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Penguins

Distribution by Scientific Domains

Life Sciences	78%
Humanities and Social Sciences	11%
3 Other Domains	11%

Distribution within Life Sciences

Ornithology	37%
Conservation Science	16%
Animal Science Methods	11%
Ecology & Organismal Biology	8%
5 Other Subdomains	28%

Kinds of Penguins

king penguin

macaroni penguin

magellanic penguin

Terms modified by Penguins

penguin chick

penguin eudyptula minor

Selected Abstracts

Physiological and Behavioral Differences in Magellanic Penguin Chicks in Undisturbed and Tourist-Visited Locations of a Colony

CONSERVATION BIOLOGY, Issue 5 2005
BRIAN G. WALKER
corticoesterona; ecoturismo; perturbación humana; Spheniscus magellanicus Abstract:,Studies examining anthropogenic effects on wildlife typically focus on adults and on behavioral responses rather than the physiological consequences of human disturbances. Here we examined how Magellanic Penguin ( Spheniscus magellanicus) chicks living in either tourist-visited or undisturbed areas of a breeding colony were affected by human visitation by comparing the baseline and stress-induced levels of corticosterone during three periods of the breeding season. Newly hatched chicks in visited areas had higher corticosterone stress responses than newly hatched chicks in undisturbed areas (p =0.007), but baseline levels were similar (p =0.61). By 40,50 days of age and around fledging time, both visited and undisturbed chicks showed a robust corticosterone stress response to capture. Tourist-visited chicks did not flee when approached by humans, however, whereas undisturbed chicks fled significantly sooner (i.e., when approached no closer than 9 m; p < 0.0001). Although it is unknown whether Magellanic Penguin chicks raised in visited areas suffer negative consequences from the elevation of the corticosterone stress response at hatching, they do exhibit behavioral habituation to human contact by the time they are ready to fledge. Unlike adults living in tourist areas, however, fledging chicks in visited areas do not have a decreased stress response to capture and restraint. Our results show that the coupling of behavioral and physiological habituation in Magellanic Penguins is complex and life-history context may greatly affect the ability of wildlife to adapt to anthropogenic disturbances. Resumen:,Los estudios de los efectos antropogénicos sobre la vida silvestre se centran típicamente en adultos y en las respuestas conductuales en lugar de las consecuencias fisiológicas de las perturbaciones humanas. Aquí examinamos el efecto de la visita de humanos sobre pollos de pingüino (Spheniscus magellanicus) en áreas visitadas por turistas o no perturbadas mediante la comparación de los niveles, base e inducidos por estrés, de corticoesterona durante tres períodos de la temporada reproductiva. Los pollos recién eclosionados en áreas visitadas tuvieron mayor respuesta de la corticoesterona al estrés que los pollos recién eclosionados en áreas no perturbadas (p =0.007), pero los niveles básicos fueron similares (p =0.61). A los 40,50 días y en la etapa de volantón, los pollos visitados y no perturbados mostraron una marcada respuesta de la corticoesterona al estrés al ser capturados. Sin embargo, los pollos visitados por turistas no huyeron cuando se les acercaron humanos, mientras que los pollos no perturbados huyeron significativamente antes (i.e., acercamiento a más de 9 m; p < 0.0001). Aunque se desconoce si los pollos de pingüino criados en áreas visitadas sufren consecuencias negativas por la elevación de la corticosterona en respuesta al estrés al eclosionar, si presentan acostumbramiento conductual al contacto con humanos al momento que están listos para dejar el nido. Sin embargo, a diferencia de adultos que viven en áreas turísticas, los pollos volantones en las áreas visitadas no tienen una disminución en la respuesta al estrés cuando son capturados y sujetados. Nuestros resultados muestran la complejidad de la combinación del acostumbramiento conductual y fisiológico en Spheniscus magellanicus y que el contexto de la historia de vida puede afectar a la habilidad de la vida silvestre para adaptarse a las perturbaciones antropogénicas. [source]

Instructional Pragmatics: Bridging Teaching, Research, and Teacher Education

LINGUISTICS & LANGUAGE COMPASS (ELECTRONIC), Issue 10 2010
Noriko Ishihara
Pragmatics deals with meaning in context that is the meaning conveyed often indirectly beyond what is literally communicated. Ever since Hymes (1972, Sociolinguistics: Selected readings, Penguin, Harmondsworth, England, 269,93) highlighted the importance of socially appropriate language use, ability to use language in context has been identified as an essential component of communicative competence (e.g., Canale and Swain, 1980, Applied Linguistics, 1: 1,47; Canale, 1983, Language and communication, Longman, Harlow; Bachman, 1990, Fundamental considerations in language testing, Oxford University Press, Oxford; Bachman & Palmer, 1996, Language testing in practice: Designing and developing useful language tests, Oxford University Press, Oxford; Celce-Murcia, 2008, Intercultural language use and language learning, Springer, The Netherlands, 41,58; Celce-Murcia et al. 1995, Issues in Applied Linguistics, 6: 5,35), and there has been rigorous research investigating the pragmatic competence of second/foreign language (L2) learners. This paper aims to provide an overview of research conducted in the area of interlanguage pragmatics with a focus on its pedagogical component, instructional pragmatics. The primary emphasis of this paper will be placed on the introduction of current resources in instructional pragmatics and recent efforts that empirically inform pragmatic-focused instruction and classroom-based assessment. The paper concludes with the discussion of the issues associated with future pragmatics-focused instruction and curriculum development, along with a suggested direction for future research and teacher education in support of instructional pragmatics. [source]

