Adelie Penguins Pygoscelis Adeliae Research Articles

Assessing <i>Serratia</i> spp. pathogenic potential from cryogenic habitats

The genus Serratia are opportunistic bacteria widely spread in natural environment. At the same time, this bacterial genus consists of the species associated with outbreaks of nosocomial infections. Serratia species are found in extreme habitats, but pathogenic potential of polyextremophilic strains in this genus remains unexplored. The aim of this study was to compare the genomes of two Serratia strains isolated in polar regions, primarily examining genetic factors of virulence and adaptation to cryogenic environment. During the 56th Russian Antarctic Expedition the Serratia liquefaciens 72 strain was isolated from a guano sample of the Adelie Penguin (Pygoscelis adeliae) colony on Tokarev Island (Haswell Archipelago, East Antarctica). The Serratia fonticola 5l strain was isolated from the frozen carcass of moose (Alces alces) fossils found on the Buor-Khaya Peninsula near the Laptev Sea coast (Yakutia Region, Russia). The whole-genome sequencing of such strains allowed to reveal genetic structures evidencing about their successful adaptation to low temperatures. Thus, it was found that both genomes contain genes encoding the main cold shock proteins, phylogenetically close to the corresponding genes in the hypobarotolerant Serratia liquefaciens strain ATCC 27592. Furthermore, both strains bear a cluster of tc-fABCD genes determining the bacterial adhesion to epithelial tissues, and the genes for RTX toxins — adhesins, crucial factors of biofilm formation in pathogenic Gram-negative bacteria. Experimental studies confirmed the ability of Serratia liquefaciens 72 and Serratia fonticola 5l to actively form biofilms in a wide temperature range (from 6°C to 37°C). The results obtained indicate that the examined genus Serratia strains isolated in Arctica and Antarctica exert overall similar adaptation strategies to polar climate, including the ability to produce pili, show active adhesion, and biofilm formation under low temperatures. Genetic adaptive factors may also act as pathogenicity factors allowing extremotolerant Serratia strains to exert traits of opportunistic and nosocomial pathogens and spread via chilled food-borne transmission. The wide use of food technologies, such as cooling and vacuum sealing, can potentially create a new ecological niche favourable for selection of psychrotolerant and hypobarotolerant pathogens. The data obtained allow to raise a question about necessity of further studies to monitor genetic diversity among psychrophilic hypobarotolerant microbial populations possessing pathogenic and epidemic potential.

Homing Ability of Adélie Penguins Investigated with Displacement Experiments and Bio-Logging

Adelie Penguins Pygoscelis adeliae live exclusively in Antarctica and commute between the sea for foraging and the land for breeding. During these movements, they must navigate various environments: underwater, on sea ice and on land; an unusual set of challenges among animals. Navigation mechanisms of this species were intensively studied about 50 years ago, but technological limitation at that time made it hard to fully understand movement patterns under experimental as well as natural conditions. Recent developments in animal-borne data loggers have enabled us to record movement paths and activities of such birds. In this paper, we report the results of displacement experiments combined with bio-logging on Adelie Penguins, conducted for the first time since initial experiments more than 50 years ago. Two chick rearing birds were caught at their nests and data loggers with GPS and accelerometers were deployed on their backs. The birds were artificially displaced and released approximately 1 km from the breeding colony. From the release point, their options to return to the nest were either walking over land or swimming in the sea. The birds successfully returned to the colony 6.0 h and 8.1 h after release, taking 44 min and 41 min, respectively, from the onset of homeward movement. Both individuals took what appeared to be the straightest and shortest course crossing over land. They spent most of the homing phase (51.2% and 66.2%) walking and only entered the water – in the same place – in the last stretch homewards. The results of our study demonstrate the homing ability of Adelie Penguins from a distant location after artificial displacement and the potential use of positional and acceleration data to study the navigation of penguins that travel by both land and sea.

