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The emperor penguin (Aptenodytes forsteri) is the largest extant penguin among living species breeding in winter, at Antarctic high latitudes. Despite several studies made on this species, musculature and skeletal anatomy are barely known, especially in non-adult specimens. To address this shortfall, dissections and comparative descriptions were made on crania and mandibles of individuals of different ontogenetic stages: chicks, juveniles, and adults. The results presented here show significant differences in musculature between the age groups, and the proportions between bill and cranium also change along postnatal ontogeny., Facultad de Ciencias Naturales y Museo

The King Penguin (Aptenodytes patagonicus) is a pelagic seabird that breeds on Subantarctic islands and is considered a rare vagrant in South Africa. From 2001 to 2017, six King Penguins were rescued along the South African coast and admitted into rehabilitation centers. These and previous records of King Penguins were obtained near the country’s major ports, which suggests that some of these birds may have been ship-assisted. One of the King Penguins evaluated in this study died shortly after being admitted to the rehabilitation center due to extensive hemorrhage caused by a long-line fishing hook, and another had a beak wound consistent with fishing hook injury. Three King Penguins were infected with the tick-borne protozoan Babesia peircei and two died as a result of babesiosis. One King Penguin was diagnosed with an infection by Rickettsia-like organisms. Pox-like lesions, presumably mosquito-borne, developed on the eyelid skin of one penguin. Additionally, one of two King Penguins permanently captive in Cape Town during the same period also presented a lethal case of spirochetosis, which was possibly tick-borne. These novel records of vector-borne pathogens in King Penguins highlight the risk of seabird rehabilitation centers to serve as potential sources of pathogens to vagrant species, while also illustrating the opportunities that these centers provide for pathogen research and surveillance.

Plumage aberrations, such as leucism, isabellinism, albinism and melanism, are hereditary and are caused by irregularities in the formation of melanin. This paper presents opportunistic observations of plumage aberrations in 15 Macaroni Penguins Eudyptes chrysolophus at sub-Antarctic Marion Island during 2008–2016. Across five colonies, full and partial leucism, isabellinism and partial melanism were recorded. Plumage aberration in Macaroni Penguins is rarely reported elsewhere in the world. The relatively high number of recorded individuals at Marion Island, in conjunction with limited mixing between global Macaroni Penguin colonies, suggests that a relatively high proportion of the population is entrained with this genetic predisposition.

Knowledge of diet is critical in interpreting the ecological roles of marine top predators and provides information towards their conservation and management. The Falkland Islands hold the largest number of breeding gentoo penguins. Yet knowledge of gentoo penguin diet at the Falklands is limited to either broad taxonomic divisions of prey items or dietary samples collected only on a single day. This study is the first to investigate gentoo penguin diet at Cow Bay, Falklands, to the species level, over repeated sampling intervals during the breeding period. Through stomach content analysis, we determined diet over a large temporal scale (2002/2003/2004–2011/2012/2013) and between the guard and creche periods of chick rearing. The principle prey item by reconstituted mass was rock cod fish Patagonotothen spp., for all periods (47–78 %) except that of the 2012/2013 creche period (19 %) when Falkland herring Sprattus fugensis made up the bulk of the diet (52 %). Of the cephalopods recovered, Patagonian squid Doryteuthis gahi was prominent (1–24 %), while crustaceans contributed negligibly to gentoo penguin diet. Our findings revealed that gentoo penguins breeding at the Falkland Islands were primarily demersal foragers with an ability for pelagic feeding. Diet choice appears to reflect prey availability.

In birds, courtship is generally short relative to the whole breeding cycle. Emperor penguins (Aptenodytes forsteri), however, are an exception as their courtship period is much longer (ca. 6 weeks) than the courtship of other penguin species. This strategy may appear surprising, as it is especially costly to fast and endure drastic climatic conditions for long periods at the colony (1.5 and up to 4 months for females and males, respectively). We examined here the reasons of this extended courtship period and found that emperor penguins returned earlier to the colony when primary oceanic production before breeding was high. This suggests that emperor penguins return to the colony as soon as primary oceanic production in summer allows them to replenish their body reserves. The extended period of time spent at the colony during courtship may therefore result from an evolutionary process that confers advantages to emperor penguins that arrive earlier at the colony by reducing predation risks and offering better chances of securing a partner.