Shakespearean Editing and Why It Matters

LITERATURE COMPASS (ELECTRONIC), Issue 1 2005
Leah Marcus
A generation ago, many Shakespearean scholars simply accepted the versions of the play that they were provided with by editors. So long as the label was right , Arden, Oxford, Cambridge, Penguin, Riverside, Pelican , the content was assumed to be reliable. But editing can never be transparent , it is always influenced by the cultural assumptions of the editor and his or her era, however submerged those assumptions may be in terms of the editor's stated textual practices. In the late twentieth and twenty-first centuries, as a result of feminist and postcolonial critical approaches to Shakespearean texts, we have begun to realize the degree to which our inherited editions are shaped in accordance with assumptions about colonialism, race, and the status of women that are no longer acceptable to us, and that in fact distort elements of Shakespeare's plays as they exist in early printed quarto and folio versions. As earlier disciplinary boundaries between editing and criticism have broken down, Shakespearean critics have increasingly turned to editing in order to undo some of the racist and sexist assumptions behind our received texts of the plays. [source]

Political Theology, Political Religion and Secularisation

POLITICAL STUDIES REVIEW, Issue 2 2010
Richard Shorten
Burleigh, M. (2005) Earthly Powers: Religion and Politics in Europe from the French Revolution to the Great War. London: HarperCollins. Burleigh, M. (2006) Sacred Causes: Religion and Politics from the European Dictators to Al Qaeda. London: HarperPress. Gentile, E. (2006) Politics as Religion. Princeton NJ: Princeton University Press. Gray, J. (2007) Black Mass: Apocalyptic Religion and the Death of Utopia. London: Penguin. Lilla, M. (2007) The Stillborn God: Religion, Politics and the Modern West. New York: Knopf. [source]

Fine structural dependence of ultraviolet reflections in the King Penguin beak horn

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 3 2006
Birgitta Dresp
Abstract The visual perception of many birds extends into the near-ultraviolet (UV) spectrum and ultraviolet is used by some to communicate. The beak horn of the King Penguin (Aptenodytes patagonicus) intensely reflects in the ultraviolet and this appears to be implicated in partner choice. In a preliminary study, we recently demonstrated that this ultraviolet reflectance has a structural basis, resulting from crystal-like photonic structures, capable of reflecting in the near-UV. The present study attempted to define the origin of the photonic elements that produce the UV reflectance and to better understand how the UV signal is optimized by their fine structure. Using light and electron microscopic analysis combined with new spectrophotometric data, we describe here in detail the fine structure of the entire King Penguin beak horn in addition to that of its photonic crystals. The data obtained reveal a one-dimensional structural periodicity within this tissue and demonstrate a direct relationship between its fine structure and its function. In addition, they suggest how the photonic structures are produced and how they are stabilized. The measured lattice dimensions of the photonic crystals, together with morphological data on its composition, permit predictions of the wavelength of reflected light. These correlate well with experimentally observed values. The way the UV signal is optimized by the fine structure of the beak tissue is discussed with regard to its putative biological role. © 2006 Wiley-Liss, Inc. [source]

Physiological and Behavioral Differences in Magellanic Penguin Chicks in Undisturbed and Tourist-Visited Locations of a Colony

Penguins as oceanographers unravel hidden mechanisms of marine productivity

ECOLOGY LETTERS, Issue 3 2002
Jean-Benoît Charrassin
ABSTRACT A recent concept for investigating marine ecosystems is to employ diving predators as cost-effective, autonomous samplers of environmental parameters (such as sea-temperature). Using king penguins during their foraging trips at sea, we obtained an unprecedented high resolution temperature map at depth off the Kerguelen Islands, Southern Ocean, a poorly sampled but productive area. We found clear evidence of a previously unknown subsurface tongue of cold water, flowing along the eastern shelf break. These new results provide a better understanding of regional water circulation and help explain the high primary productivity above the Kerguelen Plateau. [source]

