Crozet Islands Research Articles

Crozetia Davies (Diptera: Simuliidae): redescription of Cr. crozetensis, Cr. seguyi, number of larval instars, phylogenetic relationships and historical biogeography

The taxonomy of the genus Crozetia Davies (Diptera: Simuliidae) is reviewed. Apart from the eggs, all stages of Crozetia crozetensis (Womersley) and Cr. seguyi Beaucournu-Saguez and Vernon, are fully redescribed with only claws and genitalia detailed for the female of Cr. crozetensis. A phylogenetic analysis of the Simuliidae indicates that Crozetia is the sister group of all other members of the extant Simuliini, in agreement with current molecular evidence. Palaeogeological evidence on the age of the Crozet Islands is equivocal, but a very late Cretaceous to early Eocene age (79-54 Mya) is most likely, hence the presence of simuliids on this archipelago is not the result of vicariance from Gondwanaland. Method of dispersal to the Crozet Archipelago may have been via wind or possibly vectored by birds from Africa, as suggested by presence of a basal tooth on the adult female claw. Morphometric analysis of larvae of Cr. seguyi indicates seven instars which is typical for the Simuliidae.

Nocturnal predation of king penguins by giant petrels on the Crozet Islands

Dietary segregation of sympatric seabirds in the Southern Ocean is partly linked to differences in their foraging techniques. We have investigated the activity of giant petrels (Macronectes spp.) in a king penguin (Aptenodytes patagonicus) colony day and night during the austral winter of 2001 on the Crozet Islands. Using an automatic identification system and an infrared video camera, we followed 15 petrels tagged with micro transponders. Our data show that giant petrels predate king penguin chicks during the night. The activity of giant petrels is even slightly higher during nighttime than during the day. In addition, our data show a higher nocturnal activity by northern giant petrels (M. halli) than by southern giant petrels (M. giganteus). These unexpected results raise questions concerning visual adaptations to nocturnal foraging in giant petrels and their potential impact on the sleep, vigilance and creching behavior of penguin chicks.

Population Dynamics of the Wandering Albatross Diomedea Exulans at Marion Island: Longline Fishing and Environmental Influences

The subantarctic Prince Edward Islands (Marion and Prince Edward) support the largest breeding population of the Vulnerable wandering albatross Diomedea exulans. The number of birds breeding at Marion Island has fluctuated over the past three decades apparently as a result of both real changes in the size of the population and changes in the proportion of the population that attempts to breed in a given year. Changes in several demographic parameters that appear to be influenced by both environmental and anthropogenic effects are described. From 1994–2001, the proportion of first-time breeders in the population was positively correlated with the maximum ENSO (Niño 3) index, whereas from 1984–2000 the annual survival rates of breeding adults were negatively correlated with Japanese pelagic longline fishing effort in the southern Indian Ocean. Adult survival rates were significantly correlated with those on neighbouring Possession Island, Crozet Islands, but differed from those at South Georgia, suggesting common factors operating at an ocean-basin scale. The average survival rate of adult females was lower than that of males. Males who lost partners took 40% longer than females to find a new mate, suggesting a male-biased population. Survival rates of juvenile males and females did not differ. The age distribution of first-time breeders shifted progressively towards younger birds during the 1990s. Higher than expected survival rates of breeding adults during the late 1990s may be linked to large amounts of supplementary food being made available by the initiation of a longline fishery for Patagonian toothfish Dissostichus eleginoides close to the islands at this time. Overall, breeding success was better than recorded at other localities, indicating that breeding conditions at Marion Island were comparatively favourable. The early implementation of both international and national conservation initiatives to reduce the impact of longline fishing on this species and improve its conservation status is encouraged.

Contribution of alien and indigenous species to plant-community assemblages near penguin rookeries at Crozet archipelago

The influence of seabird colonies on a remote insular flora was investigated through the analysis of plant community patterns at the boundaries of three colonies of king penguins (Aptenodytes patagonicus) on the subantarctic Ile de la Possession. This study revealed that the physical and chemical impacts of these seabirds greatly influence plant assemblages (community composition, alien and native species abundance and richness). Plant richness appears to be maximum for a moderate disturbance intensity, on areas slightly influenced by penguin activities. The abundance of alien species near penguin rookeries may be due to their ability to withstand animal-induced disturbances and to efficiently colonise the stripped areas. In addition, the diversity and abundance of alien species recorded in study plots depend on the location of the colony. The closer the colony is to the permanent scientific station, the higher the number and abundance of aliens recorded.