Feathers are used commonly for stable isotope analysis to assess the foraging ecology and migration patterns of birds. However, these studies often require knowledge of species-specific feather isotopic discrimination factors (the differences in isotopic ratios between a species’ diet and feathers), which can be influenced by a species’ physiological state during molt. In this study, we determined the isotopic discrimination factors (Δ13Cdiet−feather and Δ15Ndiet−feather) between adult gentoo penguin (Pygoscelis papua) diet and feathers in a controlled study. In addition, we tested whether molt duration or the magnitude of voluntary dietary reduction during molt influenced isotopic discrimination, as previous studies have found that nutritional stress can exaggerate 15N enrichment and in some cases lead to 13C depletion in feathers. Contrary to this hypothesis, we found no effect of molt duration or dietary reduction on discrimination factors, suggesting that isotopic discrimination is not linearly related to these measures of fasting intensity in penguins. Furthermore, we found that the range of Δ15Ndiet−feather found in several species of penguins, which fast while they molt, was similar to discrimination factors in fish-eating birds, which do not fast during molt. It is likely that species-specific metabolic adaptations that limit nutritional stress while fasting and variation in their relative reliance on endogenous vs. dietary pools during feather growth may confound the use of Δ15Ndiet−feather as a general measure of nutritional stress when comparing among species.

We report here the first published observations of killer whales (Orcinus orca) feeding on penguins in Antarctica. The sightings took place in the Gerlache Strait off the western Antarctic Peninsula during February 2010. Two species of pygoscelid penguins were taken—gentoo (Pygoscelis papua, at least four individuals) and chinstrap (P. antarctica, 2). From remains left at the surface, it was clear that the killer whales fed mainly on the breast muscles, although some penguins may have been swallowed whole. The killer whales were ecotype B, which are purported seal specialists, but we also saw ecotype A, prey specialists on Antarctic minke whales Balaenoptera bonaerensis, chase, but not catch penguins. Because of their small relative size, if penguins are regularly targeted by killer whales in Antarctica, the impact on their populations could be significant.

On 20 and 22 January 2007, we observed macaroni penguins (Eudyptes chrysolophus) on Avian Island, Antarctica, approximately 1° south of the Antarctic Circle along the Western Antarctic Peninsula (WAP) near Adelaide Island, a new high-latitude observational record for the species within this region of the continent. Additionally, we report several extra-limital sightings of macaroni penguins over the last decade at relatively lower latitudes along the WAP near Anvers Island, including observations of breeding attempts. Although vagrancy cannot be ruled out as a possible causal factor in our observations, we hypothesize that a climate-induced shift in the species’ bio-geographic range may be in progress. In this context, our observations are similar to the well-documented range shifts and eventual establishment of breeding populations by other sub-Antarctic penguin species along the WAP, over the last three decades, in response to regional climate warming. We highlight that the few observations reported here do not provide conclusive evidence for any putative causal mechanism explaining the presence of macaroni penguins at locations outside their natural geographic range. However, our observations are important for developing a better understanding of the natural history of the species along the WAP.

The study of scats of adult male Antarctic fur seals Arctocephalus gazella (AFS) revealed occasional frequent capture of penguins. Although AFS adult males have been occasionally reported to kill king penguins Aptenodytes patagonicus at the shore, here we report the first observations of at-sea predation by AFS on adult king penguins in the Crozet archipelago, southern Indian Ocean. During our 20 days survey, we observed 17 penguins attacked and either severely injured or killed and consumed. Only AFS adult males were seen catching king penguins successfully. Some adult females and sub-adults also attempted to catch penguins, either at sea or in land, and so did subantarctic fur seals Arctocephalus tropicalis individuals. Our results confirm the ability of fur seals to catch and predate large seabirds, even at sea.

Petermann Island (65°10′S, 64°10′W), one of the Antarctic Peninsula’s most frequently visited locations, is at the epicenter of a rapid shift in which an Adelie penguin dominated fauna is becoming gentoo penguin dominated. Over the course of five seasons, the breeding productivity of Adelie and gentoo penguins breeding at Petermann Island were monitored to identify drivers of this rapid community change. The impact of tourist visitation on breeding success was also investigated. Consistent with larger trends in this region, the Adelie penguin population decreased by 29% and the gentoo penguin population increased by 27% between the 2003/2004 and 2007/2008 seasons. Reproductive success among Adelie penguins ranged from 1.09 to 1.32 creched chicks/nest, which was higher than or comparable to other sites and is an unlikely explanation for the precipitous decline of Adelie penguins at Petermann Island. Whereas gentoo penguin reproductive success was lowest in colonies frequently visited by tourists, Adelie penguin colonies frequently visited by tourists had higher reproductive success than those visited only occasionally. These results are placed in the context of other studies on reproductive success and the impact of tourist visitation on breeding colonies of Adelie and gentoo penguins.