Penguin responses to climate change in the Southern Ocean

GLOBAL CHANGE BIOLOGY, Issue 7 2009
JAUME FORCADA
Abstract Penguins are adapted to live in extreme environments, but they can be highly sensitive to climate change, which disrupts penguin life history strategies when it alters the weather, oceanography and critical habitats. For example, in the southwest Atlantic, the distributional range of the ice-obligate emperor and Adélie penguins has shifted poleward and contracted, while the ice-intolerant gentoo and chinstrap penguins have expanded their range southward. In the Southern Ocean, the El Niño-Southern Oscillation and the Southern Annular Mode are the main modes of climate variability that drive changes in the marine ecosystem, ultimately affecting penguins. The interaction between these modes is complex and changes over time, so that penguin responses to climate change are expected to vary accordingly, complicating our understanding of their future population processes. Penguins have long life spans, which slow microevolution, and which is unlikely to increase their tolerance to rapid warming. Therefore, in order that penguins may continue to exploit their transformed ecological niche and maintain their current distributional ranges, they must possess adequate phenotypic plasticity. However, past species-specific adaptations also constrain potential changes in phenology, and are unlikely to be adaptive for altered climatic conditions. Thus, the paleoecological record suggests that penguins are more likely to respond by dispersal rather than adaptation. Ecosystem changes are potentially most important at the borders of current geographic distributions, where penguins operate at the limits of their tolerance; species with low adaptability, particularly the ice-obligates, may therefore be more affected by their need to disperse in response to climate and may struggle to colonize new habitats. While future sea-ice contraction around Antarctica is likely to continue affecting the ice-obligate penguins, understanding the responses of the ice-intolerant penguins also depends on changes in climate mode periodicities and interactions, which to date remain difficult to reproduce in general circulation models. [source]

Is food availability limiting African Penguins Spheniscus demersus at Boulders?

IBIS, Issue 1 2006
A comparison of foraging effort at mainland, island colonies
The African Penguin Spheniscus demersus (Vulnerable) formed three new colonies during the 1980s, two on the South African mainland (Stony Point and Boulders) and one on Robben Island. One of the mainland colonies, at Boulders, Simon's Town, is in a suburban area, resulting in conflict with humans. Growth of the Boulders colony was initially rapid, largely through immigration, but has since slowed, possibly as a result of density-dependent effects either on land (where there has been active management to limit the spread of the colony) or at sea. We test the latter hypothesis by comparing the foraging effort of Penguins feeding small chicks at island and mainland sites, and relate this to the foraging area available to birds. Three-dimensional foraging paths of African Penguins were reconstructed using GPS and time,depth loggers. There were no intercolony differences in the rate at which birds dived during the day (33 dives/h), in diving depths (mean 17 m, max. 69 m) or in travelling speeds. The maximum speed recorded was 2.85 m/s, with birds travelling faster when commuting (average 1.18 m/s) than when foraging (0.93 m/s) or resting at sea (0.66 m/s during the day, 0.41 m/s at night). There were strong correlations between foraging trip duration, foraging range and total distance travelled. Foraging effort was correlated with chick age at Robben Island, but not at Boulders. Contrary to Ashmole's hypothesis, birds from Boulders (c. 1000 pairs) travelled further (46,53 km) and foraged for longer (13.2 h) than did birds from Robben Island (c. 7000 pairs) and Dassen Island (c. 21 000 pairs) (33 km, 10.3 h). The mean foraging range also differed significantly between mainland (18,20 km) and island colonies (9 km). The area available to central-place-foraging seabirds breeding on the mainland is typically less than that for seabirds breeding on islands, but the greater foraging range of Boulders birds results in an absolute foraging area roughly twice that of island colonies, and the area per pair is an order of magnitude greater for the relatively small Boulders colony. Ashmole's hypothesis assumes relatively uniform prey availability among colonies, but our results suggest this does not apply in this case. The greater foraging effort of Boulders birds probably reflects reduced prey availability in False Bay, and thus the recent slowing in growth at the colony may be the result of differential immigration rather than management actions to limit the spatial growth of the colony. [source]

Differences in egg size, shell thickness, pore density, pore diameter and water vapour conductance between first and second eggs of Snares Penguins Eudyptes robustus and their influence on hatching asynchrony

IBIS, Issue 2 2005
MELANIE MASSARO
Brood reduction in birds is frequently induced by hatching asynchrony. Crested penguins (genus Eudyptes) are obligate brood reducers, but in contrast to most other birds, first-laid eggs are considerably smaller in size than second-laid eggs; furthermore, first-laid eggs hatch after their siblings. The mechanisms underlying this reversal in size and hatching order remain unclear. In this study, we tested whether the second-laid eggs of Snares Penguins Eudyptes robustus have a higher eggshell porosity allowing them to maintain a higher metabolic rate throughout incubation and to hatch before their first-laid siblings. We investigated differences in egg size, shell thickness, pore density, pore diameter and water vapour conductance between first and second eggs within clutches and examined the influence of these shell characteristics on hatching asynchrony. First-laid eggs of Snares Penguins were approximately 78% of the size of the larger second eggs. Second-laid eggs had considerably thicker shells and more pores per cm2 than first eggs, whereas pore diameter did not differ between eggs. Water vapour conductance was greater in second- (16.8 mg/day/torr) than in first-laid eggs (14.9 mg/day/torr). The difference in water vapour conductance between first- and second-laid eggs within clutches was related to hatching patterns. In nests where second eggs hatched before first-laid eggs, second eggs had a considerably greater water conductance than their sibling, whereas in nests where both eggs hatched on the same day, the difference in water conductance between eggs was very small, and in a few nests where small first eggs hatched before their larger sibling, they had a greater water conductance than their larger second-laid nestmate. Surprisingly few studies have investigated differences in shell characteristics between eggs within clutches and associated effects on hatching asynchrony. This study has demonstrated that such differences exist between eggs within clutches and that they can influence hatching patterns. [source]

