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Antarctic and Sub-Antarctic pinnipeds are well-known seasonal visitors of the Southwest Atlantic Ocean. According to the literature, at their breeding grounds, they feed mainly on a variety of fish, cephalopods, and crustaceans. During the non-breeding period and far away from its breeding colonies, little is known about their feeding habits. Here, we present records of predation on aquatic birds by Antarctic and Sub-Antarctic pinnipeds off northern Argentinian coast (37°27′ S, 57°06′ W to 41°50' S 65°02' W). We examined the gastrointestinal contents of 22 specimens of three pinnipeds species (Arctocephalus gazella [n = 10], A. tropicalis [n = 11] and Hydrurga leptonyx [n = 1]) collected from 1996 to 2023. Aquatic birds remains were found in the gastrointestinal tracts of three individuals (13.64%): two A. gazella and one H. leptonyx. We identified feathers, and other bird parts by comparing them to specimens from scientific collections and descriptions/illustrations from the literature. Two of the three aquatic birds found in the gastrointestinal tracts were most probably Magellanic Penguins (Spheniscus magellanicus), whereas the other one was a Great grebe (Podiceps major). To our knowledge, this is the first study reporting predation on aquatic birds by Antarctic pinnipeds far from their breeding colonies. [ABSTRACT FROM AUTHOR]

Southern giant petrels (Macronectes giganteus) are important consumers that range across the oceans throughout the southern hemisphere. In Argentina, previous studies have shown they eat primarily pinnipeds and penguins, which they are assumed to scavenge, although there are occasional anecdotes of them attacking living penguins. Here we describe a predation attempt by a trio of southern giant petrels on a molting adult Magellanic penguin (Spheniscus magellanicus) at the large colony at Punta Tombo, Argentina. We relate giant petrel attendance patterns at the colony to the penguins' phenology, showing how giant petrel numbers rise with the increasing prevalence of vulnerable penguins. We suggest that living penguins—both fledglings and adults—may constitute a more seasonally significant proportion of the giant petrel diet than previously assumed, and their capture may represent a specialized predation technique. [ABSTRACT FROM AUTHOR]

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Abstract Southern giant petrels (Macronectes giganteus) are important consumers that range across the oceans throughout the southern hemisphere. In Argentina, previous studies have shown they eat primarily pinnipeds and penguins, which they are assumed to scavenge, although there are occasional anecdotes of them attacking living penguins. Here we describe a predation attempt by a trio of southern giant petrels on a molting adult Magellanic penguin (Spheniscus magellanicus) at the large colony at Punta Tombo, Argentina. We relate giant petrel attendance patterns at the colony to the penguins' phenology, showing how giant petrel numbers rise with the increasing prevalence of vulnerable penguins. We suggest that living penguins—both fledglings and adults—may constitute a more seasonally significant proportion of the giant petrel diet than previously assumed, and their capture may represent a specialized predation technique.

Seabirds coexist within colonies yet the role of conspecifics, whilst foraging is still poorly understood. In the 2019/20 and 2020/21 breeding seasons Magellanic penguins Spheniscus magellanicus and Gentoo penguins Pygoscelis papua were equipped with video loggers and GPS devices (n = 3 and n = 2, respectively) or only GPS devices (n = 11 and n = 2) at Martillo Island (54°54′ S, 67°23′ W), Argentina and compared with GPS tracks from previous seasons (2014, 2015 and 2017). Magellanic penguins transited in groups with conspecifics to the feeding grounds (up to 13 individuals were recorded simultaneously) in search of pelagic Fuegian sprat Sprattus fuegensis, but then were not filmed in close company of conspecifics during prey capture. Gentoo penguins generally fed on Nototheniid sp. at the seafloor. Contrary to predictions, Gentoo penguins foraged with conspecifics in small groups of 2–4 individuals, they coordinated to dive down, search and ambush prey. Gentoo penguins were also recorded foraging pelagically on Fuegian sprat. Conspecifics play an important role either during the initial search for prey patches, particularly when searching for elusive pelagic prey or during the small-scale search and hunt for benthic prey hidden in the seafloor substrate. The presence of conspecifics seems to be important during foraging for Magellanic and Gentoo penguins and this may be reflecting a positive aspect of coloniality. [ABSTRACT FROM AUTHOR]

Wildlife tourism is increasing worldwide and monitoring the impact of tourism on wild populations is of the utmost importance for species conservation. The Magellanic penguin Spheniscus magellanicus colony at Martillo Island, Argentina, was studied in the 2016–2020 breeding seasons. In all seasons, adults and chicks belonged to: (i) an area close to or within the tourist trail or (ii) an area far from the tourist trail and out of sight of the tourists. Blood samples were taken for carbon and nitrogen stable isotope composition, in order to estimate trophic niches, and for smears that were made in situ and were then stained in the laboratory where leucocyte counts and differentiation were made under optical microscope. Heterophil to lymphocyte ratios were used as proxies of stress. Repeated sampling showed individual stress levels reduced while wintering. In 2017, stress levels and trophic values were lower than 2018 for the same individuals. Trophic levels did not differ between tourism and no tourism areas within each season, and differed between 2017 and the remaining seasons, indicating a possible diet shift that year. Stress levels were higher for the tourism area than the no tourism area for adults and chicks in all years except for 2020, when stress levels in the tourism area were lower and similar to the no tourism area that year and previous years. Vessel transit within the Beagle Channel and tourist visitation to the penguin colony was greatly reduced in 2020 due to the Covid-19 pandemic. A combination of internal characteristics and external factors may be affecting the stress physiology of individuals. Therefore, future research should include sampling of multiple aspects of penguin physiology, behaviour and environmental context in order to evaluate each effect on Magellanic penguin stress and, ultimately, inform the conservation of this iconic species in time. [ABSTRACT FROM AUTHOR]