Insular bird populations can be saved from rats: a long-term experimental study of white-chinned petrels Procellaria aequinoctialis on Ile de la Possession (Crozet archipelago)

The white-chinned petrel is a subantarctic seabird that requires urgent implementation of conservation measures for the species. At sea, adults suffer heavy mortality due to fisheries' practices. On land, introduced rats prey on chicks at several localities, and we test here if and how rats can be efficiently controlled. Since 1994, we have conducted an intensive rat-control program during each breeding season in a white-chinned petrel colony on Ile de la Possession (150 km2; Crozet archipelago, southern Indian Ocean), which had been monitored since 1986. On the same island, a control white-chinned petrel colony, where no poisoning occurred, was also monitored, and we assessed the seasonal variations of rat abundance. We compared three situations: high rat-poisoning, low rat-poisoning and control conditions without poisoning. Low-poisoning trials performed in our experimental colony between 1988 and 1991 did not lead to higher chick production than for the previous two control years. However, petrel-breeding success was significantly higher when intensive poisoning occurred (50%) than for the previous years (16%). The duration of our study (8 years before intensive poisoning, plus 8 years afterwards), combined with a comparison of petrel annual breeding success between our experimental and control colonies, allowed us to assess more effectively the impact of rats. Forty-one per cent of breeding failures occurring in non-poisoned areas were attributed to rats. We conclude that threatened insular bird populations can be conserved and restored in localities even where total rat eradication is not possible. However, only intensive and repeated (long-term) poisoning will control rats sufficiently.

Comparison of behaviour, body mass, haematocrit level, site fidelity and survival between infested and non-infested king penguin Aptenodytes patagonicus by ticks Ixodes uriae

The tick Ixodes uriae is widespread in subantarctic areas. This tick species parasitises a large number of seabird species and may affect their population dynamics. Adult king penguins are significant hosts for I. uriae in Crozet Archipelago. We compared the body mass, haematocrit level and behaviour during incubation according to tick infestation. Tick infestation had no effect on the body mass, haematocrit or behaviour of incubating penguins. Contrary to what might have been expected, birds breeding in the infested area did not show a lower fidelity to that area the next breeding season in comparison to birds breeding in the non-infested area. Survival was not different between the two groups over the following 32 months.

Geographic variation in the foraging behaviour, diet and chick growth of rockhopper penguins

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 251:279-297 (2003) - doi:10.3354/meps251279 Geographic variation in the foraging behaviour, diet and chick growth of rockhopper penguins Yann Tremblay*, Yves Cherel Centre d¹Etudes Biologiques de Chizé, UPR 1934 du Centre National de la Recherche Scientifique, BP 14, 79360 Villiers-en-Bois, France *Email: tremblay@cebc.cnrs.fr ABSTRACT: The foraging ecology of rockhopper penguins was investigated at 3 sites marked by contrasting ecological conditions. The northern subspecies was studied at Amsterdam Island (AMS) in oceanic subtropical waters, and the southern subspecies at the Kerguelen Archipelago (KER) in a subantarctic coastal habitat and at the Crozet Archipelago (CRO) in subantarctic neritic waters. During the brooding period, females from every site mainly made daily foraging trips lasting 11 to 12 h. A principal component analysis (PCA) on 22 variables of daily foraging trips reduced these variables to 3 principal components, which were related to diving mode (PC1), foraging effort (PC2) and variation in diving behaviour (PC3). Overall, PC1 indicated that birds from AMS dived shallower, had shorter dive duration and bottom time, and were less active during less efficient dives than birds from KER and CRO. On the other hand, PC3 showed that birds from KER segregated from those of AMS and CRO by performing more uniform foraging trips with less variability in dive parameters. The PCA emphasised that most of the characteristics of daily trips and all the characteristics of foraging dives varied according to the study sites, thus stressing the importance of distinct environments in shaping the foraging behaviour of seabirds. Food loads, and accordingly chick growth, were lower at AMS, medium at CRO and higher at KER, while indices of foraging effort presented little variation. Birds at AMS fed mainly on the euphausiid Thysanoessa gregaria and on larger juvenile squids, while birds from CRO and KER preyed upon the subantarctic krill Euphausia vallentini. Diving strategies together with food loads and chick growth rates suggest that prey availability was low at AMS, intermediate at CRO and high at KER, which is in agreement with previous data on chlorophyll concentrations and zooplankton biomass. The study shows the complexity of foraging behaviour of penguins. It illustrates the importance of behavioural plasticity and suggests that it is a fundamental trait of the life history of seabirds living in highly variable environments. KEY WORDS: Behavioural plasticity · Coastal · Diving behaviour · Thysanoessa gregaria · Eudyptes chrysocome · Oceanic · Neritic · Euphausia vallentini Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 251. Online publication date: April 11, 2003 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2003 Inter-Research.