Of squeezers and skippers: factors determining the age at moult of immature African Penguins Spheniscus demersus in Namibia

IBIS, Issue 2 2005
JESSICA KEMPER
We used banding and resighting records of 391 African Penguins Spheniscus demersus banded as chicks and later resighted during immature moult to explain the roles of date of fledging and age at moult in determining the season of moult and its timing within the season. Breeding was continuous, but immature moult occurred mainly during spring and summer. Age at immature moult extended over 11 months, from 12 to 23 months after hatching. Birds that fledged during summer and early autumn generally moulted during the next moult season (squeezers), whereas birds that fledged in late autumn, winter and spring skipped the next moult season to moult only the following season (skippers). There was a significant relationship between age at moult and moult date, with young birds moulting later in the season than older birds. The age at moult of immature birds appears to be constrained by minimum age, moult seasonality and plumage wear. Birds that fledged over nearly 2 years moult during one season. Counts of moulting immature African Penguins have not been used to estimate year-class strength and post-fledging survival owing to the wide range of ages at immature moult. Our results provide the means of assigning recruits to specific age groups. [source]

Restoration of body mass in King Penguins after egg abandonment at a critical energy depletion stage: early vs late breeders

JOURNAL OF AVIAN BIOLOGY, Issue 4 2001
Jean-Patrice Robin
In fasting-incubating seabirds, it has been proposed that egg abandonment and refeeding should be induced when a low body mass (BM) threshold is attained, thus ensuring adult survival at the expense of immediate breeding. In the context of life-history trade-offs in long-lived birds, we have tested this hypothesis by comparing short-term survival and restoration of BM in King Penguins Aptenodytes patagonicus that abandoned their egg to those that were relieved normally by their mate at the end of the first incubation shift. Since King Penguins have an extended laying period, the possible influence of seasonal factors was also examined by comparing early and late breeders. Forty incubating males were experimentally forced to fast until egg abandonment by preventing relief by the female. At egg abandonment of both early and late breeding males, BM was below the BM threshold, fasting duration was eight days (about 30%) longer than for relieved birds, and plasma uric acid level was elevated (signature of increased body protein catabolism, phase III of fasting). All abandoning birds survived and came back from sea at a BM similar to that of relieved penguins. The duration of the foraging trip of abandoning early breeders was the same as that of relieved birds, and some abandoning birds engaged in a new breeding attempt. Abandoning late breeders, however, made foraging trips twice as long as those of relieved males. This difference can be explained by time constraints rather than nutritional constraints, abandoning early breeders having enough time left in the breeding season to engage in a new breeding attempt in contrast to abandoning late breeders. These observations lend support to the suggestion that not only BM but also an internal clock intervene in the decision to engage in breeding or not. By preventing a lethal energy depletion ashore and by acting at a fasting stage where the capacity to restore BM at sea is unaffected, abandonment at a low body condition threshold plays a major role in the trade-off between adult penguin survival and reproduction. [source]

Flipper bands do not affect foraging-trip duration of Magellanic Penguins

JOURNAL OF FIELD ORNITHOLOGY, Issue 4 2009
P. Dee Boersma
ABSTRACT Flipper bands are used to mark penguins because leg bands can injure their legs. However, concerns remain over the possible effects of flipper bands on penguins. We examined the effects of stainless-steel flipper bands on the duration of foraging trips by Magellanic Penguins (Spheniscus magellanicus) at Punta Tombo, Argentina, using an automated detection system. We predicted that, if bands were costly and increased drag, flipper-banded penguins would make longer foraging trips than those with small or no external markings. We tagged 121 penguins with radio-frequency identification (RFID) tags and an additional external mark. We placed either a stainless-steel band on the left flipper (N= 62) or a 2×10-mm small-animal ear tag in the outside web of the left foot (N= 59). We measured foraging-trip durations (N= 376 trips) for 68 adult penguins with chicks from 15 December 2007 to 28 February 2008. Contrary to predictions, trip duration was similar for banded and web-tagged penguins (P= 0.22) and for males and females (P= 0.52), with no interaction between tag type and sex (P= 0.52). No penguins marked in the 2007 breeding season and recaptured between 30 September and 30 November 2008 (N= 113) lost flipper bands or web tags, but three RFID tags failed between March and September 2008. Properly designed and applied flipper bands were a reliable marking method for Magellanic Penguins, had a lower failure rate than RFIDs, and did not affect foraging-trip duration. RESUMEN Los anillos de ala son usados para marcar pingüinos porque los anillos de tarso pueden causar heridas en sus piernas. Sin embargo, existen dudas sobre los posibles efectos de los anillos de ala sobre los pingüinos. Usando un sistema de detección automatizado, examinamos los efectos de anillos de ala hechos de acero inoxidable sobre la duración de los viajes para forrajeo por el pingüino Spheniscus magellanicus en Punta Tombo, Argentina. Predecimos que si los anillos afectarían a los pingüinos e incrementaran la fricción con el agua, los pingüinos con anillos de ala harían viajes para forrajeo de mayor duración en comparación a los que no portaban marcadores externos o que llevaban marcadores externos de menor tamaño. Marcamos a 121 pingüinos con marcadores de identificación por radio frecuencia, además de otro marcador al exterior del ave. Colocamos un anillo de acero inoxidable al ala izquierdo (N= 62), o un marcador de oreja (2×10 mm) para animales pequeños de en la membrana interdigital exterior del pie izquierdo (N= 59). Desde el 15 de diciembre del 2007 hasta el 28 de Febrero del 2008 medimos la duración de los viajes para forrajeo (N= 376 viajes) para 68 pingüinos adultos con pichones. Contrariamente a nuestras predicciones, la duración de los viajes fue similar para pingüinos con anillos y para pingüinos con marcadores en el pie (P = 0.22), así como entre machos y hembras (P= 0.52), con ninguna interacción entre el tipo de marca y el sexo (P= 0.52). Ningún pingüino marcado en la temporada reproductiva del 2007 y recapturado entre el 30 de Septiembre y el 30 de Noviembre del 2008 (N= 113) perdió el anillo de ala o el marcador en el pie, pero tres marcadores de identificación por radio frecuencia fallaron entre Marzo y Septiembre del 2008. Los anillos de ala apropiadamente diseñadas y aplicadas fueron un método de marcaje confiable para S. magellanicus, tuvieron una tasa de fallo menor a los marcadores de identificación por radio frecuencia y no afectaron a la duración de los viajes para forrajeo. [source]

