Proceedings of the 8th Oamaru Penguin Symposium 2012

Abstract

This paper records the abstracts of the presentations given at the 8th Penguin Symposium, held at the Oamaru Opera House, Ōamaru, New Zealand, 12 and 13 July 2012.

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Proceedings of the 9th Oamaru Penguin Symposium 2014

We have a responsibility to care: New Zealand's penguins, a global perspective

C Gaskin

Royal Forest and Bird Protection Society of New Zealand Inc/BirdLife International, Wellington, New Zealand

Six species of penguin breed in the New Zealand region, one third the global total. Four are endemic to New Zealand; five have a threat ranking of vulnerable or endangered (IUCN). This diversity and concentration of penguins is even more marked if the full extent of New Zealand's biogeographic sub-region is considered, i.e. including Australia's Macquarie Island, nine species in total (Checklist of Birds of NZ). New Zealand also figures strongly as a global ‘hotspot’ for fossil penguins; a heritage that stretches back 58–62 million years. BirdLife International's Important Bird Area (IBA) program aims to identify, monitor and protect key sites for birds globally. IBAs are selected on the basis of internationally agreed criteria, sites that hold one or more globally threatened, endemic or congregatory bird species or highly representative bird assemblages. The program has been adapted and extended to the marine environment. Four major components of seabird lifecycles may be captured by Marine IBAs. In New Zealand, Forest & Bird (BirdLife's New Zealand partner) is working to identify IBAs, first for New Zealand's seabirds, with terrestrial, shore and water birds to follow. Providing accurate population status for all seabird species is vital to this process; a national seabird colony database is being compiled. For penguin species IBAs will include those sites on land that meet the criteria and threshold numbers. In the main these are breeding sites, although other sites of regular use (e.g. moult sites) can also be considered. Determining high-use areas at sea (Marine IBAs) and their identification will make a vital contribution to initiatives for greater protection, including valuable input to the identification of Marine Protected Areas, and contribute to efforts to ensure sustainable management of New Zealand's Exclusive Economic Zone (EEZ).

Chris Gaskin is contracted to Forest & Bird (NZ) and BirdLife International advocating for IBAs.

Snares penguins: population stable?

D Houston^a and J Hiscock^b

^a Department of Conservation, National Office, Auckland, New Zealand; ^b Department of Conservation, Southern Islands Area Office, Invercargill, New Zealand

In 2008 a census of Snares penguins (Eudyptes robustus) on Northeast and Broughton Islands in the Snares Islands suggested that the breeding population had declined by 16% since the previous census in 2000. A repeat census of Northeast and Broughton Islands in 2010 showed a reversal of that decline, with a total nest count of 25,509 on Northeast Island and 5161 on Broughton Island. The Western Chain was not counted in any of the census years and an estimate of 381 nests is derived from counts conducted in 1984 and 1996. This brings the total population estimate to 31,447 breeding pairs. It is believed that low numbers encountered in 2008 only reflect a ‘bad year’ where a portion of the penguin population did not breed. As such there is no evidence for a population decline.

Monitoring erect crested and rockhopper penguins on the Antipodes Islands, October–November 2011

J Hiscock

Department of Conservation, Southern Islands Area Office, Invercargill, New Zealand

The majority of crested penguin populations around the world are in decline. On Campbell Island the rockhopper penguin (Eudyptes chrysocome) has declined 94% since the 1940s. The Antipodes Islands supports approximately 65% of the world's population of erect-crested penguins (Eudyptes sclateri), and a population of rockhopper penguins. To date, census methods have differed, resulting in incomparable results; however, from scant data available it appears that colonies of both erect-crested and rockhopper penguins have declined on the Antipodes Islands. The main objective of the 2011 expedition to the Antipodes Island was to standardise survey methods and obtain accurate baseline survey data of the population size for the rockhopper and erect-crested penguins on the island. Several methods were used to enable comparison with previous data. The colonies are often of mixed assemblages of erect crested and rockhopper penguins, each nesting in slightly different habitat. Therefore it was necessary to conduct ground counts to get accurate census data for these species. Approximately 86% of the total estimated nests on the island were ground counted. Due to difficulty of access, the remainder were counted using binoculars from vantage points on the island or from a boat. A total Antipodes Island census of breeding penguins was obtained from this data. All penguin colonies were mapped in 1978 and 1989, and the 2011 expedition also repeated this survey to investigate the persistence of colonies over time.