Divorce among serially monogamous birds can lead to increased reproductive success if an individual obtains a higher-quality mate or nest site, or it can lead to lower reproductive success due to lack of pair experience or reduced breeding opportunities. Identifying the drivers and consequences of mate retention and divorce are necessary then to understand population dynamics, particularly as animals may alter behaviours in response to climate-induced environmental changes. We used a 33-year data set from a declining Magellanic penguin, Spheniscus magellanicus , colony to identify drivers of mate retention and divorce and test whether the nature of those drivers differed between first-year and long-term pairs. In a pair's first year, breeding outcome was the most important predictor of whether mates would reunite: failure rates were high and 71% of first-year pairs divorced on the whole, but only 47% of pairs that fledged a chick divorced. For long-term pairs, both breeding outcome and between-season changes to nest quality were the most important predictors of whether a pair stayed together: pairs that had a chick hatch or fledge divorced at lower rates than those that failed at the egg stage, and pairs whose nest quality declined were more likely to divorce. We also examined the fitness consequences of divorce by comparing the rates at which females and males obtained new mates and fledged chicks in the following year. Although females were more likely than males to secure a new mate, both sexes experienced similarly increased reproductive success with their new mates compared to their old mates, showing that divorce is adaptive. • We examined factors driving mate retention and divorce in Magellanic penguins. • First-year pairs that fledged a chick were more likely to reunite. • Chick hatching/fledging and nest quality significantly affected mate retention. • Females were more likely to obtain new mates following divorce. • Reproductive success with new mates did not differ between the sexes. [ABSTRACT FROM AUTHOR]

Understanding how animals move in dense environments where vision is compromised is a major challenge. We used GPS and dead-reckoning to examine the movement of Magellanic penguins commuting through vegetation that precluded long-distance vision. Birds leaving the nest followed the shortest, quickest route to the sea (the 'ideal path', or 'I-path') but return tracks depended where the birds left the water. Penguins arriving at the beach departure spot mirrored the departure. Most of those landing at a distance from the departure spot travelled slowly, obliquely to the coast at a more acute angle than a beeline trajectory to the nest. On crossing their I-path, these birds then followed this route quickly to their nests. This movement strategy saves birds distance, time and energy compared to a route along the beach and the into the colony on the I-track and saves time and energy compared to a beeline trajectory which necessitates slow travel in unfamiliar areas. This suggests that some animals adopt tactics that take them to an area where their navigational capacities are enhanced for efficient travel in challenging environments. [ABSTRACT FROM AUTHOR]

Most seabirds forage far from land, making them hard to observe when foraging. Satellite tracking of seabirds shows where they come into conflict with human uses of the ocean, and whether they use protected areas. Because tracking data are expensive, data from one colony and/or year are sometimes used to design marine protection for a species across its range. Two assumptions commonly made are that foraging distance increases with colony size and individuals are uniformly distributed around colonies. We tested these assumptions using Magellanic penguins Spheniscus magellanicus as an example. We used a large tracking dataset of 338 penguins foraging for chicks at 10 colonies in Argentina from 1996 to 2019. Foraging distance increased with population size among colonies, but predicted distances would not cover foraging areas for all colonies. There was no relationship between population size and foraging distance within colony among years for colonies with ten and 23 years of data. Penguins were not uniformly distributed around colonies. Penguins used ~24% (12-40%) of the ocean available within the colony’s maximum foraging distance. We also show that overlap between penguin foraging areas and marine protected areas (MPA) and hydrocarbon concessions varied among colonies partly because of variation in how far offshore penguins forage. Overlap with MPAs was low (0% – 20%) for seven of the ten colonies and high (23% – 100%) for the other three. Overlap with a large area permitted for hydrocarbon exploration (seismic surveys) was relatively high (23% – 81%) for seven colonies where penguins forage offshore. Data from one colony are unlikely to indicate the most effective marine spatial planning for all colonies. Our data show that to be effective, marine planning should consider the temporal and spatial dynamics of ocean conditions and the response of marine wildlife to these changes. Climate variability is predicted to increase, making knowledge of foraging-location variation among colonies and years critical to conservation planning.

Extreme weather events are becoming more frequent and severe, leading to an increase in direct, adverse thermoregulatory impacts on wildlife. Here, we document an unprecedented, single-day, heat-related mortality event of Magellanic Penguins (Spheniscus magellanicus) at Punta Tombo, Chubut Province, Argentina, one of the largest breeding colonies for this species. We found 264 dead adults and 90 dead chicks in the breeding colony and along the beaches after recording the highest temperature in the shade (44°C on January 19, 2019) since the study started in December 1982. We found dead adults and chicks in postures used to release heat (i.e. lying prone with flippers and feet extended away from the body and/or bills open). We found no evidence for other causes of mortality other than heat (e.g., disease, toxic algae, starvation). Adults potentially died of dehydration, because dead adults were in significantly worse body condition than adults that survived. Dead adults had either empty stomachs or <50 g of food, and 27% of the dead adults died traveling between the nesting area and the water. More males died than females (83% male and 17% female; n = 94). In one section of the colony, ~5% of 1,153 adults died in the heat. Mortality rates of adults were unevenly distributed across the colony, suggesting that the presence of microclimates or easier beach access was an important factor to penguin survival. The body condition indices of dead and live chicks were similar and chicks that died from heat had food in their stomachs (mean = 405 ± 128 g; n = 14), suggesting that food likely inhibited their ability to thermoregulate. Documenting the effects of extreme weather events on populations is crucial to predicting how they will respond to climate change because these events, although rare, are expected to become more frequent and could have severe impacts on populations. [ABSTRACT FROM AUTHOR]

