Peter Dann

Mortality and breeding failure of little penguins, Eudyptula minor, in Victoria, 1995–96, following a widespread mortality of pilchard, Sardinops sagax

In May 1995, numbers of little penguins, Eudyptula minor, coming ashore declined at Phillip Island and St Kilda concurrently with deaths of many penguins in western Victoria and a massive mortality of one of their food species (pilchard) throughout southern Australia. Among 1926 dead penguins reported were 131 banded birdsrecovered from Phillip Island (86% adults and 14% first-year birds), 26 from Rabbit Island and six from St Kilda. The number of banded penguins found dead per number of adult Phillip Island birds at risk was 2.3% in 1995 compared with an annual mean of 0.7% for 1970–93. Of 29 corpses autopsied, at least 26 died of starvation associated with mild–severe gastro-intestinal parasitism. Following the pilchard mortality, egg-laying by penguins in the subsequent breeding season (1995–96) was ~2 weeks later than the long-term mean and 0.3 chicks were fledged per pair compared with the long-term mean of 1.0. Unlike previous years, few penguins were recorded in Port Phillip Bay in September–October 1995, a period when pilchard schools were infrequently seen. It is concluded that the increase in penguin mortality in northern Bass Strait and the significant reduction in breeding success were associated with the widespread pilchard mortality.

Observed and predicted effects of climate on Australian seabirds

Abstract Although there is growing evidence of climate warming, for many regions the broader effects of climate variation on marine top predators remains unknown owing to the difficulty in obtaining, for synthesis, long-term and short-term datasets on multiple species. In the Australian region, climatic and oceanographic variability and change have been shown to affect marine species, often with profound consequences. Many seabirds are apex predators for which changes in climatic and oceanic dynamics have driven range movements poleward, reduced breeding success and altered breeding timing for some species. Here we review the literature to assess and determine the vulnerability of Australian seabirds to variation and change in climate and identify which species and ecosystems may be more resilient to future climate warming. It is clear from this synthesis that not all Australian seabirds are affected similarly, with responses varying by species and location. In addition, the paucity of information on the distribution and biology of seabird prey, foraging patterns and movements of seabirds, and the ability of seabirds to switch between prey species or adjust timing of life-cycles make generalisations about potential effects of future climate change and adaptive capacity in seabirds difficult. This applies both within Australia and elsewhere, where data are similarly sparse.

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

Cumulative human impacts across the worlds 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.

Interspecific variations in the gastrointestinal microbiota in penguins

Despite the enormous amount of data available on the importance of the gastrointestinal (GI) microbiota in vertebrate (especially mammals), information on the GI microbiota of seabirds remains incomplete. As with many seabirds, penguins have a unique digestive physiology that enables them to store large reserves of adipose tissue, protein, and lipids. This study used quantitative real‐time polymerase chain reaction (qPCR) and 16S rRNA gene pyrosequencing to characterize the interspecific variations of the GI microbiota of four penguin species: the king, gentoo, macaroni, and little penguin. The qPCR results indicated that there were significant differences in the abundance of the major phyla Firmicutes, Bacteroides, Actinobacteria, and Proteobacteria. A total of 132,340, 18,336, 6324, and 4826 near full‐length 16S rRNA gene sequences were amplified from fecal samples collected from king, gentoo, macaroni, and little penguins, respectively. A total of 13 phyla were identified with Firmicutes, Bacteroidetes, Proteobacteria, and Fusobacteria dominating the composition; however, there were major differences in the relative abundance of the phyla. In addition, this study documented the presence of known human pathogens, such as Campylobacter, Helicobacter, Prevotella, Veillonella, Erysipelotrichaceae, Neisseria, and Mycoplasma. However, their role in disease in penguins remains unknown. To our knowledge, this is the first study to provide an in‐depth investigation of the GI microbiota of penguins.