All crested penguins present a unique reversed hatching asynchrony: the larger second-laid egg (B-egg) hatches before the smaller first-laid egg (A-egg). Although both eggs often hatch, the A-chick generally dies of starvation within days after hatching. However, within rockhopper penguins, the population at the Falkland Islands is unique in that some birds manage to raise both chicks. Although it has been suggested that the egg size dimorphism between A- and B-eggs may explain how long both eggs and chicks survive, this hypothesis has never been explicitly tested. We expect that both eggs are retained longer in the less dimorphic clutches than in the more dimorphic ones. In this paper, we have compiled egg measurements for three rockhopper penguin species (Eudyptes chrysocome, E. filholi and E. moseleyi) in order to compare the intra-clutch egg size dimorphism among these species. Furthermore, we have collected new data to compare egg size dimorphism between two populations of E. chrysocome (Falkland Islands versus Staten Island). A-egg volumes are more variable between species and populations than B-egg volumes. E. chrysocome and especially the population from the Falkland Islands produces the largest A-eggs and the least dimorphic eggs. Nevertheless, as differences in A-egg volumes between species and between the populations of Falkland Islands and Staten Island are stronger and more significant than differences in egg dimorphism, we suggest that A-egg volume, more than egg dimorphism, could be one of the factors influencing the prevalence of twins. A large A-egg and/or reduced egg dimorphism is probably necessary to enable rockhopper penguins to raise two chicks, but other reasons may also be involved which enable them to keep both eggs and chicks. Fil: Demongin, Laurent. Max Planck Institute für Ornithologie; Alemania Fil: Poisbleau, Maud. Max Planck Institute für Ornithologie; Alemania Fil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Schiavini, Adrian Carlos Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Quillfeldt, Petra. Max Planck Institute für Ornithologie; Alemania Fil: Eens, Marcel. Universiteit Antwerp; Bélgica Fil: Strange, Ian J.. New Island Conservation Trust; Islas Malvinas

The gentoo penguin (Pygoscelis papua) is one of the most widespread penguin species and has been proven to be highly plastic in many aspects of its ecology. However, data from their sub-Antarctic range suggest an unexplained decline of their populations over the last 10–20 years, stressing the need for additional knowledge on their breeding ecology and demography. The present study provides insights into the breeding ecology of the gentoo penguin at a major breeding site, Kerguelen Archipelago, over three breeding seasons (1987, 2002 and 2003). Similarly to other northern populations, gentoo penguins breeding at Kerguelen exhibited winter laying, slow provisioning rate, slow growth rate associated with an extended rearing period and relatively low breeding success compared to southern populations. Our study also revealed interannual differences in the timing of laying and growth parameters as well as unusual sex differences in parental investment. Despite their high plasticity, there are indications that gentoo penguins at the northern edge of their range might work at the upper limit of their capacities. Sub-Antarctic populations would, therefore, be more sensitive to environmental changes than more southerly ones and need to be closely monitored.

As part of a monitoring study of Adélie and Gentoo penguin colonies, birds occupying nests with eggsand chicks in crèches were counted annually from the 1995/1996 to the 2006/2007 seasons at Stranger Point, Isla 25 de Mayo (King George Island), Antarctica. During the study period the Adélie penguin population showed a decrease of 62%. The number of chicks in crèches followed a similar trend, the smallest number occurring in 2002, when it was 63% lower than in 1995/1996. In contrast, the Gentoo breeding population size increased by 68%, while chicks produced increased by 63%. Despite the opposing trends in population size between species, there was a positive relation in their interannual variation, although the extent, and for some years the direction, of the change observed always favoured Gentoo penguins. Breeding success (chicks in cre`ches/nests with eggs) fluctuated between 0.65 and 1.26 for Ade´lies and between 0.76 and 1.27 for Gentoo penguins, and did not differ significantly between species. The similar breeding success of these species suggests that the contrasting population trends observed were driven by factors operating over winter. We suggest that current changes in environmental conditions may affect adult birds of both species during the previous winter with different intensity but in a roughly similar way, but that juvenile survival of both species and thus the recruitment of new breeders might be affected differentially, with a much lower survival rate of juvenile Adélie penguins. Fil: Carlini, Alejandro R.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Coria, Néstor Rubén. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Santos, Maria Mercedes. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Negrete, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Juares, Mariana Alejandra. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Daneri, Gustavo Adolfo. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina

