Concept: Humboldt Penguin
The African Penguin (Spheniscus demersus) is a highly social and vocal seabird. However, currently available descriptions of the vocal repertoire of African Penguin are mostly limited to basic descriptions of calls. Here we provide, for the first time, a detailed description of the vocal behaviour of this species by collecting audio and video recordings from a large captive colony. We combine visual examinations of spectrograms with spectral and temporal acoustic analyses to determine vocal categories. Moreover, we used a principal component analysis, followed by signal classification with a discriminant function analysis, for statistical validation of the vocalisation types. In addition, we identified the behavioural contexts in which calls were uttered. The results show that four basic vocalisations can be found in the vocal repertoire of adult African Penguin, namely a contact call emitted by isolated birds, an agonistic call used in aggressive interactions, an ecstatic display song uttered by single birds, and a mutual display song vocalised by pairs, at their nests. Moreover, we identified two distinct vocalisations interpreted as begging calls by nesting chicks (begging peep) and unweaned juveniles (begging moan). Finally, we discussed the importance of specific acoustic parameters in classifying calls and the possible use of the source-filter theory of vocal production to study penguin vocalisations.
The African penguin is a nesting seabird endemic to southern Africa. In penguins of the genus Spheniscus vocalisations are important for social recognition. However, it is not clear which acoustic features of calls can encode individual identity information. We recorded contact calls and ecstatic display songs of 12 adult birds from a captive colony. For each vocalisation, we measured 31 spectral and temporal acoustic parameters related to both source and filter components of calls. For each parameter, we calculated the Potential of Individual Coding (PIC). The acoustic parameters showing PIC ≥ 1.1 were used to perform a stepwise cross-validated discriminant function analysis (DFA). The DFA correctly classified 66.1% of the contact calls and 62.5% of display songs to the correct individual. The DFA also resulted in the further selection of 10 acoustic features for contact calls and 9 for display songs that were important for vocal individuality. Our results suggest that studying the anatomical constraints that influence nesting penguin vocalisations from a source-filter perspective, can lead to a much better understanding of the acoustic cues of individuality contained in their calls. This approach could be further extended to study and understand vocal communication in other bird species.
Penguins are major consumers in the southern oceans although quantification of this has been problematic. One suggestion proposes the use of points of inflection in diving profiles (‘wiggles’) for this, a method that has been validated for the estimation of prey consumption by Magellanic penguins (Spheniscus magellanicus) by Simeone and Wilson (2003). Following them, we used wiggles from 31 depth logger-equipped Magellanic penguins foraging from four Patagonian colonies; Punta Norte (PN), Bahía Bustamente (BB), Puerto Deseado (PD) and Puerto San Julián (PSJ), all located in Argentina between 42-49° S, to estimate the prey captured and calculate the catch per unit time (CPUT) for birds foraging during the early chick-rearing period. Numbers of prey caught and CPUT were significantly different between colonies. Birds from PD caught the highest number of prey per foraging trip, with CPUT values of 68±19 prey per hour underwater (almost two times greater than for the three remaining colonies). We modeled consumption from these data and calculate that the world Magellanic penguin population consumes about 2 million tons of prey per year. Possible errors in this calculation are discussed. Despite this, the analysis of wiggles seems a powerful and simple tool to begin to quantify prey consumption by Magellanic penguins, allowing comparison between different breeding sites. The total number of wiggles and/or CPUT do not reflect, by themselves, the availability of food for each colony, as the number of prey consumed by foraging trip is strongly associated with the energy content and wet mass of each colony-specific ‘prey type’. Individuals consuming more profitable prey could be optimizing the time spent underwater, thereby optimizing the energy expenditure associated with the dives.
The Magellanic Penguin (Spheniscus magellanicus) is native to Argentina, Chile and the Falkland/Malvinas islands and is a regular winter migrant in Uruguayan and Brazilian coastal waters. The species is known to be susceptible to a variety of gastrointestinal nematodes, cestodes, trematodes and acanthocephalans, as well as renal trematodes and pulmonary nematodes. Schistosomes (Platyhelminthes, Trematoda, Schistosomatidae) and microfilariae (Nematoda, Secernentea, Onchocercidae) were histologically identified in Magellanic Penguins (Spheniscus magellanicus) that died while under care at rehabilitation centers in southern Brazil. Phylogenetic analysis of the COI gene, ITS-1 region, 5.8 S rRNA gene, ITS-2 region and 28S rRNA gene sequences of the schistosome revealed that it is closely related to, but distinct from a schistosome reported from the African Penguin (Spheniscus demersus). The schistosomes from Magellanic and African Penguins were grouped with Gigantobilharzia huronensis, Gigantobilharzia melanoidis and Dendritobilharzia pulvurenta; however, the lack of a clearly monophyletic origin precludes determining their genus. The incidental discovery of novel parasites during a study that did not specifically aim to investigate the occurrence of helminths underscores the value of histopathological examination as an exploratory diagnostic approach.
