Publications

malignant melanomas in a penguin (eudyptes chrysolophus) and a red-tailed hawk (buteo jamaicensis).		1992	1514222
reproductive endocrinology of macaroni (eudyptes chrysolophus) and gentoo (pygoscelis papua) penguins. i. seasonal changes in plasma levels of gonadal steroids and lh in breeding adults.	changes in plasma luteinizing hormone (lh), testosterone, oestradiol, and progesterone were measured throughout the breeding and molt cycle in free-living male and female macaroni (eudyptes chrysolophus) and gentoo (pygoscelis papua) penguins, at bird island, south georgia (54 degrees s, 38 degrees w). these two species are sympatric but have a markedly different breeding cycle. in macaroni penguins plasma levels of all hormones, except lh in males, were significantly elevated at the time of arr ...	1992	1601255
reproductive endocrinology of macaroni (eudyptes chrysolophus) and gentoo (pygoscelis papua) penguins. ii. plasma levels of gonadal steroids and lh in immature birds in relation to deferred sexual maturity.	plasma levels of lh, testosterone, estradiol, and progesterone were measured, during the breeding season, in adult and immature macaroni (eudyptes chrysolophus) and gentoo (pygoscelis papua) penguins, at bird island, south georgia (54 degrees s, 38 degrees w), in relation to deferred sexual maturity. macaroni penguins do not breed until 6-8 years of age whereas gentoo penguins first breed at 2 years of age. plasma lh was elevated in 3- to 5-year-old macaroni penguins, but not in 1- to 2-year-old ...	1992	1601256
notes on parasites in penguins (spheniscidae) and petrels (procellariidae) in the antarctic and sub-antarctic.	blood smears were examined from 143 penguins of four species (aptenodytes patagonicus, eudyptes chrysolophus, e. schlegeli, and pygoscelis gentoo) from sub-antarctic macquarie island and heard island. no blood parasites were reported. the vectors of hepatozoon albatrossi (reported from three species of albatross) are probably shared by penguins, and it is suggested that the latter are not susceptible to infection with this protozoan. cestodes of the genus tetrabothrius were present in large numb ...	1988	3352088
[morphologico-functional study of the locomotor system of penguins as a principle of the general motor model of "underwater flight." ii].	based on the statements in part i according to the evolution of the underwater flight, its biophysical consequences and summarizing our knowledge on swimming performances of penguins, the active and passive apparatus of movement was studied by dissection of 26 individuals of pygoscelis papua, p. antarctica, p. adeliae, eudyptes chrysolophus, and aptenodytes forsteri. besides the functional explanation of the articulatio sternocoracoidea (diverging considerably from the usual type in birds), a ne ...	1986	3569810
[morphologic-functional study of the locomotor system of penguins as a general model of movement in under-water flight. i].	regarding several theories of the evolution of the sphenisciformes the specific morpho-physiological alterations for the changeover from aerial to underwater life are discussed. the peculiarities in the penguin's "construction" become comprehensible as strong adjustments to the subaquatic locomotion. surely they took their origin from the equipment of flying birds. the present data of the kinematics of the underwater locomotion show, that propulsion is produced in the same principal way by the f ...	1986	3803859
ontogeny of haemoglobin in the royal penguin eudyptes chrysolophus schlegeli.		1970	5491990
plasma prolactin during the breeding season in adult and immature macaroni (eudyptes chrysolophus) and gentoo (pygoscelis papua) penguins.	plasma prolactin levels were measured in free-living breeding adult and immature (pre-breeding) macaroni (eudyptes chrysolophus) and gentoo (pygoscelis papua) penguins at bird island, south georgia (54 degrees s, 38 degrees w). macaroni and gentoo penguins first breed at 5-6 and 2 years of age, respectively. in adult birds, of both species, prolactin was low (< 1.0 microgram. liter-1) during the courtship period and then increased during early (gentoo) to mid (macaroni) incubation (to 3.9-4.7 an ...	1993	8138101
distribution and abundance of the tick ixodes uriae in a diverse subantarctic seabird community.	at bird island, south georgia, we surveyed the distribution and abundance of ticks on the vertebrate fauna and found only 1 species ixodes uriae. we classified all seabird species into 3 groups: (1) seabirds nesting on the surface of the ground solitarily, in dispersed groups of a few nests, or in colonies with well-spaced nests; (2) seabirds nesting on the surface of the ground in dense colonies; and (3) seabirds nesting in dense colonies in burrows or rock crevices. we detected i. uriae only o ...	1999	10207358