Habitat preferences of Adélie Pygoscelis adeliae and Chinstrap Penguins Pygoscelis antarctica during pre-moult in the Weddell Sea (Southern Ocean)

In order to understand and mitigate for the potential impacts of anthropogenic disturbance on marine predators, it is fundamental to gain insight into the drivers behind the temporal variation in their current distribution. With this in mind, we used platform terminal transmitter devices to track Adelie Pygoscelis adeliae and Chinstrap Penguins Pygoscelis antarctica breeding on the South Orkney Islands during the pre-moult phase of their annual cycles. We show that Adelie Penguins have an affinity to forage near and moult on sea-ice, and that Chinstraps remain over the shallower shelf waters during pre-moult, and return to the colony to moult. However, habitat models developed to predict the preferred foraging habitats of penguins during pre-moult had low predictive power. This indicates that predictive models may be insufficient to understand the distribution and foraging behaviour of penguins during certain stages of the life-cycle, and that collecting empirical data from individual colonies or archipelagos is vital if we are to understand the potential implications of future climate warming, or indeed the overlap with potentially competing fisheries.

A brown Adélie Penguin Pygoscelis adeliae breeding at King George Island, Maritime Antarctica

Plumage aberrations are rare in penguin species. Tracking their occurrence is helpful to understand the effects of these phenotypes on the life history of penguins, especially on mating, breeding, and foraging success. We registered a brown Adelie Penguin Pygoscelis adeliae at Turret Point, King George Island, Maritime Antarctica, during the middle of the 2017/2018 breeding season. The individual was brooding one chick in a nest located in the center of the colony and its partner was by its side. Both chick and partner showed normal plumage, reaffirming the recessive character of brown mutations. A breeding aberrant bird nesting in the center of the colony indicates that the brown coloration does not seem to affect mate selection, but we could not verify if it affects breeding success. This is the third published record for Adelie Penguins following a gap of 40 years. We stress, however, that possible misclassifications of brown aberrations in literature might be causing an underestimation of its occurrence rate in bird populations.

Diet of Adélie penguins (Pygoscelis adeliae) at Stranger Point (25 de Mayo/King George Island, Antarctica) over a 13-year period (2003–2015)

Fil: Juares, Mariana Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Direccion Nacional del Antartico. Instituto Antartico Argentino; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina

Seabird hotspots on icebergs in the Amundsen Sea, Antarctica

Our long-term study on the quantitative at-sea distribution of the upper trophic levels—seabirds and marine mammals—in polar ecosystems aims at quantifying the factors influencing their distribution as well as detecting possible spatial and temporal evolutions, with special attention to hydrography and to global climate changes. During the PS75 (ANT-XXVI/3) expedition of icebreaking RV Polarstern in February–March 2010, 6660 seabirds belonging to 11 identified species were recorded in the Amundsen Sea Embayment and Pine Island Bay during 760 half-hour transect counts. The most numerous species were by far Antarctic petrel Thalassoica antarctica, Adelie penguin Pygoscelis adeliae and snow petrel Pagodroma nivea representing together more than 80% of the total for the whole expedition (n = 5475). Substantial seabird hotspots were concentrated on three icebergs, representing 44% of all observations: 85% of the Antarctic petrels and 40% of the snow petrels. Moreover, 35 Cape petrels Daption capense capense were noted in the immediate surrounding of another iceberg (33% of the total). The highest overall counts were tallied on two icebergs: 250 Antarctic petrels and 500 snow petrels on the first one, and 1000 Antarctic petrels on the second. These hotspots seem to be typical for autumn situations and thus probably reflect the existence of pre-migratory gatherings following the breeding season. The consequences of these high local concentrations and thus the heterogeneity and non-normal distribution of the data are discussed, calculating mean values, standard deviation and density have very questionable value.

On the significance of Antarctic jellyfish as food for Adélie penguins, as revealed by video loggers

Concern of pelagic gelatinous organisms taking over perturbed marine ecosystems has led to a recent increase in research into this group. However, the significance of this group as prey remains challenging to assess, and hence, gelatinous consumers are often depicted incorrectly as dead ends of pelagic food webs. In the Southern Ocean, where a shift in trophic webs may favour gelatinous animals, we video-monitored prey intake of a key predator. Twenty-eight chick-rearing Adelie penguins Pygoscelis adeliae from Dumont d’Urville station (66°40′S, 140°01′E) were instrumented with miniaturized video loggers in 2014–2015. Among other items (krill, fish), 101 gelatinous organisms (n = 79 jellyfish, 6 salps and 16 unidentified) were observed on 13 of 21 exploitable video footages (total: 59 h). Importantly, 65.3 % of gelatinous organisms were attacked, but among them salps were not attacked. Attacks on jellyfish were significantly associated with the visible presence of the jellyfish’s gonad. Jellyfish were encountered at an average depth of 26.2 ± 10.4 m, significantly shallower than krill. Attacks occurred mostly during bottom, but also descent or ascent dive phases. Concomitant GPS location for four birds revealed that attacks on jellyfish occurred above the shelf, 35 km north from the colony, where sea ice concentration reached 88 %. These results indicate that Adelie penguins occasionally feed on jellyfish, even though other prey types are also available. Refining our perception of scyphozoans’ niche may thus help anticipate the functional response of the food webs to the extensive changes witnessed in the Antarctic environment.