FRUSTULIA CIRISIAE SP. NOV., A NEW AEROPHILOUS DIATOM FROM ILE DE LA POSSESSION (CROZET ARCHIPELAGO, SUBANTARCTICA)

The aerophilous diatom Frustulia cirisiae sp. nov. is described from the Subantarctic island He de la Possession (Crozet Archipelago). The detailed morphology of this species is examined using scanning electron microscopy (SEM). The taxonomic position of the new taxon is discussed, comparing it with similar freshwater genera such as Frustulia, Amphipleura and Stauroneis. Based on the presence of a stauros, so far an unknown feature within the genus Frustulia, a new subgenus Staurofrustulia is described.

Diurnal sleep depth changes in the king penguin (Aptenodytes patagonicus)

Avian sleep quality depends on its depth (deeper sleep being of better quality). In king penguins (Aptenodytes patagonica), sleep may be disturbed by congeners passing in the sleeper's vicinity. As king penguin activity is increased in the morning, sleep disturbances are more likely to occur during this time period. One might therefore assume that afternoon sleepers (AS) sleep more profoundly than morning sleepers (MS). To test this hypothesis, we examined the diurnal variations in sleep depth of king penguins sleeping in resting sites adjacent to the colony of ''La Baie du Marin'' (Crozet Archipelago). We measured the bodily tactile arousal threshold at the upper back level. The arousal threshold in AS was twice as high as in MS. This study demonstrates for the first time that sleep depth changes according to time of day in a diurnal wild bird. We postulate that diurnal sleep depth is increased due to decreased congener movements close to the sleeping penguin.

A new record of Limnognathia maerski Kristensen & Funch, 2000 (Micrognathozoa) from the subantarctic Crozet Islands, with redescription of the trophi

Abstract Limnognathia maerski, class Micrognathozoa, so far known only from Arctic Greenland, is reported from the subantarctic Crozet Islands. Fine morphology of the trophi is redescribed using scanning electron microscopy. Results show that the trophi are composed of the same functional units, i.e. incus, paired mallei and epipharynx, as found in Rotifera Monogononta. The zoogeography of the species is briefly discussed.

Soil diatom communities from Ile de la Possession (Crozet, sub-Antarctica)

An ecological study of soil diatoms on Ile de la Possession (Crozet Archipelago, sub-Antarctica) was carried out during the austral summer of 1998/1999. Both diatom and chemistry data were collected. A highly diverse diatom flora of 230 taxa, belonging to 39 genera were identified from 104 samples. Several of them are considered to be new. The most abundant genera were Diadesmis, Achnanthes and Pinnularia. Principal Component Analysis (PCA) was used to classify the samples based on their chemical characteristics. Moisture and nutrients were the main factors separating three groups of samples: dry fellfield soils, soils influenced by marine animals and mesic valley soils. Species assemblages correspond well with this division. Forward Selection with Monte Carlo permutations was used to reduce the number of significant variables. The analysis selected moisture, phosphate and sulphate concentrations. Based on the analysis, the same three groups of the PCA were found. Weighted averaging and calibration were used to develop a statistical transfer function to infer the moisture content of soils from the diatom assemblages.

Seasonal changes in the diving parameters of king penguins ( Aptenodytes patagonicus )

