Punta Tombo Research Articles

A fearful scourge to the penguin colonies: Southern giant petrel (Macronectes giganteus) predation on living Magellanic penguins (Spheniscus magellanicus) may be more common than assumed.

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.

Sex-specific migratory behavior in a marine predator results in higher risks to females

Protecting migratory species requires knowledge of their distributions throughout the year. Spatial or temporal segregation of females and males during part of the annual cycle complicates conservation measures and can lead to sex-biased mortality. Females and males of many seabird species use separate areas during the nonbreeding season, and sex-biased bycatch in fisheries is common. We satellite-tracked 8 female and 8 male post-breeding adult Magellanic penguins Spheniscus magellanicus, including 7 pairs, from Punta Tombo, Argentina, during their fall northbound migration. Our results agreed with recent studies from other colonies, and provided more accurate locations than the geolocator tags used in those studies. Females stayed 47 km closer to shore than males. On average, females and males reached similar latitudes from northern Argentina to southern Brazil. Females tended to stay farther north, however, with some males heading south by June. Body size did not influence how far offshore a penguin migrated, when controlling for sex. On average, females left the colony 2 d before their mates, and did not encounter them at sea. The mean distance between mates at sea was more than 350 km. Females are likely exposed to fishing gear and pollution more than males because the females stayed closer to shore and stayed farther north than males. Migratory routes varied among individuals. The large area that penguins use during their nonbreeding season makes protection of the population difficult.

Unprecedented heat mortality of Magellanic Penguins

AbstractExtreme 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.

Consequences of phenological shifts and a compressed breeding period in Magellanic penguins.

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 34yr 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 0.29d 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.

Geographical differences in sex-specific foraging behaviour and diet during the breeding season in the opportunistic Kelp Gull (Larus dominicanus)

Sexual segregation in feeding strategies has been widely reported in seabirds. Most seabirds occupy wide breeding distributional ranges, and dissimilar ecological settings may result in distinct environmental pressures on males and females leading to geographical differences in sexual segregation. Using GPS loggers and stable isotope analysis of whole blood (δ15N, δ13C), we assessed the occurrence of sexual differences in Kelp Gull (Larus dominicanus) foraging trip parameters, habitat use, isotopic niche and diet during the incubation period at three breeding locations in Argentina characterized by different foraging contexts. At Islote Arroyo Jabali Este, sexual differences were found in trip parameters and habitat use mainly associated with a significantly higher use by males of a refuse dump as foraging site. However, their isotopic niches were similar with both sexes consuming mostly recreational fish waste, suggesting it was mainly obtained by males at the dump and by females at shoreline areas used by fishers. At Punta Tombo, there were no sex differences in trip parameters nor in the main prey consumed consisting of fishery discards, although females used more shoreline areas and males presented a significantly larger isotopic niche width. In contrast, at Isla Vernaci Este, males and females showed similar trip parameters, habitat use, and isotopic niche width and diet composition. Results show geographical differences in the degree of sexual segregation, which may result from differences in the availability of local food resources, particularly anthropogenic food subsidies.

Lateralization (handedness) in Magellanic penguins.

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.

Food allocation and feeding behaviours of Magellanic penguin, Spheniscus magellanicus, adults and chicks

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.

Sex-biased survival contributes to population decline in a long-lived seabird, the Magellanic Penguin.

We developed a Hidden Markov mark–recapture model (R package marked) to examine sex‐specific demography in Magellanic Penguins (Spheniscus magellanicus). Our model was based on 33 yr of resightings at Punta Tombo, Argentina, where we banded ~44,000 chicks from 1983 to 2010. Because we sexed only 57% of individuals over their lifetime, we treated sex as an uncertain state in our model. Our goals were to provide insight into the population dynamics of this declining colony, to inform conservation of this species, and to highlight the importance of considering sex‐specific vital rates in demographic seabird studies. Like many other seabirds, Magellanic Penguins are long‐lived, serially monogamous, and exhibit obligate biparental care. We found that the non‐breeding‐season survival of females was lower than that of males and that the magnitude of this bias was highest for juveniles. Biases in survival accumulated as cohorts aged, leading to increasingly skewed sex ratios. The survival bias was greatest in years when overall survival was low, that is, females fared disproportionality worse when conditions were unfavorable. Our model‐estimated survival patterns are consistent with independent data on carcasses from the species’ non‐breeding grounds, showing that mortality is higher for juveniles than for adults and higher for females than for males. Juveniles may be less efficient foragers than adults are and, because of their smaller size, females may show less resilience to food scarcity than males. We used perturbation analysis of a population matrix model to determine the impact of sex‐biased survival on adult sex ratio and population growth rate at Punta Tombo. We found that adult sex ratio and population growth rate have the greatest proportional response, that is, elasticity, to female pre‐breeder and adult survival. Sex bias in juvenile survival (i.e., lower survival of females) made the greatest contribution to population declines from 1990 to 2009. Because starvation is a leading cause of morality in juveniles and adults, precautionary fisheries and spatial management in the region could help to slow population decline. Our data add to growing evidence that knowledge of sex‐specific demography and sex ratios are necessary for accurate assessment of seabird population trends.