The overall population size and trend of the Magellanic Penguin (Spheniscus magellanicus) is uncertain and population estimates are available only for few locations. The last complete census along its central-southern distribution range in Argentina, province of Santa Cruz, was made in the 1990s. This study updates the breeding population size along Santa Cruz. Population estimates were compared with the last complete census, and trends were studied when it was possible. With 353,256 estimated breeding pairs, the overall population in Santa Cruz remained relatively stable after 25 years. The Santa Cruz population represents 31% of the Argentine Patagonian coast population and could represent between 22 and 30% of the species' global population. Colony sizes varied between 9 and 127,492 breeding pairs. Changes in abundance differed among locations, with individual colonies showing increasing, decreasing, or stable trends, which suggests that local factors determine population dynamics. The most significant increases (> 40%) were observed in the southern sector of Santa Cruz. Contrary to what was observed at the north of the distribution range in the province of Chubut, where trends of several colonies were inversely related to colony size, in Santa Cruz most of the largest colonies remained stable or even increased from the 1990s onwards. [ABSTRACT FROM AUTHOR]

Sub-Antarctic fur seals, Arctocephalus tropicalis, are widely distributed in the southern hemisphere, breeding on islands north of the Antarctic Convergence in the South Atlantic, South Indian, and Southwestern Pacific Oceans. At their breeding grounds, sub-Antarctic fur seals feed on a variety of fish, cephalopods, crustaceans, and occasionally, on penguins. According to the literature, the species feeds mainly on squid and fish, in the southern Brazilian coast, during the non-breeding period and far away from its breeding colonies. Here, we present records of predation on penguins by sub-Antarctic fur seals off southern Brazilian coast (29°20′S, 49°43′W to 33°44‵S, 53°22′W). We examined the gastrointestinal contents of 61 sub-Antarctic fur seals collected from 1987 to 2019. Remaining of penguins were found in the gastrointestinal tracts of three adult males (4.9%). We identified feathers, and other bird parts by comparing them specimens from scientific collections and illustrations in the literature. Seabirds found in the gastrointestinal tracts of the three sub-Antarctic fur seals were most probably Magellanic Penguins, Spheniscus magellanicus. To our knowledge, this is the first study reporting predation on penguins by sub-Antarctic fur seals far from their breeding colonies. Although penguins are not among the main prey of sub-Antarctic fur seals, our results suggest that they occasionally feed on penguins during the non-breeding period along the southern coast of Brazil. [ABSTRACT FROM AUTHOR]

Phenological shifts may ameliorate negative effects of climate change or create carryover effects and mismatches that decrease fitness. Identifying how phenological shifts affect performance is critical for understanding how individuals and populations will respond to climate change, but requires long‐term, longitudinal data. Using 34 yr of data from the Magellanic penguin (Spheniscus magellanicus) colony at Punta Tombo, Argentina, we examined the consequences of the delayed onset of breeding (i.e., arrival and egg‐laying dates) that has occurred at the colony since 1983. To understand how the delay propagates through the rest of the reproductive cycle, we identified phenological trends in hatch and fledge dates. Median hatch dates were 0.29 d later each year, amounting to a 10‐d shift over the course of the study. Median fledge dates did not shift over the 34‐yr period, however, thus shortening the median nestling period duration by 14%. We tested several predictions regarding performance outcomes of the compressed nestling period, finding that later‐hatched chicks fledged significantly younger than earlier‐hatched chicks, and that younger fledglings left the colony with smaller bills and with more chick down. Interestingly, although younger chicks fledged significantly lighter and in worse body condition than older fledglings early in the study, this trend reversed over time, with younger chicks actually fledging heavier and in better body condition in more recent years. Smaller and lighter fledglings were less likely to recruit to the colony as adults. We find that delayed breeding has significantly compressed nestling periods at Punta Tombo, influencing chick growth and fledgling condition. These findings highlight the importance of studying phenology across multiple life events to understand the consequences of phenological shifts for organismal fitness. [ABSTRACT FROM AUTHOR]

A 7-month-old, male Magellanic penguin (Spheniscus magellanicus), housed in an outdoor exhibit, developed acute neurologic signs that progressed to death over 2 days. On gross examination, the bird had congested, edematous lungs, and cerebellar hemorrhage. Histologic examination identified granulomatous pneumonia and encephalitis, with thrombosis and eosinophilic, branching fungal hyphae that had invaded the meningeal vessel walls. Polymerase chain reaction identified the fungus in the brain as Rhizomucor pusillus, an uncommon cause of mucormycosis. This organism has previously been reported in respiratory, skeletal, and sino-orbital lesions of avian species. This clinical report describes meningoencephalitis associated with Rhizomucor pusillus in a penguin. [ABSTRACT FROM AUTHOR]

Marine Protected Areas (MPAs) are gaining wide support as a management and conservation mechanism. MPAs target everything from a single species to an entire ecosystem and although success in achieving desired management goals varies on a case-by-case basis, their implementation has significantly changed management paradigms for the better. In southern Chile, Puñihuil Islets contain the largest described mixed-species colonies of Spheniscus penguins. Humboldt (Spheniscus humdoldti) and Magellanic (S. magellanicus) penguins breed here sympatrically and provide an unprecedented opportunity to understand the successful resource partitioning between these closely related species. This region is also economically important for fisheries, such as Chilean abalone, mussel and corvine, as well as for ecotourism. Because bycatch in the coastal gillnet fishery has historically been described during the breeding season, we propose a framework for establishing a MPA based on the biology of the penguins. During chick rearing, foraging behavior based on 12 Humboldt and 10 Magellanic penguins tagged with GPS TD loggers indicates that the birds occupied an area at sea up to 106 km2. After molting, between April and August, it has been described that certain individuals disperse over a coastal area ranging from the breeding site 1000 km to the north and return to the colony for breeding activities. We therefore recommend a time-sensitive MPA whereby coastal gillnets are not allowed to fish in this area during this time. We further provide diverse MPA options where boundaries and sizes were created based on the utilization areas at-sea during early chick rearing.