Migration/egg formation overlap as an explanation of extreme egg-size dimorphism in Eudyptes penguins: a test in eastern rockhopper penguins on Campbell Island

K Morrison

Ecology Group PN 624, Institute of Natural Resources, Massey University, Palmerston North, New Zealand

Penguins of the genus Eudyptes are unique among birds in that their first-laid A-egg is 56–84% the mass of the second-laid B-egg. Although the degree of egg-size dimorphism varies among the seven species of the genus, obligate brood reduction is typical of each, with most fledged chicks resulting from the larger B-egg. Many authors have speculated upon why Eudyptes penguins have maintained a two-egg clutch, and why it is the first-laid egg which is so much smaller than the second, without producing robust hypotheses. After Eudyptes penguins return from their wintering grounds they fast at their nest sites between arrival and laying (the pre-laying period). A recent study of macaroni penguins (Eudyptes chrysolophus), a species with extremely size-dimorphic eggs, has shown that the degree of egg-size dimorphism of individual females is inversely correlated with the duration of their pre-laying period. In other words, females with a greater overlap between egg formation and migration lay more dimorphic eggs, suggesting a physiological conflict. The authors argued their result supported the hypothesis that extreme egg-size dimorphism in Eudyptes penguins results from a physiological constraint imposed by a migratory carryover effect, but this hypothesis has yet to be examined in any other species. I tested the ‘migration carryover effect’ hypothesis in eastern rockhopper penguins (Eudyptes chrysocome filholi) on Campbell Island, New Zealand, by recording the arrival and laying dates, and egg masses of transponder-tagged females. On average, female rockhopper penguins had a pre-laying period four days longer than that of macaroni penguins, a result congruent with the lesser degree of egg-size dimorphism of rockhopper penguins. Also in agreement with the hypothesis, I found an inverse relationship between the degree of egg-size dimorphism and the duration of the pre-laying period. Female arrival date was negatively correlated with the duration of the pre-laying period, in agreement with previous studies which found that female penguins adjusted their timing of laying towards synchrony with conspecifics. These results support the ‘migration carryover effect’ hypothesis, but suggest that individual variation in the duration of the egg formation period may contribute to individual variation in the degree of egg-size dimorphism in Eudyptes penguins.

Stress and the measurement of stress in penguins

J Cockrem^a, M Potter^b and P Barrett^b

^a Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand; ^b Institute of Natural Resources, Massey University, Palmerston North, New Zealand

Responses of birds to stressors involve the secretion of corticosterone, a glucocorticoid hormone that increases blood glucose and has other actions that help birds adjust to the stressors. We have investigated corticosterone responses in Adélie (Pygoscelis adeliae) and emperor penguins (Aptenodytes forsteri) in Antarctica to determine how the penguins respond to natural and artificial stressors, and to understand the significance of these responses for individual penguins. Adélie and emperor penguins both had clear corticosterone responses to capture and handling, whereas the approach of a person initiated corticosterone responses in some but not all Adélie penguins when a person stood 1 m from a nesting penguin. The approach of a person is not therefore necessarily a stressor for Adélie penguins. Corticosterone increased in emperor penguins when they were held temporarily in a pen or were followed, indicating that the birds perceived confinement or being followed to be stressors. Corticosterone responses to confinement and being followed were of similar magnitude to corticosterone responses to capture and handling. There were marked individual differences in corticosterone responses to capture and handling in both species of penguins. When corticosterone responses were measured on three occasions in Adélie penguins, relatively low or high responses were generally repeatable in individual birds. These individual differences in corticosterone responses may be associated with differences in breeding success and survival for Antarctic penguins.

Are transponders a suitable alternative to bands for the individual identification of yellow-eyed penguins?

D McFarlane

Yellow-eyed Penguin Trust, Dunedin, New Zealand

The individual marking of birds with bands is a long standing technique that has generated much valuable information about aspects of life history such as survival, recruitment and breeding behaviour. Penguin banding originated in 1908, with Louis Gain applying tarsus or leg bands to gentoo penguins (Pygoscelis papua papua). Lance Richdale began marking yellow-eyed penguins (Megadyptes antipodes) in 1936, utilising leg rings. The first flipper banding of yellow-eyed penguins dates from 1973 when Alan Wright (NZ Wildlife Service) banded fledging chicks at Penguin Beach, Otago Peninsula (first band J-1053). While banding has contributed enormously to our understanding of penguins, as a technique it has also attracted growing criticism and generated vigorous debate in the scientific literature, culminating in a 2011 paper (Saraux 2011) detailing adverse effects of banding on king penguins (Aptenodytes patagonicus). This paper attracted international attention in the news media. It is well recognised that flipper bands on yellow-eyed penguins require regular maintenance and can cause feather wear and tissue damage. Bands may also potentially affect foraging and reduce survival. The effect of bands on yellow-eyed penguins was the subject of a presentation by Yolanda van Heezik at the 2005 Oamaru Penguin Symposium; here the issue of alternative forms of individual identification was raised. Transpondering of yellow-eyed penguins, utilising a passive, individually encoded, glass-encased tag (PIT), was trialled by Brent Beaven (Department of Conservation) and the Yellow-eyed Penguin Trust on Stewart Island (from 2005–2006), and is now widely used by the Yellow-eyed Penguin Trust in its reserves. The Yellow-eyed Penguin Trust believes that transpondering offers a suitable and safer alternative to bands; however, a transition from flipper bands to transponders must be well co-ordinated to avoid data loss from key marked populations.