Oceanographic conditions in wintering grounds affect arrival date and body condition in breeding female Magellanic 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 601:253-267 (2018) - DOI: https://doi.org/10.3354/meps12668 Oceanographic conditions in wintering grounds affect arrival date and body condition in breeding female Magellanic penguins Ginger A. Rebstock*, P. Dee Boersma Center for Ecosystem Sentinels, Department of Biology, University of Washington, Seattle, WA 98195-1800, USA *Corresponding author: gar@uw.edu ABSTRACT: Overwintering conditions often impact an individual animal’s breeding performance in the following season. These so-called carry-over effects have been demonstrated in birds, including penguins. We studied carry-over effects in Magellanic penguins Spheniscus magellanicus, a species of conservation concern, breeding at Punta Tombo, Argentina, and wintering from northern Argentina to southern Brazil. We characterized oceanographic conditions in the penguins’ wintering grounds from 1982 to 2012 using principal component analysis on weekly sea surface temperature (SST) anomalies. The first principal component represented a weak Rio de la Plata plume and warm SST. The Rio de la Plata plume carries cool, productive, low-salinity water north from the river mouth through the penguins’ wintering area. The plume is stronger (extends farther north) when winds blow from the southwest than when winds blow from the northeast. When the Rio de la Plata plume was weak in late winter, females arrived earlier to breed and were in better condition, likely because prey was concentrated in a smaller plume area closer to Punta Tombo. Females that arrived earlier laid eggs earlier, and females laid larger eggs when they arrived earlier and were in better condition. In contrast, body condition of breeding males did not vary with winter conditions. The effects on individual females varied, likely reflecting in part individual foraging ability. A weaker Rio de la Plata plume probably increased prey encounter rates closer to breeding colonies in winter, directly and indirectly improving female body condition, increasing egg size, and resulting in earlier arrival and egg laying. KEY WORDS: Carry-over effect · Spheniscus magellanicus · Magellanic penguin · Arrival date · Body condition · Egg-laying date · Egg size Full text in pdf format PreviousNextCite this article as: Rebstock GA, Boersma PD (2018) Oceanographic conditions in wintering grounds affect arrival date and body condition in breeding female Magellanic penguins. Mar Ecol Prog Ser 601:253-267. https://doi.org/10.3354/meps12668 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 601. Online publication date: August 09, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.

Ecotourism effects on health and immunity of Magellanic penguins at two reproductive colonies with disparate touristic regimes and population trends.

Negative effects of ecotourism on wildlife are rising worldwide. Conservation physiology can play a major role in protecting wildlife by providing early alerts on changes in the status of individuals exposed to tourist activities. We measured an integrated set of immune and health-state indices to evaluate the effects of ecotourism on Magellanic penguins (Spheniscus magellanicus). We studied two reproductive colonies that differed in the intensity of tourism and population trends: Punta Tombo (higher tourism intensity, declining population) and San Lorenzo (lower tourism intensity, growing population). Within each colony, we compared individuals from an area that was exposed to tourists and a control area where tourism was excluded. Adult penguins exposed to tourism at Punta Tombo, but not at San Lorenzo, showed physiological alterations indicative of chronic stress (higher heterophil to lymphocyte ratios) and parasitic infection (elevated heterophil and eosinophil counts). Penguin chicks exposed to tourism at Punta Tombo, but not at San Lorenzo, also showed physiological alterations indicative of poor immune and general-health condition: lower humoral innate immunity, haematocrit, and glucose levels and higher inflammatory responses likely due to increased prevalence of fleas. Our results indicate that individuals of a declining population exposed to high levels of tourism express physiological indicators of chronic stress and poor health that could make adults and juveniles vulnerable to disease. These effects are expressed despite a long history of exposure and behavioural habituation to human visitation. In contrast, individuals of a growing population exposed to more recent and lower levels of tourism showed no effect. Our study demonstrates how a diverse physiological toolkit within a conservation physiology approach can provide important information for a better comprehension of anthropogenic effects on wild animals in our changing world.