The movement of marine vertebrates has been tracked using a variety of techniques, all of which depend on the external attachment of a transmitting or recording device. However, these devices can have negative effects on the subject animals, limiting both the quantity and quality of data collected. We present a new method for monitoring large-scale movement of marine vertebrates that uses behavioural data stored on a surgically implanted data logger. The technique (‘behavioural geolocation’) relies on the principles of light-based geolocation but rather than measuring ambient light levels, changes in diving behaviour associated with sunrise and sunset are used to infer daylength and time of local sunrise, and hence location. We present data from a trial, post-hoc, analysis of diving data collected from macaroni penguins Eudyptes chrysolophus during long foraging trips associated with incubation and preparation for moult. Our results showed that the penguins usually travelled to the polar frontal zone to the north of their breeding colony at South Georgia, an area broadly consistent with previously measured behaviour and the availability of preferred prey at this period of the annual cycle.

Animal-borne camera loggers were used to examine the patterns of prey encounter and feeding behaviour of gentoo penguins at King George Island, Antarctica. The still images from the camera loggers showed that the penguins encountered the swarms of krill for 25.5% (range: 8–38%) of their dives (>5 m) on average, during their foraging trips (mean duration of 5.4 h, n = 7 trips). They encountered krill swarms during the dives to 10–70 m depth, in pelagic as well as benthic habitats. In the benthic habitat, the penguins swam just above the sea floor and headed downward over a krill swarm, probably using the sea floor to assist them to feed on mobile swarms. The shallow coastal waters would be the important foraging habitat of gentoo penguins breeding in King George Island.

The short-term behavioural effects of helicopter overflights on breeding king penguins Aptenodytes patagonicus at South Georgia were examined. Seventeen helicopter overflights were made at altitudes between 230 and 1,768 m (750–5,800 ft) above ground level. Noise from the aircraft engines and helicopter blades increased sound levels in the colony from a background level of 65–69 dB(A) to a maximum mean peak level of 80 dB(A) during overflights. Penguin behaviour changed significantly during all overflights at all altitudes compared to the pre- and post-flight periods. Pre-overflight behaviour resumed within 15 min of the aircraft passing overhead and no chicks or eggs were observed to be taken by predators during overflights. Non-incubating birds showed an increased response with reduced overflight altitude, but this was not observed in incubating birds. Variability in overflight noise levels did not affect significantly the behaviour of incubating or non-incubating birds. Penguins exhibited a reduced response to overflights as the study progressed (despite later flights generally being flown at lower altitudes) suggesting some degree of habituation to aircraft. To minimise disturbance to king penguins we recommend a precautionary approach such that overflights are undertaken at the maximum altitude that is operationally practical, or preferably are avoided altogether.

The rockhopper penguins Eudyptes chrysocome have recently been split into the northern E. moseleyi and the southern E. chrysocome rockhopper penguin. It is therefore crucial to have a comprehensive understanding of the biology of each species in order to develop appropriate conservation measures. We investigated the breeding biology of the southern rockhopper on New Island, in the western part of the Falklands Islands, by following the breeding attempt of 160 pairs during the 2006/2007 season and examining the effect of lay time and colony habitat on breeding success. Specifically, we compared survival and growth parameters between A- and B-eggs and chicks from non-manipulated and artificially manipulated nests to investigate why southern rockhopper penguins in the Falkland Islands are more able to fledge an A-egg (first laid) than conspecifics elsewhere. Breeding was highly synchronous, with no significant difference in the breeding success between early and late breeders or between pairs breeding in different habitats. We demonstrate for the first time that the A-egg produced by the southern rockhopper penguin has, when alone, the same theoretical intrinsic potential to lead to a fledged chick as the B-egg. In contrast, the hatching success and survival of the B-chick was similar when alone or in a two-egg clutch.