Hydrodynamic handicaps and organizational complexity in the foraging behavior of two free-ranging penguin species

Animal movement exhibits self-similarity across a range of both spatial and temporal scales reminiscent of statistical fractals. Stressors are known to induce changes in these statistical patterns of behavior, although the direction and interpretation of such changes are not always clear. We examined whether the imposition of known hydrodynamic disruptors, bio-logging devices and flipper bands, induces changes in the temporal organization (complexity) of foraging sequences in two penguin species, little penguins (Eudyptula minor) and Adelie penguins (Pygoscelis adeliae). Detrended fluctuation analysis showed that foraging sequences produced by little penguins carrying larger loggers were more complex, i.e., were more erratic tending toward greater stochasticity, than those carrying smaller loggers. However, logger size did not affect complexity in foraging sequences of Adelie penguins. Logger position was associated only weakly with altered complexity in little penguins, with individuals carrying loggers in the middle of their backs displaying slightly more complex dive sequences than those carrying loggers lower on their backs. Finally, despite their known negative effects on penguin fitness, flipper bands were not associated with dive sequence complexity in little penguins. Despite that externally attached devices can disrupt certain behavioral parameters in diving seabirds, we found mixed evidence in support of the hypothesis that such devices significantly disrupt the time-structured organizational properties of foraging sequences in the two penguin species investigated. However, smaller species carrying larger loggers, and perhaps those positioned higher on their backs, may experience an added element of noise in their behavioral sequences that may indicate a departure from foraging behavior observed under normal, unburdened conditions.

Seabird colony effects on soil properties and vegetation zonation patterns on King George Island, Maritime Antarctic

Seabirds are among the most important vectors transferring biogenic compounds from the sea onto land in the polar regions and, consequently, influencing the properties of soil and vegetation. We studied the influence of bird colonies (Adelie penguin Pygoscelis adeliae, gentoo penguin P. papua and giant petrels Macronectes giganteus) on soil properties and plant communities on King George Island, Maritime Antarctic. We designated seven transects, each starting from the colony edge and running to a natural boundary feature, which were divided into contiguous sample plots where we identified specific plant taxa (Prasiola crispa, Deschampsia antarctica, Colobanthus quitensis, Usnea sp.), as well as hydrophilous and xerophilous ecological groups of mosses. Based on percentage contributions of each of these taxa, we distinguished six distinct vegetation zones along the transects, in which we measured physical (moisture, conductivity and pH) and chemical (NO3 −, NO2 −, NH4 +, K+ and PO4 3− content) soil parameters. Our study confirmed that, with increasing distance from bird colonies, the concentration of nutrients and soil conductivity decreased, while pH increased. The vegetation zones were clearly related to this gradient of seabird colony influence and occurred in the same sequence for all three bird species examined, although the largest colony of Adelie penguins had the strongest effect on vegetation. Similarly, the physical and chemical soil properties did not differ significantly between the colonies.

Demographic History of the Gentoo Penguin (Pygoscelis papua) and the Adélie Penguin (Pygoscelis adeliae) on Admiralty Bay, King George Island, Antarctica

Abstract. There is growing evidence that during the past 100 years the climate of the Antarctic Peninsula has changed from a relatively cold environment to an increasingly warmer one. The penguins that breed in the region are sensitive to oceanographic environmental and climatic conditions. They are considered the bellwether sentinels of the ocean because of their sensitivity to environmental changes. The present study aimed to determine the evolutionary history of the Gentoo Penguin (Pygoscelis papua) and Adelie Penguin (Pygoscelis adeliae) at Admiralty Bay, King George Island. A population genetics approach was used to examine the genetic variability of the two penguin species, searching to infer their demographics histories. The D-loop region from the mitochondrial DNA was sequenced in Adelie (n = 53) and Gentoo (n = 29) penguins. These species showed high genetic diversity, reflecting a large ancestral population size. The results also revealed that the Gentoo Penguin has had a stable population over ...