Natural selection on morphology varies among years and by sex in Magellanic Penguins (Spheniscus magellanicus)

ABSTRACT The evolution of morphology in a population reflects several factors, including the influence of environmental variability on natural selection. We estimated natural selection on, and heritability of, 4 individual morphological traits (bill length, bill depth, flipper length, and foot length) and 2 multivariate morphological traits in adult Magellanic Penguins (Spheniscus magellanicus) at Punta Tombo, Argentina, from 1983 to 2010. We estimated heritability of morphology with parent–offspring regression and animal models, conditioning on sex because the species is sexually dimorphic. For the analysis of selection on each trait, we estimated both linear and quadratic selection gradients, based on the number of fledglings produced, for breeding males and females in each year. Estimates from animal models indicated that all 6 traits were heritable; in parent–offspring regressions, corresponding heritabilities were significantly higher in sons than in daughters in 100% of tests. Over 28 yr, we detecte...

The importance of variation

Evolution![Figure][1] Magellanic penguins in Punto Tombo, Argentina PHOTO: DON FAULKNER/FLICKR The environment exerts powerful selective forces on species, shaping their morphology. Despite this, individuals within a species can be quite variable, suggesting that selection may not always operate in expected ways. Koehn et al. measured selection in Magellanic penguins at Punta Tombo, Argentina, over nearly 30 years. Though this extreme environment would seem to impose powerful selective forces, they found evidence of selection at a suite of traits in only 7 of those years. When selection was detected, primarily for body size, it favored larger individuals. Such inconsistency in the strength and shape of selection over time likely maintains important variation within the population overall and suggests that there is no clear best-adapted morphology in this dynamic habitat. Auk 10.1642/AUK-16-50.1 (2016). [1]: pending:yes

GENETICS AND DEMOGRAPHY OF KELP GULLS IN PATAGONIA

The Kelp Gull (Larus dominicanus), a common seabird in coastal Patagonia, has recently increased in overall abundance and distribution, creating some concerns for the protection and conservation of other native, threatened species. We combined genetic and demographic data of four large Kelp Gull colonies distributed along 1800 km of the northern Patagonian coast of Argentina to further understand patterns of population growth and migration of the species. DNA analysis of variable intron sequences of two separate genes (myelin proteolipid protein, β-fibrinogen) revealed similar intra-colony levels of DNA sequence diversity. Pairwise FST comparisons revealed significant differentiation of the northernmost colony, Islote La Pastosa, from the two southern colonies, Punta Tombo and Isla Vernaci Sudoeste (p &lt; 0.05). Indirect estimates of gene flow suggest significant mixing among colonies (Nm &gt; 6). Demographic estimates revealed that Islote La Pastosa showed an increase in the number of breeding individuals over time (λ = 1.075), representing an area of potential population expansion. This is consistent with previous studies that have suggested that the demographic connectivity among Kelp Gull colonies in Patagonia may follow a source-sink dynamics, where growth rates of growing colonies are fuelled by the immigration of individuals from nearby colonies. The observed pattern also reflects the overall expansion of the species in the Patagonian region. This study suggests that proper management strategies for the Kelp Gull should take into account the genetic and demographic dynamics of this species.

Marine protection is needed for Magellanic penguins in Argentina based on long-term data

Magellanic penguins (Spheniscus magellanicus) are listed as near threatened by the IUCN. At their largest colony, Punta Tombo, Chubut, Argentina, active nests declined >30% over 30years. Reproductive success is low, many penguins forage far from the colony, and starvation, the major cause of chick death, kills 39% of chicks on average each year. A 210-ha provincial reserve protects part of the breeding colony but there is no marine protected area (MPA) around Punta Tombo. An MPA protecting the foraging area of adults with small chicks could reduce chick starvation, increase reproductive success, and reduce adult mortality. The Province of Chubut wants an MPA to protect penguins at Punta Tombo but when and where would an MPA be most effective? We used our long-term dataset to determine that most chicks starve within 20–30days after hatching (November and December).We used satellite tags to track penguins foraging for chicks <20days of age in 1997–2001 and 2006–2009. Core foraging areas for penguins whose chicks did not starve (successful) and those whose chicks starved (unsuccessful) partially overlapped. Unsuccessful penguins, however, foraged farther from the colony (59±27km, N=39 penguins, 115 trips) and had a larger core foraging area (554 km2) than successful penguins (46±19km, N=23 penguins, 78 trips, P=0.002; 375km2). Unsuccessful parents took longer to return to feed their chicks, increasing chick starvation. There is a limited window of opportunity to secure protection through adequate management of a critical foraging area for penguins and the rich assemblage of other marine species using the same area. Increases in chick growth and survival would demonstrate the effectiveness of the MPA.