Use of transponders to monitor yellow-eyed penguins: updating best practice

B McKinlay^a, M Young^a and D McFarlane^b

^a Department of Conservation, Dunedin, New Zealand; ^b Yellow-eyed Penguin Trust, Dunedin, New Zealand

Since first being developed by Brent Beaven, the yellow-eyed penguin (YEP; Megadyptes antipodes) transponder best practice has been used for three seasons as the underpinning resource when marking YEP on the Otago coast. A review earlier this year was conducted. It incorporated feedback from users and evaluation of experiences. This presentation discusses these changes and implications for practitioners in the field. It is expected that the future will see more use of transponders, and so an emphasis on soft skills and an ability to work with YEP are required.

Decline in yellow-eyed penguin numbers on Codfish Island/Whenua Hou

D Houston^a and D Nelson^b

^a Department of Conservation, National Office, Auckland, New Zealand; ^b Department of Conservation, Twizel Area Office, New Zealand

A census of yellow-eyed penguin (Megadyptes antipodes) breeding pairs on Codfish Island/Whenua Hou was carried out on behalf of the Yellow-eyed Penguin Trust in October/November 2011. Five days of searching revealed 39 active nests, a 15% decline on the 2009 census (46 nests) and a 36% decline on the 2001 census (61 nests). All three main nesting areas experienced decline, with the Penguin Bay area being most affected. A reduction in the mean distance of nests to the coast was also noted. Recruitment failure due to poor juvenile survival is suspected to be the most significant cause of decline, but other factors, such as fisheries bycatch of adults, cannot be discounted.

A case of who moults together breeds together? A relationship between moult and divorce in yellow-eyed penguins (Megadyptes antipodes)

H Ratz^a and C Lalas^b

^a Penguin Place Conservation Reserve, Dunedin, New Zealand; ^b Box 31, Portobello, Dunedin, New Zealand

Breeding success did not improve following divorce by yellow-eyed penguins (Megadyptes antipodes) through 15 years from 1997/98 to 2011/12 at two adjacent colonies, Pipikaretu Beach and Ryans Beach on Otago Peninsula, South Island, New Zealand. Therefore there must be a major reason for divorce unrelated to breeding performance. Adult yellow-eyed penguins are sedentary and breeders have the opportunity to be in continual contact ashore with their mates between breeding seasons. The annual moult occurs between breeding seasons and so we investigated the role of this event as an indicator of mate retention. Breeders moulted either together with their mate from the previous season (synchronised moult with a temporal and spatial overlap) or apart from their mate from the previous season (asynchronised moult with either no temporal overlap and/or no spatial overlap). In the next breeding season the breeders either retained the same mate (unchanged pair) or divorced (both mates were alive but did not breed with each other). Breeders from unchanged pairs were more likely to have moulted together with their mates than breeders which divorced. Spatial synchrony (moult at the same site) was a more important indicator of future mate fidelity than temporal synchrony (moult at the same time). Consequently, pairs are more likely to stay together if mates find each other during the moult, regardless of any differences in their timing of the moult. This outcome has an implication in the conservation management of the species: human disturbance of moulting penguins may disrupt pair bonds.

Lifetime reproductive success in yellow-eyed penguins: influence of life-history parameters and investigator disturbance

A Stein, Y van Heezik and P Seddon

Zoology Department, University of Otago, Dunedin, New Zealand

Longitudinal studies focusing on lifetime reproductive success (LRS) can be used to measure individual breeding performance, and identify commonalities amongst successful breeders. In yellow-eyed penguins (Megadyptes antipodes), although certain characteristics indicative of poor breeders are known, there has not yet been a comprehensive study of the components influencing LRS. In a well-studied species, the question arises whether intensive research and monitoring is negatively affecting LRS. Yellow-eyed penguins are known to be vulnerable to human intrusion, and research on this species often warrants the need for handling of birds, eggs and their young. The aim of this study was to analyse 23 years of yellow-eyed penguin breeding data to determine which life-history components, including investigator disturbance, influence LRS in yellow-eyed penguins on the Otago Peninsula, New Zealand. Effects of investigator disturbance were also measured for probability of yearly breeding success and adult survival. In total, 18.8% of yellow-eyed penguin chicks survived to breed, and 10.3% produced offspring that were subsequently banded before fledging. Despite the high juvenile mortality rate of yellow-eyed penguins, the birds that do attempt breeding have high success rates in comparison with other seabird species. The main factors affecting LRS were lifespan, breeding lifespan and age at first breeding. There were no strong effects of investigator disturbance on LRS, probability of breeding success, or adult survival. However, instances of investigator disturbance may affect LRS by artificially reducing the lifespan of birds subjected to intensive regimes of blood sampling and double-banding. This result was found for blood sampling in one of three breeding seasons, and for double-banding in one of two breeding seasons. While there were some limitations associated with adopting a retrospective approach, the longitudinal aspect of this study identified variation in results between breeding seasons, possibly due to random effects such as the stochastic nature of the marine environment and predation.