Contrasting conditions at-sea are likely to affect the foraging behaviour of seabirds. However, the effect of season on the dive parameters of penguins is poorly known. We report here on an extensive study of the diving behaviour of king penguins (Aptenodytes patagonicus) over the bird's complete annual cycle at the Crozet Islands. Time-depth recorders were used to record dive duration, bottom duration, post-dive interval, ascent rate and descent rate in breeding adults during different seasons in 1995 and 1996. Seasons included summer (n=6, incubation; n=6, chick brooding), autumn and winter (n=5 and n=3, respectively, chick at the creche stage), and spring (n=4, birds at the post-moult stage). In all seasons dive duration increased with dive depth, but, for a given depth, dives were longer in winter (6.8 min when averaged over the 100–210 m depth layer) than in spring (4.6 min) and summer (4.4 min). The time spent at the bottom of the dives, which probably represents a substantial part of the feeding time, was much longer in winter (2.5 min per dive for dives over the 100–210 m layer) than during other seasons (1.0–1.4 min), i.e. there was a 2.5-fold augmentation for similar diving depths. Ascent and descent rates increased with increasing dive depth, but no difference in the relationships between rates of ascent and descent and dive depth was found among seasons. Furthermore, for all dive depths, ascent and descent rates were independent of the bottom duration. In all seasons post-dive intervals increased with dive duration and with dive depth, but they were longer in spring (2.3 min for dives over the 100–210 m layer) and summer than in autumn and winter (1.6–1.8 min). The diving efficiency decreased with increasing dive depth and was higher in autumn and winter (0.22–0.29) than in summer and spring (0.15–0.18). The large increase in bottom and dive duration from spring to winter is in agreement with the seasonal drop in prey density, with penguins spending more time searching for prey. In contrast, the consistency of the vertical velocity during contrasting conditions at-sea suggests that the transit time to depth is an important component of the foraging behaviour (scanning of the water column) that is independent of the prey availability. The time budget of the penguins during diving in a fluctuating environment appears to vary primarily during the bottom phase of the dives, with bottom duration increasing with diminishing prey supplies, while post-dive intervals shorten in the same time.

Natural attenuation of diesel-oil contamination in a subantarctic soil (Crozet Island)

An accidental contamination occurred in subantarctic Crozet Island between July and November 1997 near the "Alfred Faure" scientific station (51°51′E–46°25′S). More than 20,000 l of diesel fuel was spilled in the soil in the vicinity of the power station. In order to evaluate the efficiency of the expected bioattenuation process, the contaminated area was sampled in December 1999 for bacterial and chemical analysis. All samples were analysed for total bacteria, heterotrophic viable assemblages and hydrocarbon-utilising microflora. The results of this first analytical survey clearly show a significant response of subantarctic microbial soil communities to the hydrocarbon contamination. Significant increases of total, heterotrophic and hydrocarbon-utilising micro-organisms occurred in the more contaminated zone (from less than 5×104 MPN g–1 wet soil to more than 108 MPN g–1 wet soil for hydrocarbon-degrading micro-organisms). The very high numbers of hydrocarbon-degrading micro-organisms present in the more contaminated zone are clearly linked to early bioattenuation activities. Chemical results provided some clear indications that spilled fuel was still well preserved from chemical and biological weathering 1 year after the spill, as light aliphatics and aromatics were present in all oiled samples and little differences were usually observed between samples.

Marine Rotifera from the Crozet and Kerguelen Islands (Subantarctica), with the Description of a New Encentrum(Monogononta: Dicranophoridae)

As part of a survey of the rotifer fauna of Terres Australes et Antarctiques Françaises, marine rotifers from the littoral of the subantarctic Grande Terre, Kerguelen archipelago and Ile de la Possession, Crozet archipelago are reported. Nine taxa were found: Bdelloidea indet. and eight Monogononta. One species, Encentrum frenoti, is new to science and described.

Foraging interactions between Wandering Albatrosses Diomedea exulans breeding on Marion Island and long‐line fisheries in the southern Indian Ocean

Wandering Albatrosses Diomedea exulans are frequently killed when they attempt to scavenge baited hooks deployed by long‐line fishing vessels. We studied the foraging ecology of Wandering Albatrosses breeding on Marion Island in order to assess the scale of interactions with known long‐line fishing fleets. During incubation and late chick‐rearing, birds foraged further away from the island, in warmer waters, and showed high spatial overlap with areas of intense tuna Thunnus spp. long‐line fishing. During early chick‐rearing, birds made shorter foraging trips and showed higher spatial overlap with the local Patagonian Toothfish Dissostichus eleginoides long‐line fishery. Tracks of birds returning with offal from the Toothfish fishery showed a strong association with positions at which Toothfish long‐lines were set and most diet samples taken during this stage contained fishery‐related items. Independent of these seasonal differences, females foraged further from the islands and in warmer waters than males. Consequently, female distribution overlapped more with tuna long‐line fisheries, whereas males interacted more with the Toothfish long‐line fishery. These factors could lead to differences in the survival probabilities of males and females. Non‐breeding birds foraged in warmer waters and showed the highest spatial overlap with tuna long‐line fishing areas. The foraging distribution of Marion Island birds showed most spatial overlap with birds from the neighbouring Crozet Islands during the late chick‐rearing and non‐breeding periods. These areas of foraging overlap also coincided with areas of intense tuna long‐line fishing south of Africa. As the population trends of Wandering Albatrosses at these two localities are very similar, it is possible that incidental mortality during the periods when these two populations show the highest spatial overlap could be driving these trends.