Assessing penguin colony size and distribution using digital mapping and satellite remote sensing

Changes in penguin abundance and distribution can be used to understand the response of species to climate change and fisheries pressures, and as a gauge of ecosystem health. Traditionally, population estimates have involved direct counts, but remote sensing and digital mapping methodologies can provide us with alternative techniques for assessing the size and distribution of penguin populations. Here, we demonstrate the use of a field-based digital mapping system (DMS), combining a handheld geographic information system with integrated geographical positioning system as a method for: (a) assessing penguin colony area and (b) ground-truthing colony area as derived from satellite imagery. Work took place at Signy Island, South Orkneys, where colonies of the three congeneric pygoscelid penguins: Adelie Pygoscelis adeliae, chinstrap P. antarctica and gentoo P. papua were surveyed. Colony areas were derived by mapping colony boundaries using the DMS with visual counts of the number of nesting birds made concurrently. Area was found to be a good predictor for number of nests for all three species of penguin. Using a maximum likelihood multivariate classification of remotely sensed satellite imagery (QuickBird2, 18 January 2010; Digital Globe ID: 01001000B90AD00), we were able to identify penguin colonies from the spectral signature of guano and differentiate between colonies of Adelie and chinstrap penguins. The area classified (all species combined) from satellite imagery versus area from DMS data was closely related (R 2 = 0.88). Combining these techniques gives a simple and transferrable methodology for examining penguin distribution and abundance at local and regional scales.

Paleodietary changes by penguins and seals in association with Antarctic climate and sea ice extent

Positioned near the top of the food web, the dietary composition of Antarctic penguins and seals can be an excellent indicator of the regional food web and thus the status of the marine ecosystem. The dietary composition of modern penguins and seals has been well investigated; a long-term time series of data on penguin and seal diets, however, are rare. Such data, especially any predating the initiation of human harvesting of fish, whales and seals in Antarctica, are crucial for understanding and predicting responses of regional marine food webs to natural climate changes. Here we review recent progress on research of paleodietary change in Antarctic penguins and seals, specifically the Adelie penguin (Pygoscelis adeliae) and Antarctic fur seal (Arctocephalus gazella). These studies indicate that the dietary changes of penguins correspond quite well with fluctuations in climate and sea ice extent during the Holocene. The depleted δ 15N ratios found in modern Adelie penguins support the “krill surplus hypothesis” in relation to historic human depletion of krill-eating fish, seals and whales.

Differential effects of increased corticosterone on behavior at the nest and reproductive output of chick-rearing Adélie penguins

Glucocorticoid hormones (GCs) are important mediators of physiological and behavioral responses to stress. While many studies have evaluated the environmental, behavioral, or physiological correlates of GCs and their effects on reproductive performances, further work is needed to clarify the relationship between GCs and fitness. Assessing the effects of increased GC levels on specific behaviors of breeding animals should improve our understanding of how GCs affect parental care. In this experimental study, we measured the effects of an experimental increase in corticosterone (CORT, the main avian GC) levels on the behavior of free-living male Adelie penguins (Pygoscelis adeliae) within the colony, their reproductive output, and the indirect consequences of both on the behavior of their partners. We show that increased CORT levels in males decreased their foraging time at sea while increased their attendance at the nest, although their attentiveness toward the nest itself decreased. In addition, treated males spent more time on comfort behaviors (e.g., preening), vocalizing, and engaging in positive social interactions relative to controls. Treatment further affected the behavior of their partners, but not chick begging and feeding rates. Penguins with increased CORT levels also exhibited decreased reproductive output. Previous studies of Adelie penguins in different life history stages and environmental conditions suggest that the consequences of CORT treatment on reproductive performance are context-dependent. In addition to the potential delay in the effects of increased CORT levels on reproduction, this context dependence should be taken into account when studying the behavior of free-living animals in relation to stress-inducing situations.