Humans are unable to survive low temperature environments without custom designed clothing and support systems. In contrast, certain penguin species inhabit extremely cold climates without losing substantial energy to self-heating (emperor penguins ambient temperature plummets to as low as -45°C). Penguins accomplish this task by relying on distinct anatomical, physiological and behavioral adaptations. One such adaptation is a blood vessel heat exchanger called the ‘Rete Tibiotarsale’ - an intermingled network of arteries and veins found in penguins' legs. The Rete existence results in blood occupying the foot expressing a lower average temperature and thus the penguin loosing less heat to the ground. This study examines the Rete significance for the species thermal endurance. The penguin anatomy (leg and main blood vessels) is reconstructed using data chiefly based on the Humboldt species. The resulting model is thermally analyzed using finite element (COMSOL) with the species environment used as boundary conditions. A human-like blood vessel configuration, scaled to the penguin’s dimensions, is used as a control for the study. Results indicate that the Rete existence facilitates upkeep of 25-65% of the species total metabolic energy production as compared with the human-like configuration; thus making the Rete probably crucial for penguin thermal endurance. Here, we quantitatively link for the first time the function and structure of this remarkable physiological phenotype.
For all species, finite metabolic resources must be allocated toward three competing systems: maintenance, reproduction, and growth. Telomeres, the nucleoprotein tips of chromosomes, which shorten with age in most species, are correlated with increased survival. Chick growth is energetically costly and is associated with telomere shortening in most species. To assess the change in telomeres in penguin chicks, we quantified change in telomere length of wild known-age Magellanic penguin (Spheniscus magellanicus) chicks every 15 days during the species' growth period, from hatching to 60 days-of-age. Magellanic penguins continue to grow after fledging so we also sampled a set of 1-year-old juvenile penguins, and adults aged 5 years. Telomeres were significantly shorter on day 15 than on hatch day but returned to their initial length by 30 days old and remained at that length through 60 days of age. The length of telomeres of newly hatched chicks, chicks aged 30, 45 and 60 days, juveniles, and adults aged 5 years were similar. Chicks that fledged and those that died had similar telomere lengths. We show that while telomeres shorten during growth, Magellanic penguins elongate telomeres to their length at hatch, which may increase adult life span and reproductive opportunities.
A novel avian alphaherpesvirus, preliminarily designated as sphenicid alphaherpesvirus 1 (SpAHV-1) has been independently isolated from juvenile Humboldt and African penguins (Spheniscus humboldti and S. demersus) kept in German zoos suffering from diphtheroid oropharyngitis / laryngotracheitis and necrotizing enteritis (collectively designated as penguin-diphtheria-like disease). High-throughput sequencing was used to determine the complete genome sequences of the first two SpAHV-1 isolates. SpAHV-1 comprises a class D genome with a length of about 164 kbp, a G+C content of 45.6% and encodes 86 predicted ORFs. Taxonomic association of SpAHV-1 to the genus Mardivirus was supported by gene content clustering and phylogenetic analysis of herpesvirus core genes. The presented results imply that SpAHV-1 could be the primary causative agent of penguin-diphtheria-like fatal diseases in banded penguins. These results may serve as basis for the development of diagnostic tools, in order to investigate similar cases of penguin diphtheria in wild and captive penguins.
The major histocompatibility complex locus (MHC) is a gene region related to immune response and exhibits a remarkably great diversity. We deduced that polymorphisms in MHC genes would help to solve several issues on penguins, including classification, phylogenetic relationship, and conservation. This study aimed to elucidate the structure and diversity of the so far unknown MHC class I gene in a penguin species. The structure of an MHC class I gene from the Humboldt penguin (Spheniscus humboldti) was determined by using an inverse PCR method. We designed PCR primers to directly determine nucleotide sequences of PCR products from the MHC class I gene and to obtain recombinant clones for investigating the diversity of the MHC class I gene in Humboldt penguins. A total of 24 MHC class I allele sequences were obtained from 40 individuals. Polymorphisms were mainly found in exons 2 and 3, as expected from the nature of MHC class I genes in vertebrate species including birds and mammals. Phylogenetic analyses of MHC class I alleles have revealed that the Humboldt penguin is closely related to the Red Knot (Calidris canutus) belonging to Charadriiformes.
The use of stable isotopes for ecological studies has increased exponentially in recent years. Isotopic trophic studies are based on the assumption that animals are what they eat plus a discrimination factor. The discrimination factor is affected by many variables and can be determined empirically. The Magellanic penguin is a highly abundant marine bird that plays a key role in the southern oceans. This study provides the first estimation of the Magellanic penguin blood discrimination factor for (13) C and (15) N.
Multi-zoo comparisons of animal welfare are rare, and yet vital for ensuring continued improvement of zoo enclosures and husbandry. Methods are not standardized for the development of zoo enclosures based on multiple indicators, and case study species are required. This study compares behavior and breeding success to various enclosure and husbandry parameters for the Humboldt penguin, Spheniscus humboldti, for the development of improved enclosure design. Behavioral sampling was completed at Flamingo Land over a period of 8 months. Further data on behavior, enclosure design, and breeding success were collected via questionnaires, visits to zoos, and literature review. Breeding success was primarily influenced by colony age and number of breeding pairs, suggesting an important social influence on reproduction. Across zoos, there was also significant variation in behavior. The proportion of time spent in water varied between zoos (2-23%) and was used as an indicator of physical activity and natural behavior. Regression models revealed that water-use was best predicted by total enclosure area per penguin, followed by land area, with some evidence for positive influence of pool surface area per penguin. Predominantly linear/curvilinear increases in our biological indicators with enclosure parameters suggest that optimal conditions for S. humboldti were not met among the selected zoos. We propose revised minimum conditions for S. humboldti enclosure design, which exceed those in the existing husbandry guidelines. We present a framework for the evaluation of zoo enclosures and suggest that a rigorous scientific protocol be established for the design of new enclosures, based on multivariate methods. Zoo Biol. XX:XX-XX, 2016. © 2016 Wiley Periodicals, Inc.