Publications

annual cycle of sex steroids in the yellow-eyed penguin (megadyptes antipodes) on south island, new zealand.	the yellow-eyed penguin (megadyptes antipodes) is a rare penguin restricted to the south island and some offshore islands of new zealand. it is the least colonial of the penguins but shares with many other penguins a distinct breeding season with a short, synchronised period of egg-laying. blood samples were collected throughout the year from yellow-eyed penguins on the otago peninsula, south island in order to characterise relationships between steroid hormone levels and events of the breeding ...	1994	8045361
aspergillus spp. seropositivity in new zealand penguins.	one hundred-fifty yellow-eyed penguins (megadyptes antipodes) of 8 populations, 20 little blue penguins (eudyptula minor) of 2 populations, 9 rockhopper penguins (eudyptes chrysocome), and 5 adelie penguins (pygoscelis adeliae) from new zealand (nz) and antarctica (latitude range; 39 degrees 30' s - 77 degrees 13' s) were tested by indirect enzyme-linked immunosorbent assays (elisa) for fungal aspergillus spp. igg. one hundred-ten of 184 (60%) penguins were seropositive, and seroprevalence was r ...	1995	8587585
deaths in yellow-eyed penguins (megadyptes antipodes) on the otago peninsula during the summer of 1990.	about 150 rare, adult, yellow-eyed penguins died over a short period during the summer of 1989-1990 on the otago peninsula. these were from a total mainland population estimated at 240 breeding pairs. penguin chicks and non-breeding birds were not affected, but there were indications of shortages in feed supply for birds that bred successfully. thirteen dead penguins were examined. in ten birds, the cause of death was not established. although it was commonly found that adult birds had little or ...	1993	16031693
hormonal correlates of parental behavior in yellow-eyed penguins (megadyptes antipodes).	penguins show varying degrees of brood reduction behavior, from obligate brood reducers to brood maximizers, and we hypothesize that this is associated with differences in prolactin secretion. to address this hypothesis, we determined the breeding season prolactin profile of the yellow-eyed penguin (megadyptes antipodes) for comparison with those of other penguin species found in the literature. we also measured sex steroid plasma concentrations to better characterize the reproductive cycle of t ...	2006	16931082
effects of artificial social stimuli on the reproductive schedule and hormone levels of yellow-eyed penguins (megadyptes antipodes).	the effects of social stimuli on avian reproductive behaviors such as breeding schedules and courtship behaviors are well known due to numerous field studies. however, studies that have simultaneously examined the effects of social stimuli on reproductive behavior and the mediating endocrine mechanisms have been largely restricted to captive populations, which may not be representative of free-living populations. this study, conducted over two breeding seasons, aimed to simultaneously measure th ...	2007	16999958
effects of artificial eggs on prolactin secretion, steroid levels, brood patch development, incubation onset and clutch size in the yellow-eyed penguin (megadyptes antipodes).	several studies have shown that the transition from egg laying to incubation behavior in birds is associated with changes in plasma levels of prolactin and steroid hormones. however, any effect of the tactile and visual input provided by eggs at initiating these hormonal changes has not been fully investigated in wild birds. a few days before yellow-eyed penguins, megadyptes antipodes, started egg laying, we placed an artificial egg into their nests or under cages next to their nest. we then inv ...	2007	17324416
elevated hormonal stress response and reduced reproductive output in yellow-eyed penguins exposed to unregulated tourism.	the endangered, endemic yellow-eyed penguin (megadyptes antipodes) is one of the flagship species for new zealand's wildlife tourism, and recently concern has been raised that tourism-related pressures may be becoming too great. we compared two neighbouring breeding areas exposed to different levels of human disturbance. penguins at the site exposed to unregulated tourism showed significantly lower breeding success and fledging weights than those in an area visited infrequently for monitoring pu ...	2007	17400221
avian malaria (plasmodium spp) in yellow-eyed penguins: investigating the cause of high seroprevalence but low observed infection.	to investigate the cause of a high seroprevalence of antibodies to plasmodium spp known to cause avian malaria, but extremely low levels of observed infection, in yellow-eyed penguins, megadyptes antipodes.	2007	17676079
relict or colonizer? extinction and range expansion of penguins in southern new zealand.	recent human expansion into the pacific initiated a dramatic avian extinction crisis, and surviving taxa are typically interpreted as declining remnants of previously abundant populations. as a case in point, new zealand's endangered yellow-eyed penguin (megadyptes antipodes) is widely considered to have been more abundant and widespread in the past. by contrast, our genetic and morphological analyses of prehistoric, historic and modern penguin samples reveal that this species expanded its range ...	2009	19019791
multilocus assignment analyses reveal multiple units and rare migration events in the recently expanded yellow-eyed penguin (megadyptes antipodes).	the identification of demographically independent populations and the recognition of management units have been greatly facilitated by the continuing advances in genetic tools. managements units now play a key role in short-term conservation management programmes of declining species, but their importance in expanding populations receives comparatively little attention. the endangered yellow-eyed penguin (megadyptes antipodes) expanded its range from the subantarctic to new zealand's south islan ...	2009	19457203