Impact of commercial fisheries on yellow-eyed penguins: what we know and what we need to know for a sound risk assessment

U Ellenberg and T Mattern

Eudyptes EcoConsulting Ltd, Dunedin, New Zealand

The yellow-eyed penguin (Megadyptes antipodes) is endemic to New Zealand, and is one of two penguin species with the most fragile conservation status on the planet. It is a long-lived species and population viability analysis shows that even a small increase in adult mortality augments extinction probability dramatically. The yellow-eyed penguin population on the New Zealand mainland, including Stewart Island, is small (600–800 breeding pairs). Previous population strongholds, such as on the Otago Peninsula, are declining. Since the mainland population is genetically distinct from sub-Antarctic populations (inferred immigration rate 0.003 per generation) the current loss of yellow-eyed penguins along the southeast coast of the New Zealand South Island and in the Foveaux Strait will not be compensated by immigration. Fisheries bycatch may be substantial, particularly in the commercial set net fisheries. Historically, observer coverage of the inshore fishing fleet has been low (c. 2%) and erratic. Despite recent efforts to increase independent observer coverage it remains highly spatially and temporarily focused and high risk areas for yellow-eyed penguin bycatch have not yet been included into the observer programme. The observed bycatch likely underestimates true numbers substantially. Since there is little incentive for fishermen to report entanglements, the majority of incidents remain unreported. The information currently available does not allow assessment of the full extent of the fisheries’ impact. We have been contracted by the Conservation Services Programme (CSP), Department of Conservation, to review and collate information existing to date on yellow-eyed penguin population parameters. Important gaps in our knowledge have been identified and we provide recommendations for future research in order to better assess the direct and indirect effects of commercial fisheries on yellow-eyed penguins. This report will be available on the CSP website: http://www.doc.govt.nz/publications/conservation/marine-and-coastal/conservation-services-programme/. Most importantly we need to increase independent observer coverage on commercial set net and inshore trawl fisheries that operate within foraging areas of yellow-eyed penguins in order to quantify numbers caught and document operational details affecting the likelihood of capture. Since bycatch rates are likely to be low, independent observer coverage needs to be high to achieve reasonable precision in bycatch estimates. Electronic monitoring can supplement independent observers allowing better overall coverage while keeping the related costs manageable. Such data are essential for the development of mitigation measures or temporal/ spatial management to reduce yellow-eyed penguin bycatch in the commercial fisheries.

What the demographics of tawaki tell us about its population trend and what conservation efforts would be most effective

H Otley^a and P Scofield^b

^a West Coast Tai Poutini Conservancy, Department of Conservation, West Coast, New Zealand; ^b Canterbury Museum, Christchurch, New Zealand

In 1994, the Department of Conservation commenced a demographic study of the nationally vulnerable Fiordland crested penguin (tawaki, Eudyptes pachyrhynchus) on the West Coast. Each year until 2005, both prior to breeding commencing and before chicks fledged, all penguins present at two sites were captured and equipped with, or checked for, flipper bands and/or microchips. Both study sites were also surveyed for tagged birds in July 2010. Eight hundred and sixty birds were tagged, and recapture events included live and dead birds at both study sites and at other beaches on the West Coast, with dead birds also found at other sites in New Zealand as well as Australia. The mark-recapture analysis indicated that the apparent survival of birds was around 0.85, with 0.83 for banded birds and 0.88 for birds with a transponder only. Using the calculated adult survivorship and age of first breeding of known-age banded birds, together with the breeding success rates calculated through the annual nest and chick counts at three sites on the West Coast between 1988 and 2009, it was possible to model the population trend. As we did not know the survival rates of juvenile tawaki, we used the rate calculated for the congener macaroni penguin studied at South Georgia. The matrix model indicated an annual rate of decrease of 0.07. The rate of decline indicated by the demographics of tawaki means that the species could be re-assessed as critically endangered and at least should be considered as nationally critical. The Department of Conservation has considered the results of the nest counts and population modelling and agreed a new work plan for the species. Although the results of the population modelling indicated that adult survival has the most influence on the population trend, it also demonstrates that an increase in breeding success would produce a slower rate of decline. Thus, the work plan aims to reduce adult deaths and reduce rates of predation of eggs and chicks.

