Explore the vast range of titles available.

We studied the migration of Magellanic penguins near the southern tip of the breeding distribution, and for the first time found evidence of partial migration for this species within the same colony. Forty‐three percent of the penguins studied stayed within ~ 290 km of the colony (residents), while others went northwards as far as 2000 km. All penguins spent the same amount of time at sea and traveled similar total distances, but residents experienced colder waters (2°C lower) and habitats with lower Chlorophyll‐a concentrations than migrants. The two habitats are inhabited by different prey items, consequently offering the penguins distinct prey options. We have shown high variability in the non‐breeding dispersion behavior of Magellanic penguins within the same colony; nonetheless, further research is required to understand the proximate and ultimate causes, and the consequences, of this behavior.

The proportions of individuals in various age classes in a population of wild animals affect population trends, behaviors, learning, and social structures. Knowledge of age structure is needed for effective conservation and management of populations. However, it is not always possible to determine the age or age class of individual animals, and hence the age structure of the population. Penguins, like most birds, cannot be aged once they molt into adult plumage. Spheniscus penguins attain adult plumage at 6 to 24 months of age, and individuals can live more than 30 years. We studied foot darkening in the four species of Spheniscus penguins to determine if age class can be determined from foot color. We compared how foot color changes with age among the four species to investigate potential functions of the darkening. We found that Spheniscus penguins have pale feet at hatching and the feet become darker with age throughout the lives of individuals. We showed that we can accurately predict the age structure of a colony of Magellanic penguins Spheniscus magellanicus , but not the ages of individual penguins, based on a sample of foot colors. The timing of foot darkening within species was consistent with foot color functioning in protection from UV radiation, and not with foot color functioning in thermoregulation. The species that breeds at the lowest latitudes and experiences the highest UV radiation (Galápagos penguins Spheniscus mendiculus ) had feet that darkened at the earliest ages, and the species that breed at higher latitudes and experience less intense insolation (African S. demersus and Magellanic penguins) had feet that darkened latest. Humboldt penguins S. humboldti breed mostly at low latitudes and foot darkening was intermediate between Galápagos and Magellanic penguins. We also found that males’ feet darken somewhat earlier than females’ feet, likely because females spend more time in their nests (burrows or under vegetation) than males and have less sun exposure. We found that feet darkened in an individual over years, but not within a breeding season. The color change is a life-long process, likely an evolutionary adaptation within species, not a seasonal, temporary response to UV radiation. We propose foot darkening as a way to assess age structure in Spheniscus penguins. Foot color in a colony of Magellanic penguins can provide a rapid, noninvasive method to estimate the age structure of the colony.

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.

More than half of the world's 18 penguin species are declining. We, the Steering Committeeof the International Union for Conservation of Nature Species Survival Commission PenguinSpecialist Group, voted on the penguin species in most critical need of conservation action.Because of their small or rapidly declining populations, the top three species identified in thisprocess were the African penguin (Spheniscus demersus), Galápagos penguin (Spheniscusmendiculus), and Yellow-eyed penguin (Megadyptes antipodes). To persist, these speciesrequire immediate scientific collaboration and policy intervention. In addition to highlightingthe three priority species, we used a pairwise ranking approach to prioritize research andconservation needs for all penguins. Among the 12 cross-taxa research areas we identified,we ranked quantifying population trends, estimating demographic rates, forecastingenvironmental patterns of change, and improving knowledge of fisheries interactions as thehighest priorities. The highest ranked conservation needs were to enhance marine spatialplanning, improve stakeholder engagement, and develop disaster management and speciesspecificaction plans. As part of our discussions, we identified four avenues for improvingtranslation of science into effective conservation for penguins. First, the scientific communityand funding bodies must recognize the importance of and support long-term research.Second, research on and conservation of penguins must expand its focus to include the nonbreedingseason and the juvenile stage. Third, marine reserves must be designed atecologically appropriate spatial and temporal scales. Lastly, communication betweenscientists and decision makers must be improved with the help of individual scientists,interdisciplinary species-specific working groups, and international working groups.