isolation and characterization of campylobacter jejuni subsp. jejuni from macaroni penguins (eudyptes chrysolophus) in the subantarctic region.	on bird island, south georgia, albatrosses (n = 140), penguins (n = 100), and fur seals (n = 206) were sampled for campylobacter jejuni. c. jejuni subsp. jejuni was recovered from three macaroni penguins (eudyptes chrysolophus). these isolates, the first reported for the subantarctic region, showed low genetic diversity and high similarity to northern hemisphere c. jejuni isolates, possibly suggesting recent introduction to the area.	2000	10618265
heart rate and rate of oxygen consumption of exercising macaroni penguins.	twenty-four macaroni penguins (eudyptes chrysolophus) from three groups, breeding males (n=9), breeding females (n=9) and moulting females (n=6), were exercised on a variable-speed treadmill. heart rate (fh) and mass-specific rate of oxygen consumption (svo2) were recorded from the animals, and both fh and svo2 were found to increase linearly with increasing treadmill speed. a linear regression equation described the relationship between fh and svo2 for each individual. there were no significant ...	2001	11171349
life cycle of the tick ixodes uriae in penguin colonies: relationships with host breeding activity.	a survey of the temporal pattern of population structure and feeding activity of the seabird tick ixodes uriae was conducted for the first time in two host species colonies: king penguin (aptenodytes patagonicus halli) and macaroni penguin (eudyptes chrysolophus chrysolophus). the life cycle of the tick was investigated over 3 years in a king penguin colony and 2 years in a macaroni penguin colony at possession island (crozet archipelago). there was a marked seasonal feeding activity pattern of ...	2001	11429167
levels and interactions of heavy metals in sea birds from svalbard and the antarctic.	samples of liver and kidney from 92 seabirds of ten species collected on spitsbergen and in the antarctic, were analysed for their content of copper, zinc, cadmium, lead, mercury and selenium. significantly higher levels of copper and zinc were observed in birds from spitsbergen than in those from the antarctic, while the opposite was true for selenium. the highest cadmium levels were found in fulmar fulmarus glacialis and macaroni penguin eudyptes chrysolophus. a possibility of kidney damage du ...	1987	15092711
allometric estimation of metabolic rate from heart rate in penguins.	studies of the relationship between heart rate (f(h)) and rate of oxygen consumption (v(.) (o(2))), which are then used to predict field metabolic rate, frequently fail to incorporate body mass as a predictive variable. this is a potentially important omission in the study of animals whose body mass fluctuates substantially during their annual cycle. in an attempt further to improve estimates of field metabolic rate from f(h), we re-evaluated data on m(b), f(h) and v(.) (o(2)) from previous stud ...	2005	16297646
genetic isolation and divergence in sexual traits: evidence for the northern rockhopper penguin eudyptes moseleyi being a sibling species.	the taxonomic status of populations of rockhopper penguins (eudyptes chrysocome) is still enigmatic. northern populations differ from southern ones in breeding phenology, song characteristics and head ornaments used as mating signals. we conducted a molecular analysis using mitochondrial dna sequencing to test if there is a gene flow barrier between northern (subtropical) populations and southern (subantarctic) populations in relation to the subtropical convergence, a major ecological boundary f ...	2006	16968279
estimating the rate of oxygen consumption during submersion from the heart rate of diving animals.	how animals manage their oxygen stores during diving and other breath-hold activities has been a topic of debate among physiologists for decades. specifically, while the behavior of free-ranging diving animals suggests that metabolism during submersion must be primarily aerobic in nature, no studies have been able to determine their rate of oxygen consumption during submersion (vo(2)d) and hence prove that this is the case. in the present study, we combine two previously used techniques and deve ...	2007	17218442
studying seabird diet through genetic analysis of faeces: a case study on macaroni penguins (eudyptes chrysolophus).	determination of seabird diet usually relies on the analysis of stomach-content remains obtained through stomach flushing; this technique is both invasive and logistically difficult. we evaluate the usefulness of dna-based faecal analysis in a dietary study on chick-rearing macaroni penguins (eudyptes chrysolophus) at heard island. conventional stomach-content data was also collected, allowing comparison of the approaches.	2007	17786203