Serological survey of the king penguin, Aptenodytes patagonicus, in Crozet Archipelago for antibodies to infectious bursal disease, influenza A and Newcastle disease viruses

Sera from adult and chick king penguins were examined for antibodies to infectious bursal disease, influenza A and Newcastle disease viruses. This study was completed by a 1-year survey of clinical signs of disease in the colony. About 4% and 1% of the birds were positive for serotypes 1 and 2, respectively, of infectious bursal disease virus. In 1996, two coughing peaks occurred in adults, during autumn and spring, and a peak of conjunctivitis occurred at the end of the winter. Although this showed the presence of infectious agents, it was not possible to be precise about whether the detected viruses were responsible for the clinical signs, or to assess if the infectious agents were native or introduced.

Ontogeny of thermoregulatory mechanisms in king penguin chicks ( Aptenodytes patagonicus)

The rapid maturation of thermoregulatory mechanisms may be of critical importance for optimising chick growth and survival and parental energy investment under harsh climatic conditions. The ontogeny of thermoregulatory mechanisms was studied in growing king penguin chicks from hatching to the full emancipation observed at 1 month of age in the sub-Antarctic area (Crozet Archipelago). Newly hatched chicks showed small, but significant regulatory thermogenesis (21% rise in heat production assessed by indirect calorimetry), but rapidly became hypothermic. Within a few days, both resting (+32%) and peak (+52%) metabolic rates increased. The first week of life was characterised by a two-fold rise in thermogenic capacity in the cold, while thermal insulation was not improved. During the second and third weeks of age, thermal insulation markedly rose (two-fold drop in thermal conductance) in relation to down growth, while resting heat production was slightly reduced (−13%). Shivering (assessed by electromyography) was visible right after hatching, although its efficiency was limited. Thermogenic efficiency of shivering increased five-fold with age during the first weeks of life, but there was no sign of non-shivering thermogenesis. We conclude that thermal emancipation of king penguin chicks may be primarily determined by improvement of thermal insulation after thermogenic processes have become sufficiently matured. Both insulative and metabolic adaptations are required for the rapid ontogeny of thermoregulation and thermal emancipation in growing king penguin chicks.

The Decline of the Albatross

ECOLOGY Populations of the wandering albatross species in the Southern Ocean have been declining for several decades. Commercial longline fishing for tuna (by-catch”) has been implicated in this decline; albatrosses often attempt to remove bait from fishing lines, the unsuccessful ones becoming entrapped themselves. However, because of the vast distances covered by albatrosses while foraging, it has proved difficult to establish the quantitative relationship between the distribution of longline fishing and albatross foraging. Tuck et al. adopt a modeling approach to assess the impact of fishery by-catches on albatross populations, using 30-year data sets on albatross populations at two important breeding sites and parallel reported data on fishing activities in albatross foraging areas. The resulting simulations of albatross population dynamics appear to confirm a substantial impact of by-catch on one of the study populations (Crozet Islands), but indicate a less definite link with the observed population declines at the other (South Georgia). These models allow the integration of demographic and fishing data in a way that is impossible to achieve through direct observation, and, when developed further, will help to pinpoint regulatory and conservation priorities for the Southern Ocean. — AMS J. Appl. Ecol. 38, 1182 (2001).

Heart rate and energy expenditure of incubating wandering albatrosses: basal levels, natural variation, and the effects of human disturbance.