Macaroni penguins have evolved to cope with the highly variable conditions of the Southern Ocean. However, changes in prey supply and patchiness potentially associated with changes in climate and krill fishing activity may be occurring too rapidly for the penguins to adapt. We use a stochastic dynamic programming model to examine how changes in both the mean and patchiness of krill supply may affect the foraging decisions, and therefore breeding success, of female macaroni penguins at South Georgia. We predict that rapid changes in the mean supply of prey will have more of an effect on the condition of the female and chick than changes in prey patchiness, and that changes in foraging behavior compensate for changes in prey up to a threshold point, beyond which breeding success is likely impacted. In particular, we predict that the location of the threshold is affected by whether or not the penguins are adapted to the prey environment in which they are foraging, with the female and chick receiving on average 20% less of their daily energetic requirement if the female is not foraging optimally.

International audience; We investigated whether delayed plumage maturation occurred in king penguins (Aptenodytes patagonicus). Therefore we examined the relationships between age and sex on spectral properties and size of two colored plumage patches and a UV-reXective beak spot, using known-age cohorts. Unlike the colored patch on the breast, we found age diVerences in ear and beak coloration. These results suggest that head ornaments in king penguins could signal sexual maturity or social status. No sex diVerences were found in the intensity of colored ornaments, which can result from mutual mate choice or genetic correlation between sexes. Size of colored patches did not relate to age or sex.

Photographs of gentoo and king penguins were taken in the field on a bright and sunny day first in colour (here reproduced in black and white) and then, seconds later, through a filter that transmits only UV radiation and blocks all visible light. Because of the lower light intensity and different focal point of UV, it is unavoidable that the UV photographs turn out less sharp and less well focused than photographs taken with visible light. Comparisons of the two sets of photographs show that king penguins with white (but not yellow or orange) auricular patches reflect UV from these areas. Furthermore, the beaks of juvenile gentoo penguins, but not those of the adults, are UV reflectant. The findings are discussed in view of recent suggestions that UV reflection in penguins could be part of a communication system. However, this paper argues that as long as UV perception in penguins has not been demonstrated, UV reflection in penguins ought to be seen as an “associative phenomenon” with no significance to penguin behaviour.

A new ground-based technique for estimating the density of nesting Adelie penguins (Pygoscelis adeliae) within occupied habitat is described and evaluated using an experimental approach with model penguins. In this set-up, an operator takes photos with a camera mounted on a 3-m pole at pre-determined sampling locations within habitat occupied by nesting penguins, and the actual boundaries of the plot in which penguin density is estimated are added post-survey. Density estimates are calculated by overlaying slope-specific templates delineating plot boundaries and distances of known dimensions onto the digital photos to allow a distance-sampling analysis to correct for any negative bias in counts arising from a proportion of penguins being obscured. Experimental assessment of biases in density estimates because of misclassification error was

The impact of penguins on vegetation cover is a frequently documented but not fully explained phenomenon, especially over geological time scales. To address this we collected two ornithogenic sediment cores from Ardley Island, Antarctica, and reconstructed historic variations of penguin population and different vegetations by using biomarkers fecal sterols and n-alkanols in the cores. The three major types of vegetations in the colony, namely coprophilic algae, moss and lichen, exhibited quite different trends, in concert with fluctuations in the penguin populations: a moderate penguin population is favorable for coprophilic algae and mosses, while lichen abundances decreased whenever penguin population increased, and vice versa. Cholestanol and alkanols biomarkers, in combination with bioelements, provided integrated information about the 2,400-year evolution of the penguin colony: historical penguins and vegetation populations, their fluctuations, and their interactions.

Emperor penguins (Aptenodytes forsteri) were studied at the Snow Hill breeding colony in November 2006 to determine the effect of people on penguins traveling between the colony and the sea to forage. We tested the null hypothesis that the presence and number of people had no effect on the trajectory of movement or the number and duration of pauses. The distances at which penguins noticed people (mean 35.6 m), changed direction (mean 22.8 m), and the number and duration of pauses increased significantly with increases in the number of tourists in their path, which explained more than 50% of the variance. Undisturbed penguins usually tobogganed on their ventral surface over the ice. When penguins noticed people, they usually stood up and often called. In 10 min observation periods, penguins traveling more than 200 m from people paused an average of