The process of hybridization between closely related species plays an important role in defining the genetic integrity and overall genetic diversity of species. The distribution range of Magellanic (Spheniscus magellanicus) and Humboldt (Spheniscus humboldti) penguins is predominantly allopatric; however, the species share a region of sympatry where they may hybridize. We analyzed four types of genetic markers (including nuclear and mitochondrial markers) to assess their utility in detecting hybridization events between Magellanic and Humboldt penguins. Genetic assessment of non-introgressed reference samples allowed us to identify three types of informative markers (microsatellites, major histocompatibility complex, and mitochondrial DNA) and detect positive evidence of introgressive hybridization in the wild. Four out of six putative hybrids showed positive evidence of hybridization, revealed by the detection of Humboldt mitochondrial DNA and Magellanic species-specific alleles from nuclear markers. Bayesian Structure analysis, including samples from the sympatric region of the species in the southern Pacific Ocean, confirmed the use of nuclear markers for detecting hybridization and genetic admixture of putative hybrids, but revealed relatively low levels of genetic introgression at the population level. These findings provide insights into the role of hybridization in regions of species sympatry and its potential consequences on the levels of genetic introgression, genetic diversity, and conservation of these penguin species.

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.

Haemosporidian parasites in the genus Plasmodium were recently detected through molecular screening in the Galapagos Penguin (Spheniscus mendiculus). We summarized results of an archipelagowide screen of 3726 endemic birds representing 22 species for Plasmodium spp. through a combination of molecular and microscopy techniques. Three additional Plasmodium lineages were present in Galapagos. Lineage A-infected penguins, Yellow Warblers (Setophaga petechia aureola), and one Medium Ground Finch (Geospiza fortis) was detected at multiple sites in multiple years. The other 3 lineages were each detected at one site and at one time; apparently, they were transient infections of parasites not established on the archipelago. No gametocytes were found in blood smears of infected individuals; thus, endemic Galapagos birds may be dead-end hosts for these Plasmodium lineages. Determining when and how parasites and pathogens arrive in Galapagos is key to developing conservation strategies to prevent and mitigate the effects of introduced diseases. To assess the potential for Plasmodium parasites to arrive via migratory birds, we analyzed blood samples from 438 North American breeding Bobolinks (Dolichonyx oryzivorus), the only songbird that regularly migrates through Galapagos. Two of the ephemeral Plasmodium lineages (B and C) found in Galapagos birds matched parasite sequences from Bobolinks. Although this is not confirmation that Bobolinks are responsible for introducing these lineages, evidence points to higher potential arrival rates of avian pathogens than previously thought. Parásitos de la familia Haemosporidia, del género Plasmodium recientemente fueron detectados por medio de análisis moleculares en el pingüino de las Galápagos (Spheniscus mendiculus). Resumimos los resultados de un análisis, extendido a lo largo del archipiélago, de 3726 aves endémicas representando a 22 especies para Plasmodium spp. mediante la combinación de técnicas moleculares y de microscopía. Tres linajes adicionales de Plasmodium estuvieron presentes en las Galápagos. El linaje A infectó pingüinos, individuos Setophaga petechia aureola y a un individuo de Geospiza fortis en sitios múltiples y en varios años. Los otros 3 linajes fueron detectados cada uno en un sitio y en un tiempo específico; aparentemente, fueron infecciones transitorias de parásitos no establecidos en el archipiélago. No se encontraron gametocitos en los frotis de sangre de individuos infectados; por esto, las aves endémicas de las Galápagos pueden ser hospederos finales de estos linajes de Plasmodium. Determinar cuándo y cómo llegaron los parasitos y los patógenos a las Galápagos es clave para desarrollar estrategias de conservación para prevenir y mitigar los efectos de las enfermedades introducidas. Para evaluar el potencial de llegada de Plasmodium en aves migratorias, analizamos muestras de sangre de 438 Dolichonyx oryzivorus en época reproductiva. Esta ave es la única canora que migra regularmente a través de las Galápagos. Dos de los linajes efímeros de Plasmodium (B y C) que se hallaron en las aves de las Galápagos coincidieron con secuencias de parásitos del ave canora. Aunque esto no confirma que Dolichonyx oryzivorus sea responsable de introducer estos linajes, la evidencia apunta a un potencial más alto de tasas de llegada de patógenos aviares de lo que se pensaba previamente.