We studied the changes in heart rate (HR) associated with metabolic rate of incubating and resting adult wandering albatrosses (Diomedea exulans) on the Crozet Islands. Metabolic rates of resting albatrosses fitted with external HR recorders were measured in a metabolic chamber to calibrate the relationship between HR and oxygen consumption (V(O(2))) (V(O(2))=0.074 x HR+0.019, r(2)=0.567, P<0.001, where V(O(2)) is in ml kg(-1) min(-1) and HR is in beats min(-1)). Incubating albatrosses were then fitted with HR recorders to estimate energy expenditure of albatrosses within natural field conditions. We also examined the natural variation in HR and the effects of human disturbance on nesting birds by monitoring the changes in HR. Basal HR was positively related to the mass of the individual. The HR of incubating birds corresponded to a metabolic rate that was 1.5-fold (males) and 1.8-fold (females) lower than basal metabolic rate (BMR) measured in this and a previous study. The difference was probably attributable to birds being stressed while they were held in the metabolic chamber or wearing a mask. Thus, previous measurements of metabolic rate under basal conditions or for incubating wandering albatrosses are likely to be overestimates. Combining the relationship between HR and metabolic rate for both sexes, we estimate that wandering albatrosses expend 147 kJ kg(-1) day(-1) to incubate their eggs. In addition, the cost of incubation was assumed to vary because (i) HR was higher during the day than at night, and (ii) there was an effect of wind chill (<0 degrees C) on basal HR. The presence of humans in the vicinity of the nest or after a band control was shown to increase HR for extended periods (2-3 h), suggesting that energy expenditure was increased as a result of the disturbance. Lastly, males and females reacted differently to handling in terms of HR response: males reacted more strongly than females before handling, whereas females took longer to recover after being handled.

SPATIAL AND TEMPORAL VARIABILITY IN THE FORAGING AREAS OF BREEDING KING PENGUINS

King Penguins (Aptenodytes patagonicus) from breeding islands in the Indian Ocean (Crozet and Kerguelen Islands) and the Atlantic Ocean (South Georgia and Falkland Islands) were equipped with global location sensors to compare their foraging patterns during different times of the year. In summer, all birds investigated traveled toward the Antarctic Polar Front (APF), irrespective of whether they bred to the north (Crozet Islands, Falkland Islands), within (Kerguelen Islands) or to the south (South Georgia) of this hydrographic feature. Whereas most birds remained north of the APF and foraged in waters of the Antarctic Polar Frontal Zone, some penguins also traveled, or remained (South Georgia), south of the APF and foraged in Antarctic waters. It appeared that food resources in the vicinity of the APF were sufficiently predictable to warrant travel of several hundred km by King Penguins for foraging. Data collected on the winter distribution of King Penguins indicated at least two different foraging strategies. Birds from the oceanic Crozet Islands foraged beyond the APF in the Antarctic waters, whereas birds from the Falkland Islands relied also on the resources provided by the highly diverse and productive slope of the Patagonian Shelf. However, despite these differences, in both cases minimum distances of sometimes more than 10 000 km were covered. Further research on the foraging habitats of King Penguins over the entire breeding season and the temporal and spatial changes of oceanographic features is necessary to obtain a comprehensive picture on the variability in the foraging ranges of King Penguins. Variabilidad Espacial y Temporal en las Áreas de Forrajeo de Individuos Reproductivos de Aptenodytes patagonicus Resumen. Comparamos los patrones de forrajeo de individuos reproductivos de Aptenodytes patagonicus provenientes de las islas del Océano Índico (Islas Crozet y Kerguelen) y Océano Atlántico (Islas Georgia del Sur y Malvinas) durante diferentes períodos del año, equipando pingüinos con sensores de localización global. En el verano, todas las aves investigadas viajaron hacia el Frente Polar Antártico (FPA), independientemente de si se reprodujeron al norte (Islas Crozet, Islas Malvinas), en (Islas Kerguelen) o al sur (Islas Georgias del Sur) de aquella entidad hidrográfica. Aunque la mayoría de las aves permanecieron al norte del FPA y forrajearon en aguas de la Zona Polar Frontal Antártica, algunos pingüinos también viajaron hacia el sur del FPA y forrajearon en aguas antárticas. Al parecer los recursos alimenticios en el FPA fueron lo suficientemente predecibles como para justificar que los pingüinos viajen varios cientos de kilómetros para forrajear. Los datos colectados durante la distribución de invierno de A. patagonicus indicaron por lo menos dos estrategias de forrajeo diferentes. Las aves provenientes de las islas oceánicas Crozet forrajearon más allá del FPA en aguas antárticas, mientras que las aves provenientes de las Islas Malvinas dependieron además de los recursos que provee la diversa y productiva plataforma marítima patagónica. Sin embargo, a pesar de estas diferencias, en ambos casos a veces las aves cubrieron distancias mínimas de más de 10 000 km. Para obtener un panorama completo sobre la variabilidad en los rangos de forrajeo de A. patagonicus es necesario efectuar más investigaciones sobre los hábitats de forrajeo de estos pingüinos durante la totalidad de la época reproductiva y durante todos los cambios temporales y espaciales de las entidades hidrográficas.