Bacteria divert resources from growth for magellanic penguin chicks

ECOLOGY LETTERS, Issue 6 2002
Jaime Potti
Abstract The influence of bacteria on the growth of their wild avian hosts is unknown. We tested experimentally whether administration of a wide-spectrum antibiotic (cephalosporine) during early development of magellanic penguin (Spheniscus magellanicus) chicks had any effect on their growth rates in the wild. Chicks that were injected in two occasions with cephalosporine grew faster than control untreated chicks. The positive effect of medication on nestling growth disappeared after the treatment ceased, did not alter haematological indices indicative of health status, had no influence on chick survival until near independence and was related to a changed bacterial composition of the faecal microbiota of treated chicks when compared with that from control chicks. These results were similar to those obtained for poultry with antimicrobials promoting growth and chick nutrient assimilation rates. Gram-positive bacilli in the diphtheroid genus Corynebacterium are likely candidates to cause decreased growth rates in magellanic penguin chicks. [source]

Production of Designer Mabe Pearls in the Black-lipped Pearl Oyster, Pinctada margaritifera, and the Winged Pearl Oyster, Pteria penguin, from Andaman and Nicobar Islands, India

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2008
V. Kripa
[source]

Limitation of population recovery: a stochastic approach to the case of the emperor penguin

OIKOS, Issue 9 2009
Stéphanie Jenouvrier
Major population crashes due to natural or human-induced environmental changes may be followed by recoveries. There is a growing interest in the factors governing recovery, in hopes that they might guide population conservation and management, as well as population recovery following a re-introduction program. The emperor penguin Aptenodytes forsteri population in Terre Adélie, Antarctica, declined by 50% during a regime shift in the mid-1970s, when abrupt changes in climate and ocean environment regimes affected the entire Southern Ocean ecosystem. Since then the population has remained stable and has not recovered. To determine the factors limiting recovery, we examined the consequences of changes in survival and breeding success after the regime shift. Adult survival recovered to its pre-regime shift level, but the mean breeding success declined and the variance in breeding success increased after the regime shift. Using stochastic matrix population models, we found that if the distribution of breeding success observed prior to the regime shift had been retained, the emperor penguin population would have recovered, with a median time to recovery of 36 years. The observed distribution of breeding success after the regime shift makes recovery very unlikely. This indicates that the pattern of breeding success is sufficient to have prevented emperor penguin population recovery. The population trajectory predicted on the basis of breeding success agrees with the observed trajectory. This suggests that the net effect of any facors other than breeding success must be small. We found that the probability of recovery and the time to recovery depend on both the mean and variance of breeding success. Increased variance in breeding success increases the probability of recovery when mean success is low, but has the opposite effect when the mean is high. This study shows the important role of breeding success in determining population recovery for a long-lived species and demonstrates that demographic mechanisms causing population crash can be different from those preventing population recovery. [source]

Stable isotope natural abundance of nitrous oxide emitted from Antarctic tundra soils: effects of sea animal excrement depositions