Variation in the foraging strategies used among species is a key factor in determining the trophic structure of ecological communities. Moreover, foraging niche differentiation could be driven by inter-specific competition and/or variation within species due to seasonal, age, sex and/or individual factors. Using stable isotope analysis, we assessed inter- and intra-specific differences in the foraging niches of female Southern Rockhopper penguin (Eudyptes chrysocome; SRP) and male and female Magellanic penguins (Spheniscus magellanicus; MP) at Isla de los Estados, Argentina. We sampled whole blood and feathers from breeding adults, representing the breeding and pre-moult periods over two consecutive years (2012 and 2013). We also compared stable isotope values between tissue to test for consistency in individuals foraging niches and the potential for foraging niche specialisation and segregation within breeding pairs. We observed clear foraging niche segregation between species that persisted during both breeding and pre-moult periods. SRP foraged in more oceanic/pelagic waters (lower δ13C values) while MP used coastal/benthic foraging habitats (higher δ13C values). In addition, SRP fed on lower trophic level prey (low δ15N values) relative to MP during both time periods. The isotopic foraging niches of MP highly overlapped between sexes at the population level and there was little to no evidence of niche segregation within breeding pairs or individual consistency in the seasonal foraging niche of both species. The results suggest that inter-specific foraging niche segregation is likely a more important factor influencing the trophic ecology and foraging behaviours of these species, relative to intra-specific factors. Even so, the persistence of inter-specific foraging niche segregation outside the breeding season suggests that either the potential for competition for food resource or foraging habitats remain high during this time or that the ultimate factors responsible for foraging niche segregation among these two species may be unrelated to these proximate factors. [ABSTRACT FROM AUTHOR]

The Magellanic Penguin Spheniscus magellanicus is one of the main seabird predators in the western South Atlantic. This species presents an opportunist feeding behaviour and its diet, as well as its parasite fauna, varies geographically depending on available prey and intermediate hosts. Despite thousands of Magellanic Penguins being found dead every year in southern Brazil, little attention has been given to their parasite–host interactions in this area. In this context, the aim of the present study was to assess the relationship between Magellanic Penguin diets and gastrointestinal helminth fauna at different age classes and body conditions in southern Brazil. To this end, the gastrointestinal tracts of 63 Magellanic Penguins found dead in 2013 and 2014 were examined. All individuals were parasitized by at least one species and only one penguin did not contain any food remains. A total of 138,209 helminths comprising eight species were found. Moreover, 12 prey species were recorded, including six fish and six cephalopod taxa. The helminth component community composition of juvenile penguins was similar to that of adults but the structure differed according to penguin age class. Cephalopod and crustacean prey species were significantly more frequent in juveniles compared to adults. Adults preyed mainly upon fishes. It was evident that lean individuals, both juveniles and adults, are more intensely infected in southern Brazil. Therefore, the high abundance of helminth parasites and the consumption of less energy-efficient prey cannot be ruled out as contributory factors to the high mortality of this species, mainly lean juveniles, in this area. [ABSTRACT FROM AUTHOR]

The present study offers the first description of proventriculitis associated with the presence of gravid female nematodes of the genus Tetrameres (Nematoda: Tetrameridae) in 3 juvenile Magellanic penguins (Spheniscus magellanicus) found dead on the coast of Brazil. This study broadens knowledge on parasites associated with these hosts and the real impact of this association. [ABSTRACT FROM AUTHOR]

Seabirds have been widely used for monitoring the health of the oceans in diverse marine regions. Among low-cost survey strategies, systematic surveys of seabirds beached on coasts have been developed since the 20th century. However, these studies do not always address blood aspects. The assessment of the health status of birds based on the analysis of hematological and plasma chemistry is crucial to evaluate the overall health status profile of live organisms. Here, the authors study the variability of blood parameters by sex, age class, and year of beached Magellanic Penguin during the nonreproductive period in northern Argentina. Of 44 penguins, 77% were categorized as younger juveniles and the rest as older juveniles, and were captured and studied in coastal areas of Buenos Aires Province during the summers of 2017 and 2018. The mean body weight of beached penguins was affected by the age class of the individuals; most of the younger juveniles showed poor condition in terms of body mass (1,761 ± 235 g). No significant differences were observed in body weight between years and sex. Still, there were significant differences between years for alkaline phosphatase (ALP) and creatine phosphokinase (CPK) values. Twelve of the 20 blood parameters analyzed differ significantly with the age class of the beached penguins; younger juveniles were in a state of inanition. Our results may serve as a necessary first step in improving the conservation status of the Magellanic Penguin in nonbreeding grounds of Argentina, and call for a better knowledge of the health status of the species along its annual cycle. [ABSTRACT FROM AUTHOR]

Bycatch in gillnet fisheries is one of the main threats to several penguin species. Magellanic penguins (Spheniscus magellanicus) are caught by gillnets during their wintering in southern Brazil. However, current information is based only on a small number of sets observed during a single fishing trip.This study assesses bycatch rates of bottom and drift gillnets operating in southern Brazil, and describes the sex and age classes of individuals captured.In 80 bottom gillnet sets, 33 penguins were captured (85% adults), 14 were sexed of which 13 were females. In 41 drift gillnet sets, four penguins were captured, three of which were juveniles.The mean bycatch rates, measured as number of penguins km−2 of net and number of penguins km−2 h−1, were significantly higher for the drift gillnets.Despite the lower bycatch rates, owing to the higher fishing effort in terms of number of boats, net length, net area, soak time and fishing season, the magnitude of penguin bycatch in the bottom gillnet fishery cannot be ignored.Despite based on small sample size, the predominance of adult and female Magellanic penguins as bycatch in gillnet fisheries in southern Brazil agrees with previous studies suggesting that females displace further north than males. In addition, such evidence contributes to the male‐biased sex ratio in breeding grounds, and the long‐term decline of major Patagonian colonies owing to higher female mortality during winter. [ABSTRACT FROM AUTHOR]