Tawaki recovery update

H Edmonds

Department of Conservation, Te Anau Area Office, New Zealand

Fiordland crested penguins or tawaki (Eudyptes pachyrhynchus) are a nationally vulnerable species, restricted to the coastlines of Stewart Island and surrounding islands, Solander Island, Fiordland and South Westland. Nest counts at sites in South Westland, Fiordland and on Codfish Island have been conducted by the Department of Conservation (DOC) over several years, and results show an overall decline in the population. At the Oamaru Penguin Symposium in 2010, staff directly involved in tawaki monitoring presented results, highlighted concerns about data accuracy, and discussed plans to design and test a more accurate dual nest count method. The ensuing discussion created support and technical advice allowing a more formalised group to continue with tawaki recovery. Since 2010 the dual nest count method has been tried and tested throughout two breeding seasons and an initial analysis indicates we have 95% confidence of detecting an 11% change in the number of nests between years. During the first year of the method, some nest desertion was experienced at some of the sites—up to 10% at Codfish Island. Concerns led to a project investigating this in 2011, results of which will be presented at this symposium. Several other advances in tawaki recovery have been made over the last 2 years. A survey was conducted during 2010 and 2011 to count tawaki nests on Solander Island. The results detected a 44% decline from 1993 to 2011. Plans are to survey the island for the next 3 years, to account for yearly fluctuations in numbers to achieve an accurate picture of the population trend. A draft 5-year work plan for tawaki was written by Helen Otley (formerly from DOC Hokitika) in January 2012. The plan lists goals and prioritises actions to achieve these. There was a chance to advocate for the plight of tawaki following media coverage surrounding Happy Feet, and a feature article appeared in the Southland Times, which in turn generated an interview with Jim Mora on Radio New Zealand.

Future plans are to:

•	Improve and finalise the 5-year work plan
•	Continue with the double count monitoring technique
•	Improve information on population size and trends—with plans to re-survey coastlines counted by McLean et al. (1997)
•	Seek advocacy and funding opportunities for Fiordland crested penguins.

Assessing the effects of nest searches on Fiordland crested penguins

U Ellenberg^a, J Hiscock^b, R Wilson^c, H Edmonds^d and E Edwards^e

^a Eudyptes EcoConsulting Ltd, Dunedin, New Zealand; ^b Department of Conservation, Southern Islands Area Office, Invercargill, New Zealand; ^c Department of Conservation, South Westland, Weheka Area Office, Haast, New Zealand; ^d Department of Conservation, Te Anau Area Office, New Zealand; ^e Department of Conservation, Southland Conservancy, Invercargill, New Zealand

Fiordland crested penguins (Eudyptes pachyrhynchus) nest in loose colonies in difficult terrain; thus, single nest counts will almost always yield an underestimate of true nest numbers with no means to determine potential error. Double counts by two independent teams with similar experience and effort allow quantifying the number of nests missed during a single search and thus will provide a better estimate of actual nest numbers. A pilot study using double counts during the 2010 breeding season suggested that even a single nest count may have considerable impact on incubating Fiordland crested penguins, with up to 12% of the nests found abandoned during the second search. Hence, concern has been raised that the higher accuracy of double counts may come at the cost of higher nest failure rates. In the course of nest searches during the 2011 breeding season we recorded disturbance responses of nesting birds and nest habitat details. Additionally, a small thermosensor (iButton) was slipped into a selection of nests while checking nest contents in order to quantify how long the clutch was left unattended and if the nest remained active after the second search. iButtons were retrieved at the end of the season after the birds had left their breeding sites. Only five (1.9%) of the 258 nests re-sighted during second searches had definitely failed. Another four presumed nests were found empty during the second search; however, these had not been confirmed active (i.e. containing eggs during the first search). Three of the failed nests contained iButtons and temperature data showed that two nests likely failed due to search disturbance while one nest was permanently abandoned 4 hours after the searchers had left the area. iButton temperature data available from 57 nests suggest that three nests (5.3%) likely failed during the second search day. However, for only one of these nests (1.9%), were nest record data sufficient to relate the abandonment to search activity. Given the overall low nest failure rates observed in 2011 we conclude that the use of double counts may be acceptable to quantify breeding pair numbers of Fiordland crested penguins. However, we need more data on the causes of temporary and permanent nest abandonment in order to better understand the higher nest failure rates observed in 2010. A comprehensive set of data (iButton data, nest records and GPS tracks of searchers) will facilitate the development of recommendations on how to minimise disturbance effects associated with nest searches in Fiordland crested penguins.