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2008
Renbin Zhu
Nitrous oxide (N2O), a greenhouse gas, is mainly emitted from soils during the nitrification and denitrification processes. N2O stable isotope investigations can help to characterize the N2O sources and N2O production mechanisms. N2O isotope measurements have been conducted for different types of global terrestrial ecosystems. However, no isotopic data of N2O emitted from Antarctic tundra ecosystems have been reported although the coastal ice-free tundra around Antarctic continent is the largest sea animal colony on the global scale. Here, we report for the first time stable isotope composition of N2O emitted from Antarctic sea animal colonies (including penguin, seal and skua colonies) and normal tundra soils using insitu field observations and laboratory incubations, and we have analyzed the effects of sea animal excrement depositions on stable isotope natural abundance of N2O. For all the field sites, the soil-emitted N2O was 15N- and 18O-depleted compared with N2O in local ambient air. The mean , values of the soil-emitted N2O were ,15N,=,,13.5,±,3.2, and ,18O,=,26.2,±,1.4, for the penguin colony, ,15N,=,,11.5,±,5.1, and ,18O,=,26.4,±,3.5, for the skua colony and ,15N,=,,18.9,±,0.7, and ,18O,=,28.8,±,1.3, for the seal colony. In the soil incubations, the isotopic composition of N2O was measured under N2 and under ambient air conditions. The soils incubated under the ambient air emitted very little N2O (2.93,µg,N2ON,kg,1). Under N2 conditions, much more N2O was formed (9.74,µg,N2ON,kg,1), and the mean ,15N and ,18O values of N2O were ,19.1,±,8.0, and 21.3,±,4.3,, respectively, from penguin colony soils, and ,17.0,±,4.2, and 20.6,±,3.5,, respectively, from seal colony soils. The data from in situ field observations and laboratory experiments point to denitrification as the predominant N2O source from Antarctic sea animal colonies. Copyright © 2008 John Wiley & Sons, Ltd. [source]

The structural mechanics and evolution of aquaflying birds

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2010
MICHAEL HABIB
Mass-specific bone strength was examined in the forelimb and hindlimb of 64 species of birds to determine if aquaflying birds (which utilize the wings for propulsion underwater) differ in their skeletal strength compared with other avian taxa. Long bone strengths were estimated from cross-sectional measurements. Compared with the expectation from geometric similarity, humeral section modulus in volant birds scales nearly isometrically, while femoral strength scales with significant positive allometry. Penguin mass-specific humeral strength is greatly elevated, but the average humeral strength in species that are propelled by the wings in both air and water do not differ from the values calculated in non-diving taxa. However, amphibious flyers have gracile femora. Comparative analyses using independent contrasts were utilized to examine the impact of phylogenetic signal. The residual measured for the penguin,procellariiform humeral strength contrast was larger in magnitude (residual of 2.14) than at any other node in the phylogeny. The data strongly indicate that the transition from an amphibious flight condition to a fully aquatic condition involves greater changes in mechanical factors than the transition from purely aerial locomotion to amphibious wing use. There remains the possibility that a historical effect, such as ancestral body size, has impacted the mechanical scaling of penguins. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 687,698. [source]

Penguins as oceanographers unravel hidden mechanisms of marine productivity

Penguin responses to climate change in the Southern Ocean

Contrasting population changes in sympatric penguin species in association with climate warming

GLOBAL CHANGE BIOLOGY, Issue 3 2006
JAUME FORCADA
Abstract Climate warming and associated sea ice reductions in Antarctica have modified habitat conditions for some species. These include the congeneric Adélie, chinstrap and gentoo penguins, which now demonstrate remarkable population responses to regional warming. However, inconsistencies in the direction of population changes between species at different study sites complicate the understanding of causal processes. Here, we show that at the South Orkney Islands where the three species breed sympatrically, the less ice-adapted gentoo penguins increased significantly in numbers over the last 26 years, whereas chinstrap and Adélie penguins both declined. These trends occurred in parallel with regional long-term warming and significant reduction in sea ice extent. Periodical warm events, with teleconnections to the tropical Pacific, caused cycles in sea ice leading to reduced prey biomass, and simultaneous interannual population decreases in the three penguin species. With the loss of sea ice, Adélie penguins were less buffered against the environment, their numbers fluctuated greatly and their population response was strong and linear. Chinstrap penguins, considered to be better adapted to ice-free conditions, were affected by discrete events of locally increased ice cover, but showed less variable, nonlinear responses to sea ice loss. Gentoo penguins were temporarily affected by negative anomalies in regional sea ice, but persistent sea ice reductions were likely to increase their available niche, which is likely to be substantially segregated from that of their more abundant congeners. Thus, the regional consequences of global climate perturbations on the sea ice phenology affect the marine ecosystem, with repercussions for penguin food supply and competition for resources. Ultimately, variability in penguin populations with warming reflects the local balance between penguin adaptation to ice conditions and trophic-mediated changes cascading from global climate forcing. [source]

Alteration of the food web along the Antarctic Peninsula in response to a regional warming trend