Prey use by male and female Magellanic Penguins (Spheniscus magellanicus) was quantified during chick rearing in northern Golfo San Jorge, Argentina and the dietary niches and diet composition of each sex were assessed and compared. A total of 67 males and 45 females were flushed during the chick stages of 2011 and 2012. Argentine Anchovy (Engraulis anchoita) was the main prey in terms of importance by mass in males and females in all stages and years (52.4–86.6% and 83.8–88.7%, respectively), except during the old chick stage in 2011 when the main prey in males and females was the Shortfin Squid (Illex argentinus) (63.1% and 44.4%, respectively). Analyses of similarity showed that diet composition in terms of contribution by mass of the main prey species was similar between sexes. Based on the isotopic values of δ13C and δ15N corresponding to 38 males and 21 females, the Bayesian mixing model outputs showed that Argentine Anchovy was also the main prey. In both years and chick stages, the isotopic niche of males and females was similar. The similarity in the dietary niche between male and female Magellanic Penguins raising chicks may be due to the high availability of Argentine Anchovy during the study period and the consequent dominance of this forage species in the diet of both sexes. [ABSTRACT FROM AUTHOR]

Lateralization, or asymmetry in form and/or function, is found in many animal species. Brain lateralization is considered adaptive for an individual, and often results in “handedness,” “footedness,” or a side preference, manifest in behavior and morphology. We tested for lateralization in several behaviors in a wild population of Magellanic penguins Spheniscus magellanicus breeding at Punta Tombo, Argentina. We found no preferred foot in the population (each penguin observed once) in stepping up onto an obstacle: 53% stepped up with the right foot, 47% with the left foot (n = 300, binomial test p = 0.27). We found mixed evidence for a dominant foot when a penguin extended a foot for thermoregulation, possibly depending on the ambient temperature (each penguin observed once). Penguins extended the right foot twice as often as the left foot (n = 121, p < 0.0005) in 2 years when we concentrated our effort during the heat of the day. In a third year when we observed penguins early and late in the day, there was no preference (n = 232, p = 0.59). Penguins use their flippers for swimming, including searching for and chasing prey. We found morphological evidence of a dominant flipper in individual adults: 60.5% of sternum keels curved one direction or the other (n = 76 sterna from carcasses), and 11% of penguins had more feather wear on one flipper than the other (n = 1217). Right-flippered and left-flippered penguins were equally likely in both samples (keels: p = 0.88, feather wear: p = 0.26), indicating individual but not population lateralization. In fights, aggressive penguins used their left eyes preferentially, consistent with the right side of the brain controlling aggression. Penguins that recently fought (each penguin observed once) were twice as likely to have blood only on the right side of the face (69%) as only on the left side (31%, n = 175, p < 0.001). The proportion of penguins with blood only on the right side increased with the amount of blood. In most fights, the more aggressive penguin used its left eye and attacked the other penguin’s right side. Lateralization depended on the behavior tested and, in thermoregulation, likely on the temperature. We found no lateralization or mixed results in the population of Magellanic penguins in three individual behaviors, stepping up, swimming, and thermoregulation. We found lateralization in the population in the social behavior fighting. [ABSTRACT FROM AUTHOR]

Anisakid nematodes have a worldwide distribution and are associated with fishes, birds, and marine mammals from freshwater, brackish, and marine systems. The aims of this work are to report for the first time Contracaecum mirounga parasitizing the Magellanic penguin Spheniscus magellanicus, to report another Contracaecum species in the same host species, and to discuss the validity of Contracaeceum spheniscus. Several dead chicks, juveniles, and adults of S. magellanicus were collected along the Argentinean coast from 2002 to 2009. Nematodes were removed from digestive tracts and studied using both light and scanning electron microscopy. Nematode prevalences were 2.38% for C. mirounga and 12.5% for Contracaecum sp. Contracaecum mirounga was found in 1 penguin from Península Valdés, Chubut. This species is known as a specific parasite of marine mammals such as Pinnipedia, thereby suggesting that this nematode is not as specific as believed. Another species of Contracaecum sp. was found parasitizing 1 penguin from the Río de la Plata coast. It possessed an unusual interlabial morphology and arrangement of male caudal papillae. Despite the low prevalence, the distinct morphological features are convincing and support the presence of a new Contracaecum species. However, a formal description is not presented because sufficient male specimens are lacking. Finally, C. spheniscus is considered a junior synonym of Contracaecum pelagicum. Future molecular studies might be helpful to determine the real diversity of Contracaecum species parasitizing S. magellanicus considering the number of sibling species recognized among the anisakids. [ABSTRACT FROM AUTHOR]

Blood parameters (hematology and biochemistry) are useful in assessing the physiological, nutritional, and overall health status of both captive and free-ranging wildlife. In this study, we established baseline values for blood parameters (hematology, plasma biochemistry, and trace elements) of free-ranging adult Magellanic Penguins (Spheniscus magellanicus) sampled at ten breeding colonies covering their full latitudinal distribution in Patagonia over two decades. Males had higher packed cell volume, heterophil and eosinophil relative counts, total solids, copper, and iron but lower magnesium than females. We also compared our results with those obtained in previous studies on both captive and free-ranging Magellanic Penguins and other Spheniscus species. Our study provides a baseline for ecological studies investigating the physiological responses of this species to natural and anthropogenic changes. Furthermore, our findings provide clinically relevant reference values for Magellanic Penguins under care at zoos, aquaria, and rehabilitation centers. [ABSTRACT FROM AUTHOR]

In a food-limited system, parents may have to allocate resources in ways that do not benefit all their offspring equally. We investigated food allocation and parent and chick behaviours in Magellanic penguins at their colony in Punta Tombo, Argentina, by observing feedings in one- and two-chick broods after the chicks were more than 20 days of age. Feeds lasted 21 min on average, and the length of a feed was not correlated either with the number of chicks in a brood, or with the amount of food the parents gave. Parents with two-chick broods distributed food evenly to both chicks. Although single chicks were fed more than chicks with siblings, as a proportion of a chick's start weight, both single chicks and lighter chicks in two-chick broods received significantly more food than heavier chicks. Chicks continued begging after the last feed in nearly half of the two-chick broods, suggesting they were not sated and so are food-limited. In linear mixed-effects models that considered, respectively, the absolute amount of food a chick received and the amount of food it received as a proportion of its start weight, chick begging was the most significant predictor of how much it was fed. Jostling behaviours between the chicks did not correlate with the amount of food either one received. Parental nonfeeding behaviours in two-chick broods (e.g. bending towards a chick and opening the bill but not regurgitating food) were more frequently directed at the lighter chick, but did not correlate with the amount of food a chick received. These results suggest (1) parents are motived to feed their chicks quickly, (2) parents try to allocate food equally to chicks of this age and (3) chicks devote most of their energy trying to get fed by the parent, rather than competing antagonistically with one another. Highlights • We observed parental and chick behaviour of Magellanic penguins during feeds. • Parents distributed food equally between heavier and lighter chicks >20 days old. • As a proportion of a chick's start weight, lighter chicks received more food. • A chick's begging was the most significant predictor of how much it was fed. • Chicks begged energetically for food but did not generally antagonize each other. [ABSTRACT FROM AUTHOR]

