally distant from each other. Results also agree with the published views in which the extant penguins form a rigid group, but Simpson�s subfamily groupings are only partly supported. A postulated phylogenetic tree includes all known fossil penguin taxa including un-named ones.
Chapter VI, as a synthesis of contents of previous chapters, provides a broad interpretation of penguin evolution through the Cenozoic: origin, body size increase, demise of 'giant penguins', and the emergence of modern penguins. The chapter gives a global picture of the interaction of penguins, pinnipeds, cetaceans, and temperature and sea-level change. Two main sections are: 'Origin of penguins' and 'Evolutionary process of penguins.' The loss of aerial flight and increase of body size were possibly triggered by the K/T mass extinction event which drastically reduced the predatory pressure for early penguins. The 'giant penguins' survived until the Late Oligocene but declined as the oceans modernised, and new forms of whales with advanced feeding function appeared. There is controversy about appearance of modern penguins. The fossil-based hypothesis (relatively recent origin for crown-penguins) contradicts the molecular-based one (ancient origin for crown penguins), though 'hard evidence' at present does not easily refute either hypothesis.
Books on the topic "Penguins"
More sourcesBook chapters on the topic "Penguins"
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Bodley, Kate, and Todd L. Schmitt. "Penguins." In Zoo Animal and Wildlife Immobilization and Anesthesia. John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118792919.ch25.
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Fennelly, Lawrence J., and Marianna A. Perry. "Security Officers and Penguins (Yes, Penguins)." In Security Officers and Supervisors. CRC Press, 2024. http://dx.doi.org/10.4324/9781003402718-22.
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Cerchiara, Jack A. "Penguins." In Encyclopedia of Reproduction. Elsevier, 2018. http://dx.doi.org/10.1016/b978-0-12-809633-8.20610-9.
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"Penguins." In Last Child to Come Inside. McGill-Queen's University Press, 1998. http://dx.doi.org/10.1515/9780773581562-039.
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"Penguins." In Oceanic Birds of the World. Princeton University Press, 2019. http://dx.doi.org/10.1515/9780691197012-009.
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"Penguins." In Birds of Australia. Princeton University Press, 2014. http://dx.doi.org/10.1515/9781400865109.100.
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"PENGUINS." In Wildlife Conservation Society Birds of Brazil. Cornell University Press, 2019. http://dx.doi.org/10.7591/9781501704307-020.
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"Penguins." In Phylogeny and Classification of the Birds. Yale University Press, 1991. http://dx.doi.org/10.12987/9780300237856-047.
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Chiaradia, André. "Little Blues: Smallest Penguins Face Big Challenges." In Penguins. Princeton University Press, 2022. http://dx.doi.org/10.1515/9780691233581-013.
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Le Maho, Yvon. "Marking Penguins: Minimising Research Impacts." In Penguins. Princeton University Press, 2022. http://dx.doi.org/10.1515/9780691233581-010.
Full textConference papers on the topic "Penguins"
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De Bruyn, Kristof Antoon M., Robert Fleischer, and Eleftheria Malami. "Taming Penguins: towards high precision measurements of $\phi_d$ and $\phi_s$." In 9th Symposium on Prospects in the Physics of Discrete Symmetries. Sissa Medialab, 2025. https://doi.org/10.22323/1.481.0034.
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Biswas, Aritra. "Penguin decays of B mesons." In 9th Symposium on Prospects in the Physics of Discrete Symmetries. Sissa Medialab, 2025. https://doi.org/10.22323/1.481.0036.
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Noboru, Youta, Yuko Ozasa, and Masayuki Tanaka. "Hyperspectral Image Dataset for Individual Penguin Identification." In IGARSS 2024 - 2024 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2024. http://dx.doi.org/10.1109/igarss53475.2024.10642522.
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Martel, Lucas. "$b \to s$ Penguin results from Belle II." In 20th International Conference on B-Physics at Frontier Machines. Sissa Medialab, 2024. http://dx.doi.org/10.22323/1.443.0008.
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BIJNENS, JOHAN. "PENGUINS 2002: PENGUINS IN K → ππ DECAYS". У Proceedings of the Conference. WORLD SCIENTIFIC, 2002. http://dx.doi.org/10.1142/9789812776310_0001.
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Samuell, Gemma. "BBC ident "Penguins"." In ACM SIGGRAPH 2008 computer animation festival. ACM Press, 2008. http://dx.doi.org/10.1145/1400468.1400478.
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Limet, Sun. "Do penguins fly?" In ACM SIGGRAPH 2008 computer animation festival. ACM Press, 2008. http://dx.doi.org/10.1145/1400468.1400493.
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Conner, Judy. "Halls penguins airport." In ACM SIGGRAPH 97 Visual Proceedings: The art and interdisciplinary programs of SIGGRAPH '97. ACM Press, 1997. http://dx.doi.org/10.1145/259081.259384.
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Walsh, Darren. "BBC iPlayer "Penguins"." In ACM SIGGRAPH ASIA 2008 computer animation festival. ACM Press, 2008. http://dx.doi.org/10.1145/1504271.1504274.
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Hurth, Tobias. "News on penguins." In 19TH PARTICLES AND NUCLEI INTERNATIONAL CONFERENCE (PANIC11). AIP, 2012. http://dx.doi.org/10.1063/1.3700650.
Full textReports on the topic "Penguins"
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Dee Boersma, Dee Boersma. Tracking Magellanic Penguins. Experiment, 2012. http://dx.doi.org/10.18258/0022.
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Eigen, G. RARE DECAYS INCLUDING PENGUINS. Office of Scientific and Technical Information (OSTI), 2003. http://dx.doi.org/10.2172/826589.
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Grossman, yuval. Trojan Penguins and Isospin Violation in Hadronic B Decays. Office of Scientific and Technical Information (OSTI), 1999. http://dx.doi.org/10.2172/12482.
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Brigljevic, Vuko. Study of Charmonium Production and Electroweak Penguins with BABAR. Office of Scientific and Technical Information (OSTI), 2001. http://dx.doi.org/10.2172/798882.
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Clara Maria Wiederkehr Bruno, Clara Maria Wiederkehr Bruno. Do human activities increase antibiotic-resistant disease in Chilean penguins? Experiment, 2022. http://dx.doi.org/10.18258/26653.
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Johannes Fischer, Johannes Fischer. Tracking ‘flying penguins’: pelagic distribution and threats of South Georgia Diving Petrels. Experiment, 2016. http://dx.doi.org/10.18258/7331.
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Dulcinea Groff and Kit Hamley, Dulcinea Groff and Kit Hamley. Penguins, plants, and people: Getting to the core of climate change in the Falkland Islands. Experiment, 2014. http://dx.doi.org/10.18258/3682.
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Eigen, Gerald. RADIATIVE PENGUIN DECAYS FROM BABAR. Office of Scientific and Technical Information (OSTI), 2003. http://dx.doi.org/10.2172/815278.
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Mancinelli, Giampiero. Penguin Mediated B Decays at BaBar. Office of Scientific and Technical Information (OSTI), 2002. http://dx.doi.org/10.2172/801771.
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Jessop, C. STUDIES OF RADIATIVE PENGUIN DECAYS AT BABAR. Office of Scientific and Technical Information (OSTI), 2003. http://dx.doi.org/10.2172/826471.
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