GLOBAL CHANGE BIOLOGY, Issue 12 2004
Mark A. Moline
Abstract In the nearshore coastal waters along the Antarctic Peninsula, a recurrent shift in phytoplankton community structure, from diatoms to cryptophytes, has been documented. The shift was observed in consecutive years (1991,1996) during the austral summer and was correlated in time and space with glacial melt-water runoff and reduced surface water salinities. Elevated temperatures along the Peninsula will increase the extent of coastal melt-water zones and the seasonal prevalence of cryptophytes. This is significant because a change from diatoms to cryptophytes represents a marked shift in the size distribution of the phytoplankton community, which will, in turn, impact the zooplankton assemblage. Cryptophytes, because of their small size, are not grazed efficiently by Antarctic krill, a keystone species in the food web. An increase in the abundance and relative proportion of cryptophytes in coastal waters along the Peninsula will likely cause a shift in the spatial distribution of krill and may allow also for the rapid asexual proliferation of carbon poor gelatinous zooplankton, salps in particular. This scenario may account for the reported increase in the frequency of occurrence and abundance of large swarms of salps within the region. Salps are not a preferred food source for organisms that occupy higher trophic levels in the food web, specifically penguins and seals, and thus negative feedbacks to the ecology of these consumers can be anticipated as a consequence of shifts in phytoplankton community composition. [source]

Differences in egg size, shell thickness, pore density, pore diameter and water vapour conductance between first and second eggs of Snares Penguins Eudyptes robustus and their influence on hatching asynchrony

Transposition of line-length discrimination in African penguins (Spheniscus demersus),

JAPANESE PSYCHOLOGICAL RESEARCH, Issue 3 2009
KAZUCHIKA MANABE
Abstract Four penguins (Spheniscus demersus) were trained to discriminate line length in a simultaneous discrimination task. After the birds' performances reached a discrimination criterion, the reinforcement ratio was decreased to .33. After the ratio of correct trials reached .90 in three successive sessions with a partial reinforcement procedure, probe-test sessions were introduced. In the probe-test trials, untrained lines were presented paired with the trained lines. The four probe-test trials were mixed into 45 discrimination trials. In the probe-test trials, the penguins that had been trained to peck shorter lines pecked the untrained shorter line rather than the longer line that was reinforced in the discrimination trials. In contrast, those birds that had been trained to peck the longer line pecked the untrained longer line, rather than the shorter line which was reinforced in the discrimination trials. All four birds demonstrated transposition in the line-length discrimination task. [source]

Estimating food consumption of marine predators: Antarctic fur seals and macaroni penguins

JOURNAL OF APPLIED ECOLOGY, Issue 1 2002
I.L. Boyd
Summary 1Estimating food consumption is central to defining the ecological role of marine predators. This study developed an algorithm for synthesizing information about physiology, metabolism, growth, diet, life history and the activity budgets of marine predators to estimate population energy requirements and food consumption. 2Two species of marine predators (Antarctic fur seal Arctocephalus gazella and macaroni penguin Eudyptes chrsolophus) that feed on krill in the Southern Ocean were used as examples to test the algorithm. A sensitivity analysis showed that estimates of prey consumed were most sensitive to uncertainty in some demographic variables, particularly the annual survival rate and total offspring production. Uncertainty in the measurement of metabolic rate led to a positive bias in the mean amount of food consumed. Uncertainty in most other variables had little influence on the estimated food consumed. 3Assuming a diet mainly of krill Euphausia superba, annual food consumption by Antarctic fur seals and macaroni penguins at the island of South Georgia was 3·84 [coefficient of variation (CV) = 0·11] and 8·08 (CV = 0·23) million tonnes, respectively. This was equivalent to a total annual carbon consumption of 0·35 (CV = 0·11) and 0·72 (CV = 0·23) G tonnes year,1. Carbon expired as CO2 was 0·26 (CV = 0·06) and 0·65 (CV = 0·19) G tonnes year,1 for fur seals and macaroni penguins, respectively. The per capita food consumption varied depending upon sex and age but, overall, this was 1·7 (CV = 0·22) tonnes year,1 for Antarctic fur seals and 0·45 (CV = 0·22) tonnes year,1 for macaroni penguins. 4The algorithm showed that the seasonal demand for food peaked in both species in the second half of the breeding season and, for macaroni penguins, there was a second peak immediately after moult. Minimum food demand occurred in both species during the first half of the breeding season. 5As both Antarctic fur seals and macaroni penguins compete for krill with a commercial fishery, these results provide an insight into the seasons and stages of the life cycle in which competition is likely to be greatest. [source]

The double vocal signature of crested penguins: is the identity coding system of rockhopper penguins Eudyptes chrysocome due to phylogeny or ecology?

JOURNAL OF AVIAN BIOLOGY, Issue 5 2005
Amanda Searby
Parent-offspring recognition systems are used in bird colonies to avoid misdirected parental care. In penguins, where the risk of confusion is particularly high, recognition is achieved by acoustic signals that constitute highly efficient vocal signatures. Comparisons between species from the Pygoscelis and Aptenodytes genera have revealed interspecific differences on the encoding of information within the signatures which correlate with the presence/absence of nests in the colonies. However a recent study of individual recognition in macaroni penguins Eudyptes chrysolophus revealed diversity within nest-building species. This paper investigates whether the original and intermediate signature system found in macaroni penguins is shared by another species of Eudyptes, the rockhopper penguin E. chrysocome. Vocal signatures of rockhopper penguins were analysed and compared to macaroni penguins'. We used a methodology derived from the theory of information to determine which parameters of the call were likely to encode individual identity. Playbacks of modified calls in the field complemented the analyses, and parent-chick reunions were compared between the two species. Our results reveal a similar double signature system within the Eudyptes genus, which integrates information simultaneously from the temporal and spectral domains. This double encoding is made through the tempo given by the successive syllables of the call and the harmonic content of the call. While it confirms the hypothesis that signatures are simpler in nest-building species, this result reveals differences in the efficacies of signatures within this category. This suggests that other parameters such as the mean distance recognition should be considered to account for the differences in the encoding of the vocal signatures and in their resulting efficacies. [source]