Pollution, habitat loss, fishing, and climate change as critical threats to penguins.

Cumulative human impacts across the world's oceans are considerable. We therefore examined a single model taxonomic group, the penguins (Spheniscidae), to explore how marine species and communities might be at risk of decline or extinction in the southern hemisphere. We sought to determine the most important threats to penguins and to suggest means to mitigate these threats. Our review has relevance to other taxonomic groups in the southern hemisphere and in northern latitudes, where human impacts are greater. Our review was based on an expert assessment and literature review of all 18 penguin species; 49 scientists contributed to the process. For each penguin species, we considered their range and distribution, population trends, and main anthropogenic threats over the past approximately 250 years. These threats were harvesting adults for oil, skin, and feathers and as bait for crab and rock lobster fisheries; harvesting of eggs; terrestrial habitat degradation; marine pollution; fisheries bycatch and resource competition; environmental variability and climate change; and toxic algal poisoning and disease. Habitat loss, pollution, and fishing, all factors humans can readily mitigate, remain the primary threats for penguin species. Their future resilience to further climate change impacts will almost certainly depend on addressing current threats to existing habitat degradation on land and at sea. We suggest protection of breeding habitat, linked to the designation of appropriately scaled marine reserves, including in the High Seas, will be critical for the future conservation of penguins. However, large-scale conservation zones are not always practical or politically feasible and other ecosystem-based management methods that include spatial zoning, bycatch mitigation, and robust harvest control must be developed to maintain marine biodiversity and ensure that ecosystem functioning is maintained across a variety of scales.

Climate Change Increases Reproductive Failure in Magellanic Penguins

Climate change is causing more frequent and intense storms, and climate models predict this trend will continue, potentially affecting wildlife populations. Since 1960 the number of days with >20 mm of rain increased near Punta Tombo, Argentina. Between 1983 and 2010 we followed 3496 known-age Magellanic penguin (Spheniscus magellanicus) chicks at Punta Tombo to determine how weather impacted their survival. In two years, rain was the most common cause of death killing 50% and 43% of chicks. In 26 years starvation killed the most chicks. Starvation and predation were present in all years. Chicks died in storms in 13 of 28 years and in 16 of 233 storms. Storm mortality was additive; there was no relationship between the number of chicks killed in storms and the numbers that starved (P = 0.75) or that were eaten (P = 0.39). However, when more chicks died in storms, fewer chicks fledged (P = 0.05, R 2 = 0.14). More chicks died when rainfall was higher and air temperature lower. Most chicks died from storms when they were 9–23 days old; the oldest chick killed in a storm was 41 days old. Storms with heavier rainfall killed older chicks as well as more chicks. Chicks up to 70 days old were killed by heat. Burrow nests mitigated storm mortality (N = 1063). The age span of chicks in the colony at any given time increased because the synchrony of egg laying decreased since 1983, lengthening the time when chicks are vulnerable to storms. Climate change that increases the frequency and intensity of storms results in more reproductive failure of Magellanic penguins, a pattern likely to apply to many species breeding in the region. Climate variability has already lowered reproductive success of Magellanic penguins and is likely undermining the resilience of many other species.