lost in translation or deliberate falsification? genetic analyses reveal erroneous museum data for historic penguin specimens.	historic museum specimens are increasingly used to answer a wide variety of questions in scientific research. nevertheless, the scientific value of these specimens depends on the authenticity of the data associated with them. here we use individual-based genetic analyses to demonstrate erroneous locality information for archive specimens from the late nineteenth century. specifically, using 10 microsatellite markers, we analysed 350 contemporary and 43 historic yellow-eyed penguin (megadyptes an ...	2010	20007185
discospondylitis in a yellow-eyed penguin (megadyptes antipodes).	a 1-year-old female yellow-eyed penguin (megadyptes antipodes) was diagnosed with chronic discospondylitis on the basis of clinical signs and results of hematologic tests, radiography, and computed tomography. despite significant destruction of the affected vertebral bodies and gross malformation of the spine, neurologic function was unaffected. treatment with antibiotics, antifungals, and swimming physiotherapy was attempted, but the bird died after 40 days of hospitalization. histopathologic l ...	2010	20496606
prevalence of leucocytozoon spp, in the endangered yellow-eyed penguin megadyptes antipodes.	yellow-eyed penguins on stewart island were identified with a leucocytozoon spp. of a novel lineage in association with a high regional incidence of chick mortality (n=32, 100% mortality) during the november 2006 to january 2007 breeding season. fourteen chicks from stewart island were examined post-mortem and histologically for leucocytozoon infection. in addition, a survey of blood to detect leucocytozoon spp. infections using pcr was performed on 107 yellow-eyed penguins from 4 distinct nesti ...	2010	20557665
isolation and characterization of microsatellite loci from the yellow-eyed penguin (megadyptes antipodes).	twelve microsatellite loci were isolated and characterized in the endangered yellow-eyed penguin (megadyptes antipodes) using enriched genomic libraries. polymorphic loci revealed two to eight alleles per locus and observed heterozygosity ranged from 0.21 to 0.77. these loci will be suitable for assessing current and historical patterns of genetic variability in yellow-eyed penguins.	2008	21585966
bilateral coxofemoral degenerative joint disease in a juvenile male yellow-eyed penguin (megadyptes antipodes).	a juvenile, male, yellow-eyed penguin (megadyptes antipodes) with abnormal stance and decreased mobility was captured, held in captivity for approximately 6 weeks, and euthanized due to continued clinical signs. radiographically, there was bilateral degenerative joint disease with coxofemoral periarticular osteophyte formation. grossly, the bird had bilaterally distended, thickened coxofemoral joints with increased laxity, and small, roughened and angular femoral heads. histologically, the left ...	2011	21812716
biological plasticity in penguin heat-retention structures.	insulation and vascular heat-retention mechanisms allow penguins to forage for a prolonged time in water that is much cooler than core body temperature. wing-based heat retention involves a plexus of humeral arteries and veins, which redirect heat to the body core rather than to the wing periphery. the humeral arterial plexus is described here for eudyptes and megadyptes, the only extant penguin genera for which wing vascular anatomy had not previously been reported. the erect-crested (eudyptes ...	2012	22213564
high prevalence of leucocytozoon spp. in the endangered yellow-eyed penguin (megadyptes antipodes) in the sub-antarctic regions of new zealand.	yellow-eyed penguins (yeps) have suffered major population declines over the past 30 years, with no single cause established. leucocytozoon was first identified in yellow-eyed penguins in 2005. during the 2008/09 breeding season, a high mortality was seen in both mainland yellow-eyed penguins as well as those on enderby island of the auckland islands archipelago. a high overall prevalence of leucocytozoon spp. in association with a high incidence of chick mortality was observed during this perio ...	2013	23361092
investigation of an outbreak of craniofacial deformity in yellow-eyed penguin (megadyptes antipodes) chicks.	to investigate an outbreak of severe craniofacial deformity in yellow-eyed penguin (megadyptes antipodes, hōiho) chicks at a single breeding site on the otago peninsula in the south island of new zealand.	2014	24841759
heart rate responses provide an objective evaluation of human disturbance stimuli in breeding birds.	intuition is a poor guide for evaluating the effects of human disturbance on wildlife. using the endangered yellow-eyed penguin, megadyptes antipodes, as an example, we show that heart rate responses provide an objective tool to evaluate human disturbance stimuli and encourage the wider use of this simple and low-impact approach. yellow-eyed penguins are a flagship species for new zealand's wildlife tourism; however, unregulated visitor access has recently been associated with reduced breeding s ...	2013	27293597
forced molt in four juvenile yellow-eyed penguins (megadyptes antipodes).	penguins are dependent on waterproof plumage for survival. the molt in sub-antarctic penguin species is a seasonal and catastrophic process during which the animals go through periods of fasting and high levels of stress. their entire plumage is usually replaced in 3 wk. attempts at consistent hormonal induction of molt in penguins have been unsuccessful. four yellow-eyed penguins ( megadyptes antipodes ) were referred for treatment at wildbase, massey university, palmerston north, new zealand, ...	2016	27505039