Heat shock proteins (HSPs) are synthesised under stressful conditions such as exposure to elevated temperatures, contamination, free radicals, UV light or pathophysiological states resulting from parasites and/or pathogens. HSPs function to protect cells by means of modulation of protein folding. In Antarctica, these proteins have been studied in such organisms as protozoa and fishes, without attention to geographical variation. We studied the variation of HSP70 and HSP60 levels in Gentoo, Adelie and Chinstrap penguins among different populations along the Antarctic Peninsula from King George Island (62°15′S) to Avian Island (67°46′S). Our results show that the northern population of Gentoo penguin showed higher levels of HSP70 and HSP60 than the southern population. High temperature, human impact and immunity as a proxy for parasites and diseases in northern locations could explain such variation. Adelie penguin only showed significant geographical variation in HSP70, increasing north to south, a pattern perhaps related to increased UV radiation and decreased temperatures from north to south. Chinstrap penguin shows no population differences in the variation in neither HSP70 nor HSP60, although HSP70 showed marginally significant differences. Sexual differences in the level of these proteins are also discussed.

Satellite telemetry was used to determine the winter movements of eight chinstrap penguins from two breeding colonies in the South Shetland Islands, Antarctica during the 2000 and 2004 austral winters. Chinstrap penguins foraged largely inshore, on the shelf, north of the South Shetland Islands during 2000, but foraged mainly offshore in pelagic waters in 2004. Analyses of foraging trip durations during the chick-rearing periods that preceded the 2000 and 2004 winters suggest that prey were more abundant inshore during the summer of 2000 than in 2004. Oceanographic data further revealed the presence of a strong shelf-slope front in 2000 that was absent in 2004. In addition, two of the six chinstrap penguins from the colony in Admiralty Bay migrated from the South Shetland Islands region to the vicinity of the South Orkney and South Sandwich Islands, distances of 800 and 1,300 km, respectively. We postulate that the differences in winter migratory behavior among chinstrap penguins from this colony may reflect individual ties to different ancestral epicenters of chinstrap populations; one older and local in the South Shetland Islands and one relatively recent, arising from the emigration of chinstrap penguins that occurred during the expansion of this species in the mid-1900s.

This work is a quantitative analysis of the population of breeding pairs of Pygoscelis adeliae and Pygoscelis antarctica, which use Penguin Island as a breeding area. There was a decrease in the populations of P. adeliae and P. antarctica by 75 and 66%, respectively, from the breeding season of 1979/1980 to 2003/2004. A mixed breeding colony of both species was also documented, according to published data which has existed since 1979/1980. The P. antarctica has an advantage over P. adeliae in this mixed breeding situation, where the breeding pairs of the former increased by 127%, indicating an interspecies competition for nesting ground.

We examined the incidence of extreme diving in a 3-year overwintering study of emperor penguins Aptenodytes forsteri in East Antarctica. We defined extreme dives as very deep (> 400 m) and/or very long (> 12 min). Of 137364 dives recorded by 93 penguins 264 dives reached depths > 400 m and 48 lasted > 12 min. Most (65%) very long dives occurred in winter (May–August) while 83% of the very deep dives took place in spring (September–November). The two most extreme dives (564 m depth, 21.8 min duration) were separate dives and were performed by different individual penguins. Penguins diving extremely deeply may have done so as part of their foraging strategy whereas penguins diving for very long times may have been forced to do so by changes in the sea-ice conditions.

International audience; The taxonomy of rockhopper penguins, Eudyptes chrysocome (Forster 1781), is contentious. Some authorities recognise three subspecies based on morphological differences and geographical separation of breeding populations while others suggest that morphological differences support classifying rockhopper penguins as two distinct species. The taxonomy of rockhopper penguins is of more than academic interest as breeding colonies worldwide have declined markedly in size since the 1930s and rockhopper penguins are currently listed as vulnerable by the IUCN. We compared the genetic distances between three mitochondrial gene regions from the three putative rockhopper penguin subspecies with the distances between various penguin sister species to clarify the taxonomy and systematics of rockhopper penguins. Genetic distances between the rockhopper penguin taxa, relative to other closely related penguin species, support reclassifying the three rockhopper penguin subspecies as species. Reclassification of rockhopper penguins as three species could result in their conservation status being upgraded from vulnerable to endangered.