Determining the sex of Little Penguins (Eudyptula minor) in northern Bass Strait using morphometric measurements

Abstract In avian species with no obvious differences in plumage or body size between the sexes, such as penguins, discriminant function analysis (DFA) of morphometric measurements that display sexual dimorphism can provide a simple and rapid means of determining sex in the field. Like most other penguin species, the Little Penguin (Eudyptula minor) displays sexual dimorphism in bill shape and size. In the present study, discriminant functions (DFs) were developed for sexing adult Little Penguins at two colonies in northern Bass Strait, Victoria, Australia, and their accuracies were compared with those obtained previously in other parts of the species’ range. Backwards stepwise DFA indicated that birds at Phillip Island can be sexed with an accuracy of 91% using a single measurement of bill depth (>13.33 mm classed as males). Similar analyses at Gibson Steps produced a DF incorporating bill length, bill depth and head length [although the model with the greatest accuracy when applied to birds from Phillip Island (91%) also contained only bill depth]. Published DFs derived in New Zealand had accuracies of 50–85% when applied to birds from Phillip Island and Gibson Steps, supporting earlier suggestions that DFs are not applicable across subspecies of the Little Penguin. In contrast, there was little difference between the accuracy of the DFs in the present study and that previously derived for the same subspecies in Tasmania when applied to birds from Phillip Island (89%) and Gibson Steps (92%). However, as the degree of variation in bill size within a subspecies is unknown it may still be prudent to derive colony-specific DFs.

Movements and Patterns of Mortality at Sea of Little Penguins Eudyptula minor from Phillip Island, Victoria

Between 1967 and 1988, almost 16 000 young and adult Little Penguins were banded on Phillip Island; 413 of these have been recovered away from the Island. Most first-year and adult birds were recovered west (95.3% and 92.6% respectively) of the colony. Significant concentrations of first-year recoveries came from between Phillip Island and Cape Otway in Victoria and from between Warrnambool, Victoria, and Port MacDonnell, South Australia. Few birds have been recovered in their second year away from Phillip Island. The distributional pattern of recoveries of second-year birds was intermediate between that of the first-year birds and adults. Two noticeable differences between the distributions of adults and first-year birds were: the much greater importance of Port Phillip Bay for the older birds (64.8% of recoveries compared to 4.3%) and the less widespread range of adult recoveries. Most first-year mortality at sea occurred between summer and winter whereas adult mortality increased in autumn and early spring. Possible reasons for these differences are discussed.

MARK-RECAPTURE-RECOVERY MODELING AND AGE-RELATED SURVIVAL IN LITTLE PENGUINS (EUDYPTULA MINOR)

Abstract We analyzed yearly mark-recapture-recovery information collected over a 36-year period for the Little Penguins (Eudyptula minor) of Phillip Island in southeastern Australia. We show that it is feasible to model age-dependence for the survival, recapture, and recovery probabilities simultaneously, and that such a modeling scheme yields biologically realistic age structures for the model parameters. We provide illustrations of potentially erroneous results that may arise when researchers fail (1) to consider simultaneous age-dependence or (2) to detect annual variations that may mask age-dependence. From 1968 to 2004, 23,686 chicks were flipper-banded; 2,979 birds were encountered after fledging, and 1,347 were ultimately recovered dead. We found low survival of 17% in the first year of life, increasing to 71% in the second year of life, 78% in the third year, and 83% thereafter, and declining gradually after nine years of age. A population model allowing for immigration of birds from areas surrounding the study sites fits the observed stable population in the study sites. Modelado de Marca-Recaptura-Recuperación y Supervivencia Relacionada con la Edad en Eudyptula minor

Population regulation in Little Penguins (Eudyptula minor): the role of intraspecific competition for nesting sites and food during breeding

Abstract Although studies of seabirds have had a fundamental influence on development of theories of population regulation, the role and importance of potential factors regulating seabird populations remain unresolved. Food supply is commonly thought to be a significant limiting factor regulating seabird populations but difficulty in measuring availability of prey has meant that direct evidence is usually lacking. Here we examine the role that intraspecific competition for breeding sites and food during the breeding season plays in determining the size of populations of Little Penguins (Eudyptula minor) in south-eastern Australia. The relation between population sizes and available breeding area suggest that numbers of Little Penguins may be limited on smaller islands by area but clearly are not on larger islands. Little Penguins have very short foraging ranges and thus are likely to experience density-dependent food shortages when breeding. We found support for Ashmoles ‘halo effect’ in that there was an inverse relationship between colony size and mean mass of chicks near fledging. However, more recent variations of this model (e.g. the ‘hungry horde’, or ‘hinterland’) do not explain the observed distribution and numbers of penguins breeding in Victoria. We conclude that both factors may be involved in the regulation of Little Penguin populations locally, and propose a model in which the area available for nesting is combined with intraspecific competition for food during breeding as co-determinants of population size.

