Lloyd S. Davis

Carotenoid-derived ornaments reflect parental quality in male and female yellow-eyed penguins (Megadyptes antipodes)

The handicap principle suggests that ornamental traits that function as honest signals in mate selection must be costly to be effective. We evaluated in the sexually monochromatic yellow-eyed penguin (Megadyptes antipodes) whether the carotenoid-derived plumage and eye coloration predicts parental quality and whether males and females within pairs mate assortatively in relation to these carotenoid-derived ornaments. In addition, we investigated whether age or body condition was related to the coloration of the ornamental traits. In yellow-eyed penguins, parental quality of males and females was predicted by eye and head plumage coloration. Even when we controlled for gender- and age-specific differences, eye and head plumage coloration reflected honestly parental quality. Males and females mated assortatively in relation to these ornamental traits. While age influenced coloration of both the eye and head plumage, body condition was related only to the saturation of plumage coloration. These results provide evidence that the carotenoid-derived ornaments in yellow-eyed penguins reflect the parental abilities of birds and, therefore, may be costly signals. Potentially, female and male yellow-eyed penguins could use eye and plumage coloration as an indirect cue in assessing age and quality of individual birds during mate choice. This is only the second study to examine plumage coloration in relation to sexual selection in penguins, while conspicuous ornamental traits in other species of penguin beg the question whether they also play a role in sexual selection.

Satellite telemetry of the winter migration of Adélie penguins (Pygoscelis adeliae)

Adélie penguins (Pygoscelis adeliae), after breeding in Antarctica during the austral summer, undergo a winter migration before returning to the breeding grounds 8 months later. It is the major source of adult mortality, with about a quarter of them not returning. Here we describe the first attempt to track the winter migration of Adélie penguins using satellite telemetry. Transmitters were attached to two penguins on 16 February 1991 after their post-breeding moult at Cape Bird, Ross Island, Antarctica. Transmissions were received from one penguin (bird #1) for 4.4 months, during which time it travelled 2792.6 km from the rookery (nearly 1500 km straight-line distance). Transmissions were received from the other penguin (bird #2) for 2.5 months during which time it followed a path remarkably similar to that of bird #1. The penguins travelled northwards up the coast of Victoria Land, keeping within 100 km of the coast, rounding Cape Adare soon after 29 March and were midway between the Balleny Islands and the Antarctic coast on 3 May. Thereafter, the record from bird #1 shows that it travelled further westwards until, when opposite the Mastusevich Glacier Tongue of the Mastusevich Glacier, it turned due north and moved away from the coast. By 29 June, when transmissions ended, its progression had slowed and it was northwest of the Balleny Islands near a zone where pack ice covered 75% of the surface of the sea. Two novel points that arise from this study are: (1) that Adélie penguins from Cape Bird undergo winter migrations of not less than 5000 km, and (2) that they may be travelling to common overwinter feeding grounds.

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.

Satellite Tracking of Magellanic Penguin Migration

We tracked four male Magellanic Penguins (Spheniscus magellanicus) from the beginning of their winter migration for periods ranging from three to six weeks. Upon leaving the colony at Punta Tombo, Argentina where they had bred and molted, all four birds traveled northeast along the coast at speeds consistent with sighting and band-return data which suggest a round-trip winter migration in this species of up to several thousand kilometers. Three of the birds followed a similar route, moved at approximalely the same rate, and were still moving northeastward at a distance of over 800 km from the colony when signals ceased. The fourth bird departed from the northeast route at approximately 300 km into its trip and remained in a large bay for at least 29 days, when the last signal was received. Initially, the birds traveled rapidly and made few deep dives. Later, their rate of travel slowed, their paths became more erratic, and they made more deep dives, all indications of probable foraging. This suggests that location of the penguin migration route and rate of travel along it may be determined by seasonal movement of prey. As all birds were within 250 km of shore for the entire period in which signals were received, our results underscore the importance of controlling pollution associated with petroleum transport along the coast of Argentina, currently a major source of Magellanic Penguin mortality.

Modeling tag loss in New Zealand fur seal pups

Mark-recapture studies of pinnipeds commonly use double-tagging to reduce bias of parameter estimates and to allow estimation of tag retention rates. However, most tag retention estimates assume independence of tag loss. Here we were able to identify when individual New Zealand fur seal (Arctocephalus forsteri) pups had lost both tags ; therefore, we tested the assumption of no association between the tag-loss rates of left and right tags. We also tested for differences in tag retention among three different types of plastic tag (Allflex® cattle, mini and button tags), between two attachment types (i.e., fixed or swivel), and whether retention varied among years and colonies sampled. We found strong evidence of within-individual tag loss association for most tags in most years, but little evidence that this varied among colonies. We found that ignoring within-individual association of tag loss led to a bias in estimated tag retention of 7.4-10.1%. Smaller rocks and greater crevice and ledge densities in colonies were associated with lower probabilities of tag retention. We suggest researchers should attempt to use permanent marks in combination with tags to assess unbiased estimates of tag retention.