Captive management of little penguins during the 2011 Rena oil spill

B White and P Conayne

New Zealand Wildlife Health Centre, Massey University, Palmerston North, New Zealand

In the event of an oil spill in New Zealand, the New Zealand Wildlife Health Centre has a contractual agreement with Maritime New Zealand to manage the oiled wildlife response. In 2011 New Zealand suffered its worst environmental disaster to date. On 5 October the C/V Rena ran aground on the Astrolabe Reef, Tauranga, and consequently spilt over 300 tonnes of heavy fuel oil. The little penguin (Eudyptula minor) was the most common affected species found oiled but alive during the Rena oil spill incident, with over 400 penguins admitted with varying degrees of oiling. The wildlife facility also admitted several other species including pied shags (Phalacrocorax varius), Australasian gannets (Morus serrator) and diving petrels (Pelecanoides urinatrix urinatrix). Little penguins are found commonly around the coast of New Zealand and the southern coast of Australia. It is the world's smallest penguin, weighing between 800–1000 g and with a height of only 25–30 cm, but is a tough character. The peak egg-laying season for little penguins is from September to November with chicks taking 8 weeks to fledge. The spill coincided with egg-laying and decisions had to be made regarding the practicality and probability of success with taking in and raising chicks during this time. Previous experience suggested that hand-raising little penguin chicks has minimal success in producing individuals fit for wild release due to imprinting. Therefore, a collective decision was made to euthanise any chicks brought into the facility. The oiled penguins’ lifecycle was disrupted and we feared there was a high probability of an early moult. Moult usually occurs between December and March. An early moult did not occur and it is likely either that the stresses of captivity delayed the onset of moult or that the period for moulting is inflexible in these penguins. Previous experience with little penguins in captivity shows that pododermatitis and aspergillosis were the two most likely problems to occur. To prevent aspergillosis, itraconazole was used prophylactically at 5 mg/kg once a day, given orally to all penguins, and there were no confirmed cases of aspergillosis seen in penguins throughout the spill, although other species died with this disease. The husbandry requirements for the birds were fluid and evolving throughout the spill and compromises on materials or designs resulted in preventable problems. Fruit crates were used to house the penguins in the oiled and just-cleaned phases. The penguins were then moved into purpose-built outdoor aviaries. Different materials were used to create a net bottom cage in the fruit bins whereas tube tread matting was used in the aviaries. Compromising on quality of flooring in the aviaries for cost was soon regretted and later rectified. Pododermatitis was also prevented or reduced by increasing the forced swim time for the birds.

Little penguin rehabilitation cases from the Tasman region

M Stratton

Gardner Valley Road, Upper Moutere, New Zealand

Pixie was a two-day-old little penguin (Eudyptula minor) chick when brought into care, having been found by some children. There was concern that at such a young age Pixie would imprint while being hand-raised. Information from Australia indicated this would not be a problem, but evidence in New Zealand suggested otherwise. A number of precautions were taken to minimise Pixie's risk of imprinting and increase the chance of being able to fledge into the wild. Fred was one of many penguins to turn up as an underweight, starving, fledging in the summer of 2010–2011, a lesser number came in during the summer of 2011–2012. These penguins were found to have been eating anything they could find, including twigs and grass. They were also covered in ticks. Fred showed signs that were suggestive of tick paralysis. Identification of the ticks (Ixodes eudyptidis Maskell) confirmed it does cause paralysis in birds but they generally recover on removal of the ticks. In October 2011 a dog attack on a determined little penguin trying to guard its nest left it dead and its mate and two chicks at risk of not surviving. The remaining adult penguin, thought to be the female as she was smaller than the killed penguin, was brought into care with her two chicks. Amazingly, the adult penguin remained very dedicated to her chicks while in captivity. Scientific research done in Australia on little penguins backed up the behaviour observed in captivity as normal. This all helped in allowing this little penguin to successfully raise her two chicks in captivity and then be released back to the wild with them.

Can mixing models be used to detect dietary shifts in seabirds?: isotope so

S Flemming and Y van Heezik

Zoology Department, University of Otago, Dunedin, New Zealand

Many seabird populations are in decline due to shifts in food quality and availability, which can affect reproductive performance. Dietary monitoring can be used to relate population fluctuations to at-sea events. Stomach flushing is a conventional dietary monitoring technique, but is biased and may be intrusive. Stable isotope analysis (SIA) is a less invasive method that provides dietary information over a longer period, but its effectiveness has not been determined in areas with unique prey compositions. Our objective was to evaluate SIA as a potential dietary monitoring technique by determining the effectiveness of SIA at detecting differences in prey composition between three little penguin (Eudyptula minor) colonies. Isotopic mixing models (IMMs) were created for blood and feathers at each colony and compared to results from stomach contents analysis (SCA). SIA of blood and feathers detected differences in δ15N and δ13C between colonies, indicating differences in trophic level and feeding area. Broad-scale (fish, cephalopods, crustaceans), feather and blood IMMs predicted different proportional contributions of prey items to diet than indicated by stomach samples, possibly reflecting the different temporal periods and biases associated with each method. Fine-scale (different species) IMMs predicted proportional contributions of prey items with less certainty than broad-scale IMMs. Blood IMMs had narrower confidence internals and were therefore more certain of prey composition than models for feathers. SIA could be used to detect shifts in the consumption of broad taxa, which can have negative impacts on seabird populations, but they may be less useful in discriminating between species.