Flexible reproductive timing can buffer reproductive success of Pygoscelis spp. penguins in the Antarctic Peninsula region

ABSTRACT: Varying the timing of reproduction in response to local environmental conditions is akey factor influencing reproductive success. We used 19 yr (1991 to 2009) of data on breedingchronology and reproductive success of Adelie penguins Pygoscelis adeliae and gentoo penguins P. papua at King George Island, Antarctica to compare clutch initiation dates (CIDs), hatch rates,and creche rates at population and individual levels. The CIDs of both species occurred earlierwith warmer October temperatures, but gentoo penguins adjusted CIDs twice as much per °C oftemperature as Adelie penguins. Gentoo penguins also exhibited lower variances in hatch andcreche rates than Adelie penguins, suggesting that greater ability to respond to ambient condi-tions can buffer reproductive success. Mixed-effects models revealed that individual- and year-specific random effects on the overall population mean best accounted for observed variation inCIDs, with some individuals routinely breeding earlier than others. However, individual differ-ences in the relative timing of breeding provided no advantage for long-term reproductive suc-cess. The results suggest that, among gentoo and Adelie penguins, plasticity in CIDs with respectto environmental conditions is primarily a population-level rather than an individual-levelresponse. Energetic constraints of contrasting migratory and fasting behaviors likely contribute tothe different abilities to respond to warming spring temperatures. Overall, larger responses ofgentoo penguin CIDs to October temperature and lower variability in reproductive success,despite reduced reproductive success with delayed breeding, suggests that gentoo penguins arebetter equipped than Adelie penguins to adjust to rapid warming in the Antarctic Peninsulaecosystem.KEY WORDS: Phenology · Adelie · Gentoo · Climate change · Migrant

Non-consumptive factors affecting foraging patterns in Antarctic penguins: a review and synthesis

Recent research has clearly shown that the fear of predation, i.e. aversion to taking risks, among meso- predators or grazers, and not merely flight from an apex predator to avoid predation, is an important aspect of ecosystem structuring. In only a few, though well-docu- mented cases, however, has this been considered in the marine environment. Herein, we review studies that have quantified behavioral responses of Adelie penguins Pygoscelis adeliae and emperor penguins Aptenodytes forsteri to the direct presence of predators, and question why the penguins avoid entering or exiting the water at night. We also show, through literature review and new analyses of Adelie penguin diving data, that Antarctic penguins are capable of successful prey capture in the dark (defined here as \3.4 lux). Finally, we summarize exten- sive data on seasonal migration relative to darkness and prey availability. On the basis of our findings, we propose that penguins' avoidance of foraging at night is due to fear of predation, and not to an inability to operate effectively in darkness. We further propose that, at polar latitudes where darkness is more a seasonal than a year-round, daily fea- ture, this ''risk aversion'' affects migratory movements in both species, consistent with the ''trade-off'' hypothesis seen in other marine vertebrates weighing foraging success against predation risk in their choice of foraging habitat. Such non-consumptive, behavioral aspects of species interactions have yet to be considered as important in Southern Ocean food webs, but may help to explain enig- matic movement patterns and choice of foraging grounds in these penguin species.

Does Corticosterone Affect Diving Behaviour of Male Adélie Penguins? A Preliminary Experimental Study

Abstract The amount of energy that organisms can allocate to self-maintenance and/ or reproduction largely depends on their foraging strategies. Because of corticosterone (CORT) involvement in the control of energy metabolism, food intake and locomotor activity, recent studies have sought to demonstrate the role of this hormone in foraging decisions and performance. Moreover, considerable recent advances in animalattached loggers now allow the study of behaviour in free-living animals. In order to assess the effects of CORT administration on the foraging behaviour of free-living Adelie Penguins Pygoscelis adeliae, we studied a group with CORT implants and a control group without CORT implants, by attaching time-depth recorders to the two groups and monitoring them throughout up to seven consecutive foraging trips during the guard stage (in Adelie Land, Antarctica). We found that foraging trips duration was similar between both groups. Dive durations, time spent at the bottom phase of dives, and the number...

Stable isotopes reveal regional heterogeneity in the pre-breeding distribution and diets of sympatrically breeding Pygoscelis spp. penguins