A sensitivity analysis of hutton's shearwater: prioritizing conservation research and management

Huttons shearwater Puffinus huttoni is an endangered seabird that breeds at just two colonies, which are subject to predation from introduced mammals. Whether the remaining populations are stable is unknown. In order to help focus future research and management into key areas, we developed a population model of Huttons shearwaters. The model incorporated environmental variation and also included uncertainty in the estimation of both the mean and the between-year variation of parameters. The sensitivity analysis indicated that the population growth rate of the model was most influenced by the values of mean adult survival, recruitment and the between-year variation in adult survival. In contrast, the model was relatively robust to variation in the mean and between-year variation of most breeding parameters. Future research would best be directed away from measuring breeding parameters alone and focused on determining causes of adult and juvenile mortality such as by-catch at sea and numbers of adults preyed upon by stoats (Mustela erminea). It is important to assess both average rates of mortality and between-year variation in this rate.

The State of Science Communication Programs at Universities Around the World

Building on discussions at two workshops held at the recent 10th International Conference on the Public Communication of Science and Technology during June 2008 in Malmö, Sweden, this article proposes specific steps toward achieving a common understanding of the essential elements for academic programs in science communication. About 40 academics, science communication professionals, and students from at least 16 countries participated in this process.

Satellite tracking of Adélie penguins

SummaryFemale Adélie penguins (Pygoscelis adeliae) that take too long on their first post-laying foraging trip are a major cause of breeding failure, but in the ice-filled waters of Antarctica, determining where they go and why they are away so long has proved difficult. Here we describe the first successful attempt to track penguins at sea using satellite telemetry. Four females foraged in different locations, dispelling the notion of a common feeding ground. They moved up to 272 km from the rookery and covered from 551 to 1,121 km on their trips, swimming at minimum average speeds around 1.2 m/s. The birds were most likely to be in the water between 0630 and 1430 when light intensity, important for a visual predator, was greatest. Carrying the transmitters reduced rates of fat deposition (weight gain), increasing the duration of foraging trips of females, and suggested that they may forage until their fat depots reach a minimum threshold level. This has two implications: (i) durations of these postlaying foraging trips could potentially be used as an indicator of krill abundance (Euphausia sp), the almost exclusive food of Adélie penguins during this period, and (ii) any reduction in krill stocks caused by harvesting could increase foraging trip durations with a concomitant increase mi breeding failures.

Using artificial neural networks to model the suitability of coastline for breeding by New Zealand fur seals (Arctocephalus forsteri )

Abstract New Zealand fur seal ( Arctocephalus forsteri ) numbers and distribution were reduced by human exploitation but the species is now re-colonizing much of its former range. Pinnipeds occupy two different habitat media: the marine (feeding) and terrestrial (breeding) environments. Measures of geographic variation in both these environments can be modelled together to predict coastline suitability for colonization (i.e. potential availability of breeding sites). To avoid problems of non-linear modelling, we used an artificial neural network (ANN) to: (1) predict the suitability of coastline in South Island, New Zealand to support breeding A. forsteri colonies by creating a model using pup condition (measured from 20 breeding colonies during 1996–98), prey distribution and abundance, bathymetry, and the type of coastal substrate; (2) compare the predicted distribution of suitable coastline for colonization from the model to the current distribution of A. forsteri colonies ( n =198 colonies); and (3) using ANN inference rule extraction, determine which factors are the most influential in predicting coastline suitability. ANN model predictions overlapped current distributions of A. forsteri colonies in South Island. Inference rule extraction gave good predictions of colony performance (i.e. the ability to predict observed pup condition); however, they were not consistent among years in terms of the prey species constituting the rules or in the direction of the relationships. Arrow squid and octopus were important model terms in 1996 and 1997, but the direction of their coefficients in the inference rules were opposite between years. Hoki was an important term in 1997 and 1998, but it also varied in direction between years. Terms of secondary importance include the distance from sample colonies to 250 m-, 500 m- and 1000 m-isobaths. Variation in model predictions may result from climatic variation, the constant index of prey availability that was used and the potential for A. forsteri to switch main prey species among year. Resource availability appears to be a good predictor of the potential distribution of A. forsteri colonies, but future models should attempt to incorporate indices of temporal variation in resource availability as well as population density to better predict the colonization process and understand the ecological mechanisms operating within.

Prolonged foraging trips and egg desertion in little penguins (Eudyptula minor)

Abstract Penguins share incubation duties between the male and female of a pair. The one left on the nest must fast while its partner is foraging at sea. Nest attendance patterns during the incubation period reflect the way time is allocated between the conflicting demands of incubation and foraging. We conducted daily nest checks for little penguins (Eudyptula minor) at two localities in New Zealand (Motuara Island in the Marlborough Sounds and Oamaru, Otago) in the 1998/99 breeding season and found significant variation in nest attendance between the two areas. Penguins breeding at Motuara Island made significantly longer foraging trips and were in poorer body condition than those breeding at Oamaru. Foraging trip durations were significantly correlated with the body condition of birds at both areas: the poorer the condition, the longer the foraging trip durations. The increased risk of egg desertion observed at Motuara Island is probably a consequence of the prolonged foraging trips that limit the time available for incubation.