where do penguins go during the inter-breeding period? using geolocation to track the winter dispersion of the macaroni penguin.	although penguins are key marine predators from the southern ocean, their migratory behaviour during the inter-nesting period remains widely unknown. here, we report for the first time, to our knowledge, the winter foraging movements and feeding habits of a penguin species by using geolocation sensors fitted on penguins with a new attachment method. we focused on the macaroni penguin eudyptes chrysolophus at kerguelen, the single largest consumer of marine prey among all seabirds. overall, macar ...	2009	19447814
a carryover effect of migration underlies individual variation in reproductive readiness and extreme egg size dimorphism in macaroni penguins.	where life-history stages overlap, there is the potential for physiological conflicts that might be important in mediating carryover effects. however, our knowledge of the specific physiological mechanisms underlying carryover effects remains rudimentary, and specific examples remain rare. here we show that female macaroni penguins (eudyptes chrysolophus) initiate vitellogenesis and yolk formation while at sea during return migrations to breeding colonies; yolk formation takes approximately 16 d ...	2010	20636133
isolation and characterization of macaroni penguin (eudyptes chrysolophus) microsatellite loci and their utility in other penguin species (spheniscidae, aves).	we report the characterization of 25 microsatellite loci isolated from the macaroni penguin (eudyptes chrysolophus). thirteen loci were arranged into four multiplex sets for future genetic studies of macaroni penguin populations. all 25 loci were tested separately in each of four other penguin species [adélie penguin (pygoscelis adeliae), chinstrap penguin (pygoscelis antarctica), gentoo penguin (pygoscelis papua) and king penguin (aptenodytes patagonicus)]. between eight and 12 loci were polymo ...	2009	21564950
corticosterone predicts foraging behavior and parental care in macaroni penguins.	corticosterone has received considerable attention as the principal hormonal mediator of allostasis or physiological stress in wild animals. more recently, it has also been implicated in the regulation of parental care in breeding birds, particularly with respect to individual variation in foraging behavior and provisioning effort. there is also evidence that prolactin can work either inversely or additively with corticosterone to achieve this. here we test the hypothesis that endogenous cortico ...	2012	22673661
vibrational spectroscopic analyses of unique yellow feather pigments (spheniscins) in penguins.	many animals extract, synthesize and refine chemicals for colour display, where a range of compounds and structures can produce a diverse colour palette. feather colours, for example, span the visible spectrum and mostly result from pigments in five chemical classes (carotenoids, melanins, porphyrins, psittacofulvins and metal oxides). however, the pigment that generates the yellow colour of penguin feathers appears to represent a sixth, poorly characterized class of feather pigments. this pigme ...	2013	23516063
ocular findings and reference values for selected ophthalmic diagnostic tests in the macaroni penguin (eudyptes chrysolophus) and southern rockhopper penguin (eudyptes chrysocome).	to describe ophthalmic examination findings and standard diagnostic test results in 2 penguin species.	2015	24238103
survival in macaroni penguins and the relative importance of different drivers: individual traits, predation pressure and environmental variability.	understanding the demographic response of free-living animal populations to different drivers is the first step towards reliable prediction of population trends. penguins have exhibited dramatic declines in population size, and many studies have linked this to bottom-up processes altering the abundance of prey species. the effects of individual traits have been considered to a lesser extent, and top-down regulation through predation has been largely overlooked due to the difficulties in empirica ...	2014	24846695
malignant melanoma in the penguin: characterization of the clinical, histologic, and immunohistochemical features of malignant melanoma in 10 individuals from three species of penguin.	malignant melanomas are aggressive neoplasms that are relatively common in penguins compared to other avian species. in this study, the clinical and pathologic characteristics of melanocytic neoplasms in five macaroni (eudyptes chrysolophus), three rock hopper (eudyptes chrysocome), and two humboldt (spheniscus humboldti) penguins are described. tumors most commonly occurred in the skin of the foot or hock, and were seen in the subcutaneous muscle, especially near the beak/oral cavity. gross les ...	2014	25314820