The Magellanic Penguin (Spheniscus magellanicus) is the most abundant and widely distributed seabird breeding on the Patagonian Coast of Argentina. We combined conventional stomach content and stable isotope analysis to assess Magellanic Penguin diet during the chick rearing stage at the two northernmost colonies in an area subject to fisheries. In 2011 and 2013, Thornfish (Bovichtus argentinus) was the main prey by mass at Complejo Islote Lobos (63.0% and 32.3%, respectively) and Argentine Anchovy (Engraulis anchoita) at Estancia San Lorenzo (85.2 and 63.3%, respectively). Magellanic Penguins from both colonies showed low isotopic niche overlap in 2011 (36%) and no overlap in 2013, suggesting a different use of prey species and/or foraging areas. Stable isotope mixing models showed that Argentine Anchovy (52.8%) and Thornfish (65.9%) were the main prey at Complejo Islote Lobos in 2011 and 2013, respectively, while Patagonian Redfish (Sebastes oculatus) (46.4%) and Squat Lobster (Munida gregaria) (50%) were the main prey at Estancia San Lorenzo in 2011 and 2013, respectively. Results show that in addition to Argentine Anchovy, previously recognized as main prey for breeding Magellanic Penguins in northern Patagonia, other juvenile or small sized fish are important diet items. Diet results suggest different scenarios of food conditions for each colony, despite the relative short distance between breeding locations. The low contribution of Argentine Hake (Merluccius hubbsi) and Argentine Shortfin Squid (Illex argentinus) suggests a low trophic overlap with commercial fisheries. The information provided is key to understand changes in the marine ecosystem and potential penguin-fishery interactions. [ABSTRACT FROM AUTHOR]

Aspergillosis is the main cause of mortality in captivity penguins. The infection occurs mainly by conidia inhalation of the Aspergillus genus, however, the fungus can also be dispersed by water. Therefore, this study aimed to evaluate water quality of the pool where the rehabilitated penguins remain at Centro de Recuperação de Animais Marinhos in Rio Grande city, Brazil, searching for the presence of the fungus Aspergillus spp. Water samples were collected weekly during a ten-month period and processed within six hours, applying the technique of filtrating membrane, with incubation at 25 ºC and 37 ºC during seven days. Of the forty samples analyzed, thirty-two were positive for the presence of Aspergillus genus, from these 60% correspond to A. fumigatus. Some variables significantly interfered on the isolation of Aspergillus genus and/or Aspergillus fumigatus specie, such as incubation temperature, seasonality and population density. This study showed Aspergillus spp. is present in the water, being one of the possible sources of infections for penguins in rehabilitation.

Abstract: This study aimed to evaluate the efficacy of detection of anti-Aspergillus fumigatus antibodies in captive penguins by double radial agar gel immunodiffusion (AGID) for the aspergillosis diagnosis. We included 134 Magellanic penguins (Spheniscus magellanicus) in rehabilitation at the Center for Recovery of Marine Animals (CRAM / FURG). All of them were monitored by AGID weekly until its final destination (death or release), totalizing 660 serum samples studied. All animals were clinically accompanied and post-mortem examinations was performed in penguins that died during the studied period. A total of 28% (37/134) of the penguins died, 89.2% (33/37) due to aspergillosis, 11% (4/37) by other causes and 97 were released. From the 33 animals with proven aspergillosis, 21 presented anti- A. fumigatus antibodies by AGID, being the average interval between death and positive AGID 16.4 days. Twelve animals with negative serology died of aspergillosis. The sensitivity and specificity rates were 63.6% and 95% respectively, and the positive and negative predictive values were 80.7% and 88.9% respectively. These data demonstrate that the serological monitoring for detection of antibodies by AGID can be an important tool for the diagnosis of aspergillosis in penguins.

Magellanic penguins (Spheniscus magellanicus) routinely migrate from their breeding colonies to Southern Brazil often contracting diseases during this migration, notably avian malaria, which has been already reported in Brazil and throughout the world. Detection of Plasmodium spp. in blood smears is the routine diagnostic method of avian malaria, however it has a low sensitivity rate when compared to molecular methods. Considering the negative impact of avian malaria on penguins, the aim of this study was to detect the presence of Plasmodium spp. in Magellanic penguins using Polymerase Chain Reaction (PCR) and by verifying clinical, hematological, and biochemical alterations in blood samples as well as to verify the likely prognosis in response to infection. Blood samples were obtained from 75 penguins to determine packed cell volume (PCV), red blood cell (RBC) and white blood cell (WBC) counts, mean corpuscular volume (MCV), uric acid, total protein, albumin, globulin and aspartate aminotransferase (AST) activity levels. Whole blood samples were used for PCR assays. Plasmodium spp. was detected in 32.0% of the specimens using PCR and in 29.3% using microscopic analyses. Anorexia, diarrhea and neurological disorders were more frequent in penguins with malaria and a significant weight difference between infected and non-infected penguins was detected. PCV and MCV rates showed no significant difference. RBC and WBC counts were lower in animals with avian malaria and leukopenia was present in some penguins. Basophil and lymphocyte counts were lower in infected penguins along with high monocyte counts. There was no significant difference in AST activities between infected and non-infected animals. There was a significant increase in uric acid values, however a decrease in albumin values was observed in infected penguins. Based on this study, we concluded that Plasmodium spp. occurs in Magellanic penguins of rehabilitation centers in Southeastern Brazil, compromising the weight of infected animals with clinical alterations appearing in severe cases of this disease. It was also noted that, although the hematological abnormalities presented by these animals may not have been conclusive, leukopenia, monocytosis and the decrease of basophils and lymphocytes revealed an unfavorable prognosis, and Plasmodium spp. infections may progress with elevated uric acid concentration and low albumin levels.