Tufted ducks Aythya fuligula do not control buoyancy during diving

JOURNAL OF AVIAN BIOLOGY, Issue 3 2005
Lewis G. Halsey
Work against buoyancy during submergence is a large component of the energy costs for shallow diving ducks. For penguins, buoyancy is less of a problem, however they still seem to trade-off levels of oxygen stores against the costs and benefits of buoyant force during descent and ascent. This trade-off is presumably achieved by increasing air sac volume and hence pre-dive buoyancy (Bpre) when diving deeper. Tufted ducks, Aythya fuligula, almost always dive with nearly full oxygen stores so these cannot be increased. However, the high natural buoyancy of tufted ducks guarantees a passive ascent, so they might be expected to decrease Bpre before particularly deep, long dives to reduce the energy costs of diving. Body heat lost to the water can also be a cause of substantial energy expenditure during a dive, both through dissipation to the ambient environment and through the heating of ingested food and water. Thus dive depth (dd), duration and food type can influence how much heat energy is lost during a dive. The present study investigated the relationship between certain physiological and behavioural adjustments by tufted ducks to dd and food type. Changes in Bpre, deep body temperature (Tb) and dive time budgeting of four ducks were measured when diving to two different depths (1.5 and 5.7 m), and for two types of food (mussels and mealworms). The hypothesis was that in tufted ducks, Bpre decreases as dd increases. The ducks did not change Bpre in response to different diving depths, and thus the hypothesis was rejected. Tb was largely unaffected by dives to either depth. However, diving behaviour changed at the greater dd, including an increase in dive duration and vertical descent speed. Behaviour also changed depending on the food type, including an increase in foraging duration and vertical descent speed when mussels were present. Behavioural changes seem to represent the major adjustment made by tufted ducks in response to changes in their diving environment. [source]

Effects of long-term implanted data loggers on macaroni penguins Eudyptes chrysolophus

JOURNAL OF AVIAN BIOLOGY, Issue 4 2004
Jonathan A. Green
We tested the hypothesis that implanted data loggers have no effect on the survival, breeding success and behaviour of macaroni penguins Eudyptes chrysolophus. Seventy penguins were implanted with heart rate data loggers (DLs) for periods of up to 15 months. When compared to control groups, implanted penguins showed no significant difference in over-wintering survival rates, arrival date and mass at the beginning of the breeding season. Later in the breeding season, implanted penguins showed no significant difference in the duration of their incubation foraging trip, breeding success, fledging mass of their chicks, date of arrival to moult and mass at the beginning of the moult fast. We conclude that implanted devices had no effects on the behaviour, breeding success and survival of this species. We contrast these results to those from studies using externally attached devices, which commonly affect the behaviour of penguins. We suggest that implanted devices should be considered as an alternative to externally attached devices in order to obtain the most accurate representation of the free-ranging behaviour, ecology and physiology of penguins. [source]

Increased survival and breeding performance of double breeders in little penguins Eudyptula minor, New Zealand: evidence for individual bird quality?

JOURNAL OF AVIAN BIOLOGY, Issue 2 2003
Edda Johannesen
The little penguin Eudyptula minor is unique among penguin species in being able to fledge chicks from two clutches in one breeding season. Pairs laying two clutches in a given season make a higher reproductive investment, and may be rewarded by a higher reproductive success as they may raise twice as many chicks as pairs laying one clutch. The higher effort made by pairs laying two clutches could correlate negatively with survival, future reproductive performance or offspring survival, indicating a cost of reproduction. Conversely, a positive relationship between the number of clutches produced in a given breeding season and survival, future reproductive performance or offspring survival would indicate that birds laying two clutches belonged to a category of birds with higher fitness, compared to birds laying only one clutch in the season. In this study we used a long-term data set taken from an increasing population of little penguins in Otago, SE New Zealand. We modelled the relationship between the number of clutches laid in a breeding season and survival probability, reproductive performance in the next breeding season and first year survival of offspring using capture-recapture modelling. Birds laying two clutches produced 1.7 times more fledglings during a breeding season than pairs laying one clutch. We found that birds laying two clutches had a higher probability of breeding in the following breeding season, a higher probability of laying two clutches in the following breeding season and a higher survival probability. There was no overall difference in post-fledging survival between the young of birds producing one clutch and the young of birds producing two clutches. However, the survival of young of single clutch breeders declined with laying date, whereas the young of double clutch breeders had the same survival rate irrespective of laying date. For a subset of data with birds of known age, we found evidence that the probability of laying two clutches increased with age. However, there were also indications for differences among birds in the tendency to lay two clutches that could not be attributed to age. We tentatively interpret our results as evidence of quality difference among little penguin breeders. [source]