The use of automated systems to record the identity of individual penguins and their movements in and out of a colony can provide an effective means of studying penguin biology remotely. A new gateway installed at the macaroni penguin colony at Fairy Point (513 breeding pairs in 2003) on Bird Island, South Georgia in February 2003 and the implantation of passive integrated transponders for identifying individuals is described. The reliability of the system in recording penguin arrival and departure during the end of the 2002/2003 breeding season and over the complete 2003/2004 breeding season was tested using an independent method of radio telemetry. Results from two seasons of trials indicated that there was only a 3.7% probability of the gateway missing a penguin in 2002/2003 (185 total logged crossings) and 3.9% in 2003/2004 (1,309 total logged crossings); this compared with probabilities of 16.2 and 7.9% using radio telemetry, both differences being highly significant. This automatic logging gateway is therefore shown to be a more reliable means of recording the transit of penguins between the colony and sea and, over the longer term, elucidating colony attendance and survival rates of this species at South Georgia.

Rockhopper penguins (Eudyptes chrysocome) breeding on Staten Island, Argentina, were satellite tracked in 2002 and 2003 during the onset of their winter migration. After their moult, the dispersal of 24 birds was monitored for a mean period of 50.0±40.3 days. Birds travelled at a mean velocity of 3.1±1.1 km/h. The mean minimum distance travelled was 1,640±1,425 km; the maximum distance to the colony was generally less than 1,000 km, although one bird travelled more than 2,000 km from the colony. The penguins dispersed over an area totalling about 1.3 million km², ranging from 50 to 62°S and from 49°W in the Atlantic to 92°W in the Pacific, and covering polar, sub-polar and temperate waters in oceanic regions as well as shelf waters. Despite the very wide dispersal, both temporally and spatially, two important wintering grounds for rockhopper penguins from Staten Island could be identified, both located over shelf regions: one extended from Staten Island to the north along the coast of Tierra del Fuego up to the Magellan Strait; the other was located over the Burdwood Bank, an isolated extension of the Patagonian Shelf to the south of the Falkland Islands. The Drake Passage also appeared to be an important area for wintering penguins, although dispersal was far more widely spread. Comparison with data obtained during winter from rockhopper penguins originating from the Falkland Islands showed that the area off the coast of Tierra del Fuego was used more or less exclusively by birds from Staten Island, whereas the Burdwood Bank was shared with penguins coming from southern colonies in the Falkland Islands. The implications of these findings are discussed with regard to (a) opposing population trends of rockhopper penguins in the Southwest Atlantic, and (b) the urgent need to establish adequate conservation measures for species and habitat protection.

A key factor influencing wildlife responses to human activity is the degree to which animals have been previously exposed to human stimuli. On subantarctic Macquarie Island, gentoo penguins Pygoscelis papua breed in areas of high and low human activity (on and off-station, respectively). We investigated the behaviour and breeding success of gentoo penguins on and off-station, by a) comparing the behavioural responses of guarding gentoos before, during and after exposure to standardised pedestrian approaches, and b) employing an observational study to determine how human activity may have contributed to within-season breeding success in light of other environmental and site variables. Behavioural responses to pedestrian visitation by gentoos off-station were significantly stronger than those of birds breeding on-station. However, no relationship was found between pedestrian activity and breeding success off-station. Breeding success was, however, positively related to colony size, and negatively related to the activity of other penguins, the number of nearby southern elephant seal Mirounga leonina harems and the location of colonies within short grassland. On-station, breeding success was amongst the highest recorded for that season. Habituation, predator exclusion and the relevance of these findings for management are discussed.

Inter-annual variability in the diet of Chinstrap penguins (Pygoscelis antarctica) at Laurie Island, South Orkney Islands was examined based on stomach contents of adults coming ashore during the 1997/1998–2001/2002 breeding seasons. Krill (Euphausia superba) dominated the diet either as frequency of occurrence (in 100% of samples), number (>99%), and percentage contribution in weight (>99.5%). Other prey items were minor but did vary between years. The contribution in weight of fish, amphipods and cephalopods ranged between 0.01–0.5

The foraging strategies of king penguins from Heard and Macquarie islands were compared using satellite telemetry, time-depth recorders and diet samples. Trip durations were 16.8±3.6 days and 14.8±4.1 days at Macquarie and Heard islands, respectively. At Macquarie Island, total distances travelled were 1281±203 km compared to 1425±516 km at Heard Island. The total time the penguins spent at sea was 393±66 h at Macquarie Island and 369±108 h at Heard Island. The penguins from Macquarie Island performed more deep dives than those from Heard Island. King penguins from Macquarie Island travelled 1.5±0.2 km h−1 day−1 compared to 1.3±0.1 km h−1 day−1. At Macquarie Island, 19% of dives were upto 70–90 m depth compared to 35% at Heard Island. The main dietary prey species were the fish Krefftychthis anderssoni and the squid Moroteuthis ingens in both groups. The differences in the at-sea distribution and the foraging behaviour of the two groups of penguins were possibly related to differences in oceanography and bathymetric conditions around the two islands. Dietary differences may be due to interannual variability in prey availability since the two colonies were studied during incubation but in different years.