Monitoring little penguins on Matiu/Somes Island, Wellington Harbour

R Cotter

Ornithological Society of New Zealand, Wellington, New Zealand

The end has arrived on a 5-year study on the effects of metal flipper-bands on little penguins (Eudyptula minor) on Matiu/Somes Island, which we began in 2007. There was a concern the presence of bands may affect the survival of little penguins by reducing their swimming speed, reputedly by up to 20%. I have been involved in banding studies of little penguin on Matiu/Somes since 1975 with the late Dr Fred Kinsky of the National Museum, now Te Papa. For the present study we first searched the island (25.9 ha) for nest sites. Also two offshore islands Mokopuna (Leper) and Mākaro (Ward) were searched and sites recorded. Matiu/Somes Island is naturally divided into different areas by walking tracks and natural ridges. We coded these areas by using their known names: North Point (N); Cable Bay (NP); Wharf Area (CB); etc. Nest sites were then numbered (e.g. NP1, NP2) in each area. For the penguin banding versus transponder study, only accessible nest sites were chosen, which covers about 60% of the breeding habitat on the island. We had made and installed 240 wooden nest boxes which were assembled by members of the Kiwi Conservation Club, and high school and college students. These were distributed in areas likely to be used by penguins and over many existing nest sites. We moved any boxes not used after 2 years to new sites. We had volunteers from Royal Forest & Bird, the Ornithological Society of New Zealand, Miro, Massey and Victoria University students, and many staff from Department of Conservation offices. Monitoring was done over a 3-day period, staying two nights, and was carried out monthly during the non-breeding period and fortnightly during the breeding season. All nightwork was carried out in the easily accessible wharf area, where a good number of birds came ashore, and along the shoreline near the Whare Kiore (Rat House). All penguins arriving ashore in the evening were captured and checked for bands, web tags and transponders. All new (unmarked) birds were tagged, measured, weighed and marked temporarily with non-toxic paint on the head. If these individuals were located again they would not be disturbed. During the day field teams checked all known nest sites and recorded the presence of penguins, chicks and/or eggs. Some interesting finds included a ‘mottled’ little penguin, several penguins with algae growing on them, birds with the appearance of white-flippered penguins (E. minor albosignata) and tuataras (Sphenodon punctatus) taking over penguin nest boxes.

Are we making them feel a little blue? Human disturbance and little penguins

S Larcombe

Department of Zoology, University of Otago, Dunedin, New Zealand

A major way of increasing the value of wildlife to the public is to allow the public access. This places increasing pressure on wildlife ventures to allow close contact with animals. However, the impacts of both tourist and researcher disturbance on wildlife are largely unknown. Sub-lethal physiological changes, such as increased heart rate and rate of oxygen consumption, may ultimately cause population-level effects by affecting the energy fraction available for essential processes and behaviours. The effects of human disturbance on penguins are known to be highly species-specific, so it is essential that they are determined for each species. This will enable any detrimental effects of human–penguin interactions to be minimised. Little penguins (Eudyptula minor) are considered relatively robust to human disturbance as they do not exhibit overt behavioural responses. However, physiological responses have not been quantified. My investigation seeks to determine the effects of both researcher and tourist disturbance on physiological parameters, namely heart rate and rate of oxygen consumption, of the inhabitants of the tourist-oriented little penguin colony at Oamaru, New Zealand. My investigation is divided into two components: researcher disturbance and tourist disturbance. To determine the effects of researcher disturbance, heart rate and rate of oxygen consumption of adult penguins will be recorded in relation to controlled disturbance events. To determine the effects of tourist disturbance, chick growth rates and adult heart rates will be related to the degree of impact tourists have on nests in different zones of the colony. The results of my investigation will be important for future management decisions at the Oamaru Blue Penguin Colony, as well as other little penguin colonies. Evidence that human disturbance is not having detrimental effects will be valuable to the Oamaru colony. Conversely, evidence that penguins are being negatively affected will prompt changes to address this.