While the foraging ecology of the Adelie penguin Pygoscelis adeliae and gentoo pen- guin P. papua has been well studied, little is known on the distribution and diet of these species out- side the breeding season. In the present study we used stable carbon (δ 13 C) and nitrogen (δ 15 N) iso- tope analyses of eggshells to examine the pre-breeding diets and foraging habitats of female Adelie and gentoo penguins from 23 breeding colonies along the eastern and western Antarctic Peninsula (AP), South Shetland Islands, and South Orkney Islands, in 2006. Adelie penguin eggshells from the eastern AP, South Shetland Islands, and South Orkney Islands shared similar isotopic signatures and were significantly lower in both δ 13 C and δ 15 N values than eggshells from birds breeding along the western AP. This result suggests that Adelie penguin populations that are geographically separated during the breeding season by the Adelie 'gap,' a 400 km region in the western AP devoid of breed- ing Adelie penguins, also inhabit geographically distinct habitats during the late winter prior to the breeding season. To a lesser degree, gentoo penguin eggshell isotope values also varied across breeding colonies, which likely reflects local scale variation in their near-shore foraging grounds. Furthermore, unlike the breeding period when krill (primarily Euphausia superba) dominates pen- guin diets in these regions, our findings suggest that fish and/or other high trophic-level prey species comprise a significant portion (46.8 to 62.9%) of female Adelie and gentoo penguin diets prior to breeding.

Individual Variation of Foraging Behavior and Food Provisioning in Adélie Penguins (Pygoscelis adeliae) in a Fast-Sea-Ice Area

ABSTRACT. To understand the effects of foraging behavior on the amount of food provided to chicks (meal mass and frequency), we monitored nest attendance and diving behavior of 20 Adelie Penguin (Pygoscelis adeliae) pairs that were rearing chicks. Because ice forms on the sea surface at night, parents foraged through cracks or within leads in the sea ice mainly during 0800–2400 hours. Birds that departed the colony in the afternoon and returned in the evening of the same day fed their chicks more frequently than those that made longer trips (i.e., those that departed in the afternoon and returned the next day or departed in the early morning and returned that evening). When the duration of the longest dive bout during each trip was longer, parents brought back heavier meals that contained larger krill. On average, birds made longer dive bouts when diving to greater depths. Thus, daily foraging pattern and foraging depth affected the provisioning rate, but the proportion of time spent foraging during the p...

Foraging strategies of Adélie penguins: adjusting body condition to cope with environmental variability

Animals modulate breeding effort by balancing investment in self-maintenance against investment in their young, potentially impacting reproductive success when faced with difficult con- ditions. This life history trade-off model has been evaluated for flying birds, especially those that for- age over large pelagic regions of relatively sparse prey availability. We evaluated its applicability to penguins which, lacking flight, depend on reliably available prey relatively close to colonies. We used transponders and an automated weighing system to monitor 40 to 75 breeding Adelie penguins Pygoscelis adeliae per season for 10 seasons, while environmental conditions varied dramatically, measuring foraging trip duration, parental mass change, and total food load delivered to chicks. Par- ents that lost the most mass during breeding provided more food to chicks while maintaining their own condition. In contrast, in years when adult mass was lower to begin with, parents recovered their own condition and delivered less food to chicks. Food loads were also related to environmental vari- ables, with parents making longer trips and delivering less food when access to prey was more diffi- cult, but delivering more food to 2-chick broods than to 1-chick broods. Penguins did not alternate between short (chick provisioning) and long (self-maintenance) trips, as has been observed in far- ranging seabirds. Nevertheless, our results indicate they regulated their condition depending on environmental and physiological factors, with impacts on the amount of food delivered to young and pre-fledging mass. Parental choice of multiple foraging habitats and depletion of prey in the nearest habitat due to intraspecific competition have important implications in explaining contrasting pat- terns observed among studies investigating the life history trade-off model in birds.

Using logistic regression models to predict breeding success in male Adélie penguins (Pygoscelis adeliae)

Measures of breeding success are traditionally derived using the proportion of total nests that successfully reach strategic stages across a breeding season, such as pair formation, egg laying or fledging chicks. The use of logistic regression has recently become a popular tool in avian literature for identifying influential factors that predict nest and/or individual breeding success. In this study, we use logistic regression models to assess the importance of a range of factors affecting male Adelie penguin (Pygoscelis adeliae) breeding success during the 2002–2003 austral summer, when the presence of icebergs and extensive sea-ice meant overall breeding success of Adelie penguins was low (16/51 focal males had chicks reach fledging point). Logistic regression models for the early breeding season showed that good/average nest quality and central/middle nest location within the sub-colony were the best predictors of successful pair formation. Later, during incubation, the most successful males were those that not only returned earlier but were also heavier upon arrival and built nests of at least average quality. During the final stage when chicks had begun to fledge, the combined parameters of heavier male weight, early arrival time and good nest quality were the best predictors of breeding success. The logistic regression approach used here showed that the predictive ability of these parameters varied as the season progressed. However, most importantly, our logistic models fit the data well across all breeding stages.