Human disturbance can be considered to have similar effects as predation risk for animals. Thus, when disturbed, animal responses are likely to follow the same economic principles used by prey when encountering predators. We simulated predator attacks with different characteristics and in different situations to study the factors that determine the escape response of 1-year-old chinstrap penguins. The results indicate that 1-year-old penguins adjusted their escape behaviour according to the level of risk posed by the researcher acting as a potential predator. When 1-year-old penguins were close to a breeding subcolony, they started to escape later, and fled shorter distances, at lower speeds, and not fleeing directly into the subcolony. This contrasts with their fleeing behaviour far from subcolonies, when penguins fled sooner, for longer, and faster, and in a direction that maximized the distance between themselves and the experimenter, by fleeing directly away from the experimenter. This might suggest the existence of a trade-off between fleeing from the predator and avoiding entering the subcolony where 1-year-old penguins will receive aggressive responses from breeding adults. The type of approach was not important in deciding when to flee. However, penguins did escape for longer distances and faster when approached directly, showing that penguins were able to assess risk level based on predator behaviour. Our findings may have implications for management of penguin colonies visited by tourists. The delimitation of buffer areas and advice on how tourists should behave when approaching penguins might arise from studies of the factors that affect risk assessment of penguins.

The Adelie penguin, Pygoscelis adeliae, an important component of the Antarctic marine ecosystem, is closely associated with sea ice. Using data collected by Japanese Antarctic Research Expeditions since the 1960s, we examined trends in breeding populations of this species around Lutzow-Holm Bay. Ten colonies ranging in size from 10 to 2,500 individuals were counted along the Soya Coast. Populations fluctuated synchronously, and overall increased at most colonies, except for two: one located deep inside the bay and another where human disturbance was substantial. Populations tended to increase during, or after, periods of sparse sea ice in summer, a condition that occurred once every decade. An increase in population size also occurred 5 years after a winter of extensive sea ice and after a winter of especially reduced sea ice.

We examined the biological characteristics of euphausiids found in the stomachs of Adelie penguins in relation to sea-ice conditions in Lutzow-Holm Bay over three seasons. Euphausiids, especially Euphausia superba, proved to be a staple food for Adelie penguins irrespective of the ice condition. Body length and maturity-stage compositions of euphausiids were different among seasons, probably reflecting sea-ice condition in summer. The mean body length decreased and maturity regressed during each season in E. superba, which was partly attributable to the selective feeding on large, mature female krill by Adelie penguins. The 1995/1996 year class of E. superba, which was spawned when the sea ice was most developed, was strong and conspicuous in the 1996/1997 and 1997/1998 seasons. This vigor indicates that sea ice provided females with good spawning conditions and larvae with good growth and survival rates.

Although the majority of chinstrap penguins (Pygoscelis antarctica) inhabit the Scotia Arc, a minus- cule population of ten breeding pairs has been reported several times from Chinstrap Islet, in the Balleny Islands, 5,000 km distant on the opposite side of Antarctica. An aerial photographic census (December 2000) reveals that the overall penguin population of the Balleny Islands has declined by 8% since the last census 16 years ago, while the combined populations of the two largest colonies, Chinstrap Islet and Sabrina Islet, have increased by 11%. A ground visit confirmed for the first time that chinstrap penguins also breed on Sabrina Islet, occupying 20-24 nests on the margins of the Adelie colony (3,790 pairs in all). The small size and anomalous location of the Balleny Islands chinstrap population clearly warrant further study and the strongest protective measures.

Data on foraging trip durations and meal sizes were collected by means of an automated monitoring system from breeding Adelie penguins (Pygoscelis adeliae) at Bechervaise Island over eight breeding seasons, commencing in 1991–92. Significant interannual differences in duration of foraging trips, meal sizes and diet composition were observed. These parameters were correlated with breeding success and fledging masses, and provide useful indicators of food availability during the breeding season. Chicks were particularly vulnerable to a decreased availability of food during the first 3 weeks after hatching.