Beach Attendance in Magellanic PenguinsSpheniscus magellanicus

Seabirds depend on a variety of terrestrial habitats during the part of their life cycle that they spend on land. Understanding the temporal patterns of use of these habitats provides insights into their ecological requirements, and ultimately helps to direct efforts that ensure the birds' protection. We investigated Magellanic penguin Spheniscus magellanicus beach attendance at Punta Tombo, Argentina, during three breeding seasons to understand the use of beach habitat by juveniles and adults in the breeding season, during the day and in response to physical stressors. We found that beaches at the breeding colony are actively used during the breeding season. The number of penguins on the beach increased as the breeding season progressed for both juveniles and adults, but their patterns of beach use differed. Juveniles arrived later in the season and their numbers on the beach reflected their moulting cycle. In all three years, juveniles left the beach in late January, consistent with their pre-moult foraging trip. Adult penguins, on the other hand, attended the beach in larger numbers during hot days, suggesting that breeders used the beach to avoid high inland temperatures. More penguins, both juveniles and adults, were on the beach during the afternoons, which probably reflects their foraging pattern. However, juvenile counts were less variable between mornings and afternoons than adult counts, indicating a more even use of the beach by juveniles. Beaches provide an alternative habitat for several key functions throughout the life cycle of Magellanic penguins but the birds' temporal patterns of attendance probably depend on their age and breeding status and on the ambient temperature. Our study highlights the importance of the beaches surrounding Magellanic penguin colonies and provides guidance for the spatial layout of reserves where penguin colonies occur.

Avian Pox in Magellanic Penguins (Spheniscus magellanicus)

Avian pox is an enveloped double-stranded DNA virus that is mechanically transmitted via arthropod vectors or mucosal membrane contact with infectious particles or birds. Magellanic Penguins (Spheniscus magellanicus) from two colonies (Punta Tombo and Cabo Dos Bahías) in Argentina showed sporadic, nonepidemic signs of avian pox during five and two of 29 breeding seasons (1982-2010), respectively. In Magellanic Penguins, avian pox expresses externally as wart-like lesions around the beak, flippers, cloaca, feet, and eyes. Fleas (Parapsyllus longicornis) are the most likely arthropod vectors at these colonies. Three chicks with cutaneous pox-like lesions were positive for Avipoxvirus and revealed phylogenetic proximity with an Avipoxvirus found in Black-browed Albatross (Thalassarche melanophrys) from the Falkland Islands in 1987. This proximity suggests a long-term circulation of seabird Avipoxviruses in the southwest Atlantic. Avian pox outbreaks in these colonies primarily affected chicks, often resulted in death, and were not associated with handling, rainfall, or temperature.

Mercury levels in feathers of Magellanic penguins

Feathers are useful to determine mercury (Hg) contamination. We evaluated the mercury concentration in feathers of Magellanic penguins (Spheniscus magellanicus) age 1.5years to 25years at Punta Tombo, Argentina before and during their molt. Mercury ranged between <1.4 and 367ng/gdryweight, with three extreme high values (8996ng/g, 3011ng/g and 1340ng/g) all in young adults. The median concentration was lowest for juveniles and significantly higher for adults but with high variation among older adults. Males and females had similar mercury loads. Compared with other penguin species, concentrations in Magellanic penguins were low. Mercury levels for Magellanic penguins in the Southwest Atlantic for older adults averaged 206±98ng/g, and serve as a baseline for biomonitoring and/or ecotoxicological studies.

Fishery Discards and Incidental Mortality of Seabirds Attending Coastal Shrimp Trawlers at Isla Escondida, Patagonia, Argentina

We evaluated seabird attendance and incidental mortality at coastal trawl vessels targeting Argentine red shrimp (Pleoticus muelleri) in the Isla Escondida fishing area, Argentina, during 2006–2007 and 2007–2008. Eight seabird species attended vessels, and the most frequent and abundant seabird (percent occurrence, mean number per haul) in the two seasons was the Kelp Gull (Larus dominicanus) (100%, 112.3 and 100%, 263.4, respectively), followed by the Black-browed Albatross (Thalassarche melanophris) (85%, 17.6, and 90%, 32.4, respectively). Eleven Magellanic Penguins (Spheniscus magellanicus) and one Imperial Shag (Leucocarbo atriceps) were killed in nets with a mean capture rate of 0.003 and 0.0003 birds per haul, respectively. The estimated total number of birds killed was 53 penguins and five shags considering the total number of hauls made by the fishery in the two seasons. No contacts between seabirds and warp cables were recorded. Coastal shrimp vessels generally operated between 15 and 20 km offshore, at a mean distance from the main Kelp Gull colony (Punta Tombo) of 43.9 km. At least 100 fish and invertebrate species were discarded, mostly Argentine hake (Merluccius hubbsi). Total amount discarded per season by this coastal fishery in the two seasons was estimated at 3,284 and 6,590 tonnes, respectively. The coastal shrimp fishery in the Isla Escondida area appears to have a small impact on seabirds in terms of incidental mortality but provides significant amounts of supplementary food during the breeding season of the Kelp Gull.