Range-Wide Phylogeography of the Little Penguin (Eudyptula minor): Evidence of Long-Distance Dispersal

ABSTRACT. The Little Penguin (Eudyptula minor), a colonial-nesting seabird that is widespread in New Zealand and southern Australia, has high dispersal potential but exhibits regional variation in morphology, coloration, and breeding phenology. We present a distribution-wide survey of mitochondrial DNA variation in the Little Penguin to document phylogeographic relationships and genetic structuring and to test for concordance with intraspecific taxonomy. Phylogeographic structuring was absent among Australian colonies (27 localities, 94 individuals), but the distribution of haplotypes among colonies was significantly nonrandom (ϕST = 0.110, P < 0.01). The Australian individuals exhibited close phylogenetic relationships with a subset of New Zealand birds (4 localities, 22 individuals), whereas the remaining New Zealand birds (20 localities, 106 individuals) were phylogenetically distinct, with ≥7% sequence divergence, and exhibited greater levels of genetic variation and geographic structuring (ϕST = 0.774, P < 0.05). These patterns are consistent with earlier suggestions of an origin in New Zealand followed by recent colonization of Australia and back-dispersal to New Zealand. Extinction and re-establishment processes may have been important factors in the development of genetic structuring across a range of spatiotemporal scales. The genetic data are consistent with suggestions that a single subspecies exists in Australia, but not with the subspecies distributions within New Zealand that have been suggested on the basis of morphology and coloration. RESUMEN. El pingüino Eudyptula minor es un ave marina que anida en colonias y que se distribuye ampliamente en Nueva Zelanda y en el sur de Australia. Esta especie presenta un alto potencial de dispersión pero presenta variación regional en su morfología, coloración y fenología reproductiva. Presentames un muestreo de la variación del ADN mitocondrial que abarca toda el área de distribución de esta especie para documentar sus relaciones filogeográficas y estructuración genética y también para probar la concordancia con la taxonomía intraespecífica. No existió estructuración filogeográfica entre las colonias australianas (27 localidades, 94 individuos), pero la distribución de los haplotipos entre las colonias fue significativamente diferente a la esperada por azar (ϕST = 0.110, P < 0.01). Los individuos australianos exhibieron relaciones filogenéticas cercanas con un subgrupo de aves de Nueva Zelanda (4 localidades, 22 individuos). Las demás aves de Nueva Zelanda (20 localidades, 106 individuos) fueron filogenéticamente diferentes (≥7% de divergencia en sus secuencias) y exhibieron un mayor grado de variación genética y estructuración geográfica (ϕST = 0.774, P < 0.05). Estos patrones son consistentes con estudios anteriores que sugirieron un origen en Nueva Zelanda seguido por una colonización más reciente hacia Australia, con un nuevo evento de dispersión hacia Nueva Zelanda. Los procesos de extinción y restablecimiento pueden haber sido factores importantes en el desarrollo de la estructuración genética a través de un amplio rango de escalas de espacio y tiempo. Los datos genéticos son consistentes con la sugerencia de que existe una única subespecie en Australia, pero no con la distribución de las subespecies que ha sido sugerida en Nueva Zelanda con base en la morfología y la coloración.

Influence of fasting during moult on the faecal microbiota of penguins.

Many seabirds including penguins are adapted to long periods of fasting, particularly during parts of the reproductive cycle and during moult. However, the influence of fasting on the gastrointestinal (GI) microbiota has not been investigated in seabirds. Therefore, the present study aimed to examine the microbial composition and diversity of the GI microbiota of fasting little (Eudyptula minor) and king penguins (Aptenodytes patagonicus) penguins during early and late moult. The results from this study indicated that there was little change in the abundance of the major phyla during moult, except for a significant increase in the level of Proteobacteria in king penguins. In king penguins the abundance of Fusobacteria increases from 1.73% during early moult to 33.6% by late moult, whilst the abundance of Proteobacteria (35.7% to 17.2%) and Bacteroidetes (19.5% to 11%) decrease from early to late moult. In little penguins, a decrease in the abundances of Firmicutes (44% to 29%) and an increase in the abundance of Bacteroidetes (11% to 20%) were observed from early to late moult respectively. The results from this study indicate that the microbial composition of both king and little penguins alters during fasting. However, it appears that the microbial composition of king penguins is more affected by fasting than little penguins with the length of fast the most probable cause for this difference.