love thy neighbour or opposites attract? patterns of spatial segregation and association among crested penguin populations during winter.	competition for food among populations of closely related species and conspecifics that occur in both sympatry and parapatry can be reduced by interspecific and intraspecific spatial segregation. according to predictions of niche partitioning, segregation is expected to occur at habitat boundaries among congeners and within habitats among conspecifics, while negative relationships in the density of species or populations will occur in areas of overlap. we tested these predictions by modelling th ...	2014	25505357
diagnosis of retrobulbar round cell neoplasia in a macaroni penguin ( eudyptes chrysolophus ) through use of computed tomography.	a 25-year-old female macaroni penguin (eudyptes chrysolophus) was diagnosed with exophthalmos secondary to retrobulbar neoplasia through use of computed tomography (ct). histopathologic examination of the mass supported a diagnosis of malignant round cell neoplasia. immunohistochemical (ihc) labeling was applied to determine cell origin; the neoplastic cells did not label with t-cell marker cd3 or b-cell marker bla.36 and could not be further characterized. the scleral ossicles precluded evaluat ...	2015	25867665
increasing accuracy: a new design and algorithm for automatically measuring weights, travel direction and radio frequency identification (rfid) of penguins.	a fully automated weighbridge using a new algorithm and mechanics integrated with a radio frequency identification system is described. it is currently in use collecting data on macaroni penguins (eudyptes chrysolophus) at bird island, south georgia. the technology allows researchers to collect very large, highly accurate datasets of both penguin weight and direction of their travel into or out of a breeding colony, providing important contributory information to help understand penguin breeding ...	2015	25894763
influence of oceanographic structures on foraging strategies: macaroni penguins at crozet islands.	in the open ocean, eddies and associated structures (fronts, filaments) have strong influences on the foraging activities of top-predators through the enhancement and the distribution of marine productivity, zooplankton and fish communities. investigating how central place foragers, such as penguins, find and use these physical structures is crucial to better understanding their at-sea distribution. in the present study, we compared the travel heading and speed of the world's most abundant pengu ...	2015	26396739
voriconazole toxicity in multiple penguin species.	aspergillosis is a common respiratory fungal disease in penguins managed under human care. triazole antifungal drugs, including itraconazole, are most commonly used for treatment; however, itraconazole treatment failures from drug resistance are becoming more common, requiring newer treatment options. voriconazole, a newer triazole, is being used more often. until recently, no voriconazole pharmacokinetic studies had been performed in penguins, leading to empiric dosing based on other avian stud ...	2015	26667545
intraocular pressure in southern rockhopper (eudyptes chrysocome) and macaroni penguins (eudyptes chrysolophus): evaluation of influencing factors.	ophthalmic examinations were performed on 160 macaroni penguins (eudyptes chrysolophus) and 90 southern rockhopper penguins (eudyptes chrysocome) at eight north american zoos and aquaria. intraocular pressure (iop) was measured using rebound tonometry while penguins were held in two different body positions. correlations between iop and factors including age, body position, eye pathology, and housing parameters were evaluated. normal macaroni penguins had a mean iop of 42.0 ± 9.7 mm hg. normal r ...	2016	27010282
an evaluation of infrared thermography for detection of bumblefoot (pododermatitis) in penguins.	the objective of this study was to evaluate infrared thermography as a noninvasive screening tool for detection of pododermatitis during the developing and active stages of disease in three species of penguins: king penguin (aptenodytes patagonicus) , macaroni penguin (eudyptes chrysolophus), and rockhopper penguin (eudyptes chrysocome). in total, 67 penguins were examined every 3 mo over a 15-mo period. at each exam, bumblefoot lesions were characterized and measured, and a timed series of ther ...	2016	27468019