Abstract: Magellanic penguins (Spheniscus magellanicus) usually arrive in poor body conditions at Brazilian beaches during the winter. Hematology provides valuable information about clinical and immunity status of the animals. The aims of this study were to determine the hematologic, total plasma protein (TPP) and fibrinogen profiles of young and adult magellanic penguins in PROAMAR and CETAS-SC, relating these results with the state of health and survival possibility of the animals. In Paraná 14 animals were evaluated in pre and eight in post-rehabilitation and 29 animals were evaluated in Santa Catarina after rehabilitation. Before rehabilitation, all animals showed weakness. In hematological exams of these animals, we found that anemia was present in 83% of the penguins that died and 50% of those which survived. The heterophils/lymphocytes (H/L) ratio was 3.87±0.57 in animals that died, significantly higher than the average of 2.20±0.30 for animals that survived. These two parameters are useful to assess the survival possibility of animals to rehabilitation. The body condition score was positively correlated with hematocrit and TPP, and negatively correlated with H/L ratio. After rehabilitation, the values were similar to other animals of the family Spheniscidae, with averages ranging from 1.64 to 1.90x106 erythrocytes/μL; 43.38 to 48.80% of hematocrit; 12.45 to 13.52g/dL of hemoglobin; 8,684 to 14,011 leukocytes/μL; 4,767 to 8,041 heterophils/μL; 3,215 to 4,951 lymphocytes/μL; 95 to 655 eosinophils/μl; 179.8 to 277.9 monocytes/μL; 141 to 184.9 basophils/μL; and 1.26 to 1.74 of H/L ratio. These parameters can therefore be used as reference values and release parameters for young and adult Magellanic penguins in captivity on the rehabilitation centers.

Between 25–30 November 2013, 2014 and 2015, miniaturized video cameras were attached to Magellanic Penguins (Spheniscus magellanicus; n = 14) in Punta Norte/San Lorenzo, Península Valdés, Chubut, Argentina. The objective was to examine prey selection, consumption of untraceable prey, and inter- and intraspecific interactions. During 56.3 hr of video footage, 1,621 dives from 14 individuals were recorded. Magellanic Penguins swam through shoals of lobster krill (Munida gregaria morph subrugosa), selectively consuming the fish, primarily anchovies (Engraulis anchoita), that were dispersed along the shoal, but did not consume the lobster krill. Magellanic Penguins captured fish on dives of less than 2 m in depth. The tagged individuals foraged with conspecifics in 2% (n = 33) of the total recorded dives. In addition, a multispecies feeding association was also documented (n = 1). Results were constrained to the upper 40 m of the water column; below this depth light level was too low for detections by video. The development of cameras with a light source and wider-angle lens are crucial to improve our understanding of Magellanic Penguin foraging behavior. [ABSTRACT FROM AUTHOR]

The vulnerability of seabirds related to their migratory dynamics is frequently linked to environmental problems along the migration path. In this context, Magellanic penguins ( Sphenicus magellanicus ) seem to be vulnerable to an extensive range of environmental disturbances during their northward migration along the Atlantic waters of South America, which include by catch, marine debris ingestion, overfishing and environmental contamination. In this study, we investigate mercury accumulation in muscle and hepatic tissues of juveniles penguins collected along the Brazilian coast during three migratory seasonal years (2006, 2008 and 2012) and three areas along a latitudinal gradient. We found significant differences in Hg levels across the years, with higher hepatic Hg levels found in tissues of penguins sampled in 2008. The higher Hg levels in samples of penguins from 2008 might be attributed to variations in body condition or Hg uptake, associated with the trophic imbalance linked to an extreme El Niño event during that year. Significant differences in Hg accumulation across the latitudinal areas were also observed. The penguins sampled at the farthest area from the breeding ground presented the higher levels of Hg and also the poorest body condition. Body condition and other traits may influence the levels of chemical pollutants and decrease the migratory success rate in the juvenile age phase, compromising population dynamics. [ABSTRACT FROM AUTHOR]

We evaluate whether helminth parasites affect both cellular and humoral components of the immune system of Magellanic Penguin ( Spheniscus magellanicus (J.R. Forster, 1781)) chicks. We measured immune components after the administration of an antihelminthic drug to remove parasites. Cellular immune components included the complete white blood cell (WBC) count and the in vivo skin-swelling response to phytohemagglutinin (PHA). Humoral aspects assessed were the ability of plasma to agglutinate foreign particles and the bactericidal capacity of plasma. Antihelminthic treatment resulted in lower total WBC counts supporting the role of circulating leukocytes in fighting macroparasites. Deparasitized chicks showed a reduction in all types of leukocytes. Contrary to our expectation, deparasitized Magellanic Penguin chicks showed lower response to PHA injection than control chicks. The swelling response was positively correlated with body condition and with total WBC in circulation. We hypothesize that the specific helminth community naturally occurring in Magellanic Penguin chicks might have an overall immunostimulatory effect on the PHA response. Antihelminthic treatment did not alter the innate humoral immune parameters measured. Our results support the prediction that, given their relatively low costs of use and maintenance, innate humoral components would not be as affected by antihelminthic treatment as more costly cellular responses. [ABSTRACT FROM AUTHOR]