Is seabird survival affected by wind? A mark-recapture analysis of little penguins (Eudyptula minor) in southeastern Australia

LM Ganendran^a, L Sidhu^a, E Catchpole^a, P Dann^b and L Chambers^c

^a School of Physical, Environmental and Mathematical Sciences, University of New South Wales Canberra, Australian Defence Force Academy, Canberra, Australia; ^b Research Group, Phillip Island Nature Parks, Cowes, Phillip Island, Australia; ^c Centre for Australian Weather and Climate Research, Bureau of Meteorology, Melbourne, Victoria, Australia

Wind from each of the four cardinal compass points has previously been shown to affect the survival of first-year and adult little penguins (Eudyptula minor). We found that southerly winds in the winter prior to a chick's birth are associated with increased annual survival probability in its first year of life, and easterly winds in the summer of hatching/fledging are linked with decreased survival. Adult survival is positively associated with increasing northerly winds in the autumn following moult, and negatively associated with easterly winds in the preceding summer. The lagged nature of these effects highlights the complexity of the mechanisms affecting survival. Here, using a mark-recapture analysis of a 42-year data set from Phillip Island, southeastern Australia, we investigate possible relationships between first-year penguin survival, wind strength and winds above different threshold values. The parameters of interest in this study, the survival and recapture probabilities, are given biologically sensible age and time structures. Likelihood contributions are formed from life history data, and maximum likelihood methods are then used to estimate the parameters. First-year survival is negatively correlated with severe westerly wind events in the autumn just after fledging. However, strong winds in the winter following fledging have a positive association with first-year survival. The mechanisms by which strong wind events affect first-year penguin survival are not yet fully understood, but are possibly linked to the movement of nutrient-rich waters into or out of the penguins’ foraging areas, or to the mixing of the water column, making prey acquisition more difficult.

Little penguins at the Kaikoura Peninsula

L Rowe

Margate Street, Kaikoura, New Zealand

Little penguins (Eudyptula minor) have been banded at the Kaikoura Peninsula since 2006. Over six seasons 158 birds have been banded, mostly in the vicinity of or under the coastguard building at South Bay, but several birds were caught on the north side of the Peninsula at two burrows (now unused) or moulting. Eighteen of the 96 adults banded were white-flippered (E. minor albosignata), two of which nested last season with little penguins. Sixty-two chicks have fledged, but this is an underestimate of the total produced as access is not available to about eight nest sites. One bird from Oamaru has taken residence and a mate.

Cars, dogs and mustelids: mortality of little penguins on the West Coast, South Island, New Zealand

KJ Wilson^a, R Lane^a, J Braidwood^b, A Columbus^c and I Davies^c

^a West Coast Blue Penguin Trust, Charleston, West Coast, New Zealand; ^b Ecology Department, Lincoln University, Lincoln, New Zealand; ^c Department of Conservation, Franz Josef Waiau Area Office, Franz Josef, New Zealand

The West Coast Blue Penguin Trust was formed by local people concerned by the apparent decline in little penguin (Eudyptula minor) numbers. Since starting the Trust we have maintained a penguin mortality database which records the date, location and cause of death of all dead penguins handed to the Trust or the Department of Conservation. We have monitored breeding success in little penguin colonies with, and colonies with no, mustelid control for 4 years at colonies near Charleston and 3 years at colonies in South Westland. Predation by introduced mustelids is a major cause of breeding failure in white-flippered penguins (E. minor albosignata) on Banks Peninsula and has either been shown to be, or assumed to be, an important cause of breeding failure in little penguins elsewhere in New Zealand. However, we have found no significant differences in breeding success between colonies with or without mustelid control in any breeding season at either area. Our penguin mortality database has shown roadkills and dogs to be the most significant mortality factor for West Coast little penguins, with most deaths being of adult penguins, which has a greater impact on population viability than breeding failure. In 2012, in collaboration with Transit New Zealand, one colony was fenced to prevent penguins gaining access to the road. If this successfully reduces roadkill we will fence further roadside colonies.

Seasonal variation in diving behaviour of little penguins

P Agnew

Department of Marine Science, University of Otago, Dunedin, New Zealand

Little penguins (Eudyptula minor) are highly adaptable to fluctuations in the marine environment. At Oamaru, the onset of egg-laying varies every year and can occur from as early as May to as late as September. This adaptability indicates that the penguins are able to adjust their breeding behaviour to cope with intra- and inter-seasonal variation in food availability. The objective of the present study was to determine how the diving behaviour of little penguins relates to changes throughout the breeding season; both in terms of varying reproductive demands at different stages of the breeding cycle and fluctuations in the environment. The objective was also to investigate differences in diving behaviour between seasons. Time-depth recorders (TDR) were attached to little penguins during the pre-egg, incubation and chick-guard stages of the 2010 and 2011 breeding seasons at Oamaru. The use of TDR devices generates an extremely large dataset, providing a number of variables that can be used to infer patterns of diving behaviour. The relevance of different dive variables is discussed and results presented.