evaluation of potential risk factors associated with cataract in captive macaroni (eudyptes chrysolophus) and rockhopper penguins (eudyptes chrysocome).	complete ophthalmic examinations were performed on 160 macaroni penguins ( eudyptes chrysolophus ) and 90 rockhopper penguins ( eudyptes chrysocome ) at eight north american zoological institutions. cataract prevalence in the macaroni population was 46.5% (n = 74) of penguins and 42.3% (135/319) of eyes. cataract prevalence in the rockhopper population was 45.5% (n = 40) of penguins and 40.6% (73/180) of eyes. the mean age of macaroni penguins without ocular disease was 7.4 ± 5.8 yr, while that ...	2016	27691963
unravelling the relative roles of top-down and bottom-up forces driving population change in an oceanic predator.	in the open ocean ecosystem, climate and anthropogenic changes have driven biological change at both ends of the food chain. understanding how the population dynamics of pelagic predators are simultaneously influenced by nutrient-driven processes acting from the "bottom-up" and predator-driven processes acting from the "top-down" is therefore considered an urgent task. using a state-space demographic model, we evaluated the population trajectory of an oceanic predator, the macaroni penguin (eudy ...	2016	27859185
linking extreme interannual changes in prey availability to foraging behaviour and breeding investment in a marine predator, the macaroni penguin.	understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. we documented the behavioural responses and breeding investment of macaroni penguins eudyptes chrysolophus across five breeding seasons where local prey density changed by five-fold; from very low to highly abundant. when prey availability was low, foraging trips were significantly longer and extended overnight. ...	2017	28910405
the tongue as a gripper.	frogs, chameleons and anteaters are striking examples of animals that can grab food using only their tongue. how does the soft and wet surface of a tongue grip onto objects before they are ingested? here, we review the diversity of tongue projection methods, tongue roughnesses and tongue coatings, our goal being to highlight conditions for effective grip and mobility. a softer tongue can reach farther: the frog rana pipiens tongue is 10 times softer than the human tongue and can extend to 130% o ...	2018	29636370
influence of biological factors on hematological and serum biochemistry values in captive adélie, chinstrap, gentoo, and macaroni penguins in pingtung, taiwan.	hematology and serum biochemistry reference values are essential for health evaluation and disease diagnosis in penguins. however, there are currently no published physiological values for captive adélie (pygoscelis adeliae) and chinstrap penguins (p. antarcticus), nor for wild or captive macaroni penguins (eudyptes chrysolophus). the present study is the first investigation regarding hematology and serum biochemistry reference values for captive adélie, gentoo (p. papua), chinstrap, and macaron ...	2018	29722905
case studies of the impacts of cataract surgery on crested penguin welfare.	as nonhuman animals age, geriatric individuals require additional care and veterinary support to ensure their well being. the focus on lifelong care is a relatively newer approach when providing good welfare, and few studies have examined how veterinary care impacts behavior at different ages or how best to accommodate geriatric individuals in zoos. the objectives of this study were to (a) assess both the immediate and long-term (one year later) behavioral impacts of cataract removal for macaron ...	2020	30295508
more than the eye can see: genomic insights into the drivers of genetic differentiation in royal/macaroni penguins across the southern ocean.	the study of systematics in wide-ranging seabirds can be challenging due to the vast geographic scales involved, as well as the possible discordance between molecular, morphological and behavioral data. in the southern ocean, macaroni penguins (eudyptes chrysolophus) are distributed over a circumpolar range including populations in antarctic and sub-antarctic areas. macquarie island, in its relative isolation, is home to a closely related endemic taxon - the royal penguin (eudyptes schlegeli), w ...	2019	31323335
trade-off between aerobic performance and egg production in migratory macaroni penguins.	when successive stages of an organism's life-history overlap, conflicts and trade-offs can emerge due to competition among physiological pathways. for example, long periods of sustained locomotion in migrating birds are supported by the androgenic up-regulation of aerobic factors, such as new red blood cell production and hematocrit. however, towards the end of migration, many female birds begin up-regulating 17ß-estradiol (e2) to support vitellogenesis and egg production, but e2 secretion is kn ...	2020	32535235