The Magellanic penguin ( Spheniscus magellanicus ) is a marine sentinel for the southern Atlantic Ocean that is a proxy of environmental quality. The presence of marine debris (macro-debris) in the stomach contents of emaciated juvenile penguins stranded from 21°S to 23°S was compared at different times (2000 and 2008), and the debris ingestion pathway was determined. The frequency of marine debris in the stomachs doubled in less than a decade, and flexible plastics remained the main ingested item over time (68–70%). The pelagic octopus, Argonauta nodosa , which inhabits the sea surface, was the most important prey species recovered in the stomach contents. The poor physical condition of the penguins that reach the northern migration limit (study area) reduces the diving capacity of the animals and increases their vulnerability to debris ingestion. Considering their preferred prey and physical condition, we conclude that the penguins likely ingested the marine debris in surface waters. [ABSTRACT FROM AUTHOR]

The occurrence of marine debris in the stomach contents of young male and female Spheniscus magellanicus stranded along the Atlantic coast of northern Argentina during its post-breeding exodus is reported for the first time. Marine debris was found in 15.5 % of 148 dead penguins, with a higher proportion of debris found in females when compared to males. A total of 81 debris items was recorded; plastic and paper each contributed with an equal number of debris whereas rubber contributed with a single item. Chemical identification performed using FTIR/ATR revealed that plastic items were largely LDPE and PA; other polymers included HDPE, PP and PS. The average length of fragmented plastic debris are in line with those reported from penguins stranded along the southern Brazilian coasts. Our study indicates that loads of ingested marine debris were roughly five times lower when compared to the estimates for the species in Brazilian beaches. • Only 23 penguins out of 148 had ingested debris (15.5 %). • A higher proportion of debris was found in females when compared to males. • Plastic and paper each contributed with an equal number of debris. • The average length of a flexible fragment of plastic was around 4 cm. • Using FTIR/ATR, plastic items found in stomachs were largely LDPE and PA. [ABSTRACT FROM AUTHOR]

We quantified the trophic niche of Magellanic penguins (Spheniscus magellanicus) breeding and moulting in Golfo San Jorge, Argentina, through conventional stomach content and stable isotope analysis. A total of 112 adults were flushed during the early and late chick stages of 2011 and 2012 at Isla Vernacci Norte, and at least 15 prey taxa were found, including fishes, cephalopods, crustaceans and polychaetes. Overall, Argentine anchovy (Engraulis anchoita) showed the highest contribution in terms of importance by mass (68.1–85.3%, depending on chick stage and year), except for the old chick stage in 2011 when the shortfin squid (Illex argentinus) was the main prey consumed (56.0%). Based on carbon and nitrogen isotopic values from a total of 256 blood samples, corresponding to young and old chicks and to adults of both sexes sampled throughout the incubation, chick and moult stages at the above mentioned colony and years, Bayesian mixing model outputs showed that Argentine anchovy was always the main prey (48–86%). Bayesian mixing model outputs obtained from adults of both sexes and their chicks during the late chick stage of 2013 at Isla Vernacci Norte, Isla Tova and Isla Leones also showed that Argentine anchovy was the main prey consumed. This is the first comprehensive assessment of Magellanic penguin diet composition in northern Patagonia, quantifying the relative contribution of prey in the diet of adults and chicks at different stages of the annual cycle and years, and confirms the relevance of a forage fish such as the Argentine anchovy in its trophic ecology. [ABSTRACT FROM PUBLISHER]

Fecundity, an important demographic variable for wildlife populations, is time consuming and expensive to measure. For seabirds, reproductive success is often estimated from 2 surveys of the colony, 1 during incubation and 1 during chick rearing. Using 33 yr of data on Magellanic Penguins [Spheniscus magellanicus), we compared reproductive success estimated from 2 surveys per season, from infrequent nest checks, and from daily nest checks to answer 4 questions; (1) Is reproductive success estimated from 2 surveys per season accurate enough for population models (within 15% of the 'true' value)? We found that the answer was yes, if surveys were done on optimal dates and chick counts were adjusted by the percentage of chicks that were heavy enough to fledge. Optimal dates depended on the synchrony and phenology of the species. If penguins bred particularly late or early in a given year, estimates were wrong even if counts were done on the average optimal date. (2) Can counts of occupied nests be adjusted based solely on date? We determined no, not without additional information on egg dates and egg and chick losses. (3) Can long-term trends in reproductive success be detected from 2 surveys per season? Our answer was yes; even using biased data from counts on suboptimal dates, trends with similar slopes were detected using both methods (2 surveys vs. nest checks). (4) How often must nests be checked to get reproductive success estimates comparable with those calculated from daily nest checks? We discovered that checking nests every 2 days was as good as doing daily checks. Reproductive success was overestimated by <5% when checks were conducted every 3-8 days and by <15% (in 90% of years) when checks were done every 9-30 days. The degree of overestimation depended on the timing of nest checks relative to egg laying, loss, and hatching. We conclude that reproductive success can be estimated from 2 surveys, but only if timing, synchrony, and variability of breeding are also known. [ABSTRACT FROM AUTHOR]

Captive penguins are prone to pododermatitis (bumblefoot) lesions due to sedentary habits, changes in normal activity patterns, prolonged time on hard and abrasive surfaces, and less time swimming in the water. Environmental enrichment allows the use of creative and ingenious techniques that aim to keep the captive animals occupied by increasing the range and the diversity of behavioral opportunities always respecting the ethological needs of the species. The main goal of this work was to use environmental enrichment techniques to reduce pododermatitis in a group of captive penguins. Five captive Magellanic penguins (Spheniscus magellanicus) that were showing bumblefoot lesions were followed during this project. To monitor the lesions, all animals were physically restraint 3 times a week over a period of 12 weeks. Environmental enrichment was introduced daily in the water with the goal of enhancing their time in the water for one extra hour daily. The results demonstrate that in a twelve weeks period, four animals showed significant reduction of the lesions in both feet and in two animals the lesions were completely healed. With these results we can conclude that aquatic environmental enrichment allowed this group of penguins to spend more time in the water, favoring the reduction of the bumblefoot lesions.