The identification of when, how and where animals feed is essential to estimate the amount of energy they obtain and to study the processes associated with prey search and consumption. We combined the use of animal-borne video cameras and accelerometers to characterise the body and head movements associated to four types of prey capture behaviours in the Magellanic Penguin (Spheniscus magellanicus). In addition, we evaluated how the K-Nearest Neighbour (K-NN) algorithm recognized these behaviours from acceleration data. Finally, we compared the total capture and the capture per unit time (CPUT) derived by identifying prey capture events using the K-NN algorithm to that derived by counting undulations in the dive profile (“wiggles”). During captures, body and head movements were highly variable in the tridimensional space. Energy expenditure (i.e., VeDBA values) during diving periods with prey captures was from three to four times higher than during controls diving periods (i.e., with no capture events). The K-NN classification resulted effective and showed accuracy scores above 90% when considering both head and body related features. In addition, when captures were estimated using the K-NN method, the CPUT was similar or higher to that estimated by counting wiggles. Our study contributes to the knowledge of the trophic ecology of this species and provides an alternative method for estimating prey consumption in the Magellanic Penguin and other diving seabirds.

In birds, possible explanations for a bias in brood sex ratio include differential cost of rearing nestlings of different sexes, and different parental fitness returns related to offspring sex. We studied brood sex ratio of Magellanic penguins, Spheniscus magellanicus, in Puerto Deseado for 3 years. Our objectives were to compare the growth curves and energetic costs of rearing nestlings of different sexes, and to evaluate the possible implications of environmental and parental condition in the establishment of a bias in the brood sex ratio. We also investigated the relationship between hatching order and sex, and its impact on brood survival. Asymptotic mass was 11.41% higher for males than for females. The energetic cost of feeding male nestlings was slightly higher than for feeding females, but the difference in energy requirements was only 2.6% of the total energy budget. During the 3 years, brood sex ratio was 0.53, and almost constant within years over the raising period, showing no sex allocation during feeding. Sea surface temperature, which is linked to higher prey abundance when colder, explained brood sex ratio at fledging. The sex ratio was male-biased during the coldest year. Parental body condition was not an important variable explaining brood sex ratio. There was no bias in nestling sex with respect to hatching order and nestling survival was not related to nestling sex. We conclude that, even though the cost of feeding male offspring is higher, it only involves a small fraction of total cost of raising nestlings and might not be responsible for an adaptive bias in the sex ratio of nestlings for this species. However, during good oceanic conditions, females might bias their brood sex ratio towards males, thereby potentially gaining an advantage by raising good-quality males.

Variation in the foraging niche and parental provisioning behaviors of breeding seabirds have the potential to affect population dynamics (e.g. foraging success, breeding productivity, and ultimately population size). We sampled blood plasma of family’ groups (females, males, and chicks) of Magellanic penguins (Spheniscus magellanicus) from Martillo Island, Argentina. We used stable isotope analyses on plasma samples to examine food provisioning, isotopic niche, trophic position, and diet composition of penguins between the early and late chick-rearing periods. We found clear differences in the isotopic niches of penguins between the two stages of the chick-rearing period related to shifts in foraging habitat and/or diet composition between stages. We found no evidence of individual consistency in isotopic niches or sex-specific selective provisioning by adults. In addition, we found high variability within family groups (accounting for 90% of the total isotopic variability). This study improves our understanding of the age, sex, individual, and breeding stage-specific trophic niches of Magellanic penguins, which may be helpful in projecting how they may respond to future environmental change (e.g., changes that affect prey availability).