novel morphological and molecular data for corynosoma hannae zdzitowiecki, 1984 (acanthocephala: polymorphidae) from teleosts, fish-eating birds and pinnipeds from new zealand.	the polymorphid acanthocephalan, corynosoma hannae zdzitowiecki, 1984 is characterised on the basis of newly collected material from a new zealand sea lion, phocarctos hookeri (gray), and long-nosed fur seal, arctophoca forsteri (lesson) (definitive hosts), and from stewart island shags, leucocarbo chalconotus (gray), spotted shags, phalacrocorax punctatus (sparrman) and yellow-eyed penguins, megadyptes antipodes (hombron & jacquinot) (non-definitive hosts) from new zealand. specimens are descri ...	2017	27765681
diphtheritic stomatitis in yellow-eyed penguins (megadyptes antipodes) in new zealand.	diphtheritic stomatitis is a seasonal disease that has been recognized as a syndrome in yellow-eyed penguin ( megadyptes antipodes ) chicks in new zealand for >10 yr. it was present in about 50% of 234 chicks examined since 2002 and is characterized by a thick serocellular exudate in the oral cavity of 1-4-wk-old chicks. the syndrome includes inanition, weight loss, and death in many affected birds. microscopically, the lesions varied in severity. most affected chicks had severe, locally extensi ...	2017	27788054
investigation of a mortality cluster in wild adult yellow-eyed penguins (megadyptes antipodes) at otago peninsula, new zealand.	we investigated an epidemic mortality cluster of yellow-eyed penguins (megadyptes antipodes) that involved 67 moribund or dead birds found on various beaches of the otago peninsula, new zealand, between january 21 and march 20, 2013. twenty-four carcases were examined postmortem. histological lesions of pulmonary, hepatic and splenic erythrophagocytosis and haemosiderosis were found in 23 of 24 birds. fifteen birds also had haemoglobin-like protein droplets within renal tubular epithelial cells. ...	2016	27919180
evidence for high inter-generational individual quality in yellow-eyed penguins.	longitudinal studies focusing on lifetime reproductive success (lrs) have been used to measure individual breeding performance and identify commonalities among successful breeders. by extending the focus to subsequent generations we identify a proportion of high-quality individuals that contribute disproportionately to the population over multiple generations. we used 23 years of yellow-eyed penguin (megadyptes antipodes) breeding data from one breeding area to identify the proportion of individ ...	2017	28265492
quantifying climate change impacts emphasises the importance of managing regional threats in the endangered yellow-eyed penguin.	climate change is a global issue with effects that are difficult to manage at a regional scale. yet more often than not climate factors are just some of multiple stressors affecting species on a population level. non-climatic factors-especially those of anthropogenic origins-may play equally important roles with regard to impacts on species and are often more feasible to address. here we assess the influence of climate change on population trends of the endangered yellow-eyed penguin (megadyptes ...	2017	28533952
a global overview of exposure levels and biological effects of trace elements in penguins.	trace elements are chemical contaminants that can be present almost anywhere on the planet. the study of trace elements in biotic matrices is a topic of great relevance for the implications that it can have on wildlife and human health. penguins are very useful, since they live exclusively in the southern hemisphere and represent about 90% of the biomass of birds of the southern ocean. the levels of trace elements (dry weight) in different biotic matrices of penguins were reviewed here. maps of ...	2018	29079931
mitogenomes uncover extinct penguin taxa and reveal island formation as a key driver of speciation.	the emergence of islands has been linked to spectacular radiations of diverse organisms. although penguins spend much of their lives at sea, they rely on land for nesting, and a high proportion of extant species are endemic to geologically young islands. islands may thus have been crucial to the evolutionary diversification of penguins. we test this hypothesis using a fossil-calibrated phylogeny of mitochondrial genomes (mitogenomes) from all extant and recently extinct penguin taxa. our tempora ...	2019	30722030
applying science to pressing conservation needs for penguins.	more than half of the world's 18 penguin species are declining. we, the steering committee of the international union for conservation of nature species survival commission penguin specialist group, determined that the penguin species in most critical need of conservation action are african penguin (spheniscus demersus), galápagos penguin (spheniscus mendiculus), and yellow-eyed penguin (megadyptes antipodes). due to small or rapidly declining populations, these species require immediate scienti ...	2020	31257646
genomic characterisation of a novel avipoxvirus isolated from an endangered yellow-eyed penguin (megadyptes antipodes).	emerging viral diseases have become a significant concern due to their potential consequences for animal and environmental health. over the past few decades, it has become clear that viruses emerging in wildlife may pose a major threat to vulnerable or endangered species. diphtheritic stomatitis, likely to be caused by an avipoxvirus, has been recognised as a significant cause of mortality for the endangered yellow-eyed penguin (megadyptes antipodes) in new zealand. however, the avipoxvirus that ...	2021	33525382