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    The time course of corticosterone responses in kororā (little penguin, Eudyptula minor) : a thesis presented in partial fulfilment of the requirements of the degree of Master of Science in Zoology at Massey University
    (Massey University, 2017) Long, Kar Hui
    When birds and other vertebrates perceive a situation to be threatening the hypothalamopituitary-adrenal (HPA) axis is activated and glucocorticoid hormones are secreted from the adrenal gland. Activation of the HPA axis in response to a stimulus perceived to be threatening is called a stress response. The main glucocorticoid hormone in birds is corticosterone. Corticosterone responses of birds are typically measured by the collection of an initial blood sample when a bird is captured or picked up, then the collection of further blood samples until 30 to 60 minutes has elapsed, at which time the bird is released. Whilst this standard sampling protocol provides information on the size of the corticosterone response, it does not provide any indication of how long it takes for corticosterone concentrations to return to initial values. The main objective of this thesis was to characterise the total duration of the corticosterone response of free-living kororā (little penguins, Eudyptula minor). Little penguins at Oamaru were picked up from their nestboxes and initial blood samples collected. Birds were handled and then restrained by being placed in a box. Further blood samples were collected 15, 30 and 60 min after the birds were first picked up. Birds were then returned to their nest boxes and an additional blood sample collected 15, 30, 60, 120, 240, or 360 min later. Mean corticosterone concentrations declined to initial values two hours after birds were returned to nest boxes. The rates at which corticosterone concentrations increased when a stressor was present and then decreased when the stressor was no longer present were positively correlated. Seasonal changes in corticosterone responses in little penguins were also investigated in this study. Mean corticosterone responses were similar in winter and in the pre-laying period, whereas mean responses were lower in birds during early chick rearing. Corticosterone responses during the pre-laying period were greater in male than female little penguins. The current study is the first to document the complete corticosterone responses of free-living penguins and provides information about changes of corticosterone concentrations after a stressor is removed from the free-living individuals. It is also the first to reveal that free-living penguins with relatively high corticosterone responses to a stressor had relatively high rates of corticosterone decline.
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    The feeding and breeding ecology of little blue penguins (Eudyptula minor) from Tiritiri Matangi Island, New Zealand : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Conservation Ecology, Massey University
    (Massey University, 2006) Geurts, Jacqueline Lee
    At present the New Zealand populations of Little Blue Penguins (LBP: Eudyptula minor) are classified as 'Threatened' and in 'Gradual Decline' by the Department of Conservation. Effective conservation management of the North Island sub-species requires an understanding of the factors affecting their survival and breeding success. There is little information on the breeding ecology of the E. minor, especially in the North Island of New Zealand. The overall goal of this study was to establish baseline data on a North Island population of LBP in New Zealand. The aims of this study were to 1) identify population demographics, 2) quantify breeding success and identify abiotic and biotic parameters influencing nesting success, 3) identify feeding ecology based on diet and trophic level assessment, and 4) identify cause of death and underlying patterns associated with mass mortalities of the LBP species. Breeding success was quantified by monitoring the nesting activity of 87 nesting attempts during the 2005/06 breeding season. Nest monitoring also involved identifying risks associated with both the egg and chick stage. Diet analysis involved comparing stomach regurgitation samples and isotope samples of feathers spanning a 120 year period. The cause of death for the mass occurrence of beach wrecked birds found during 2005/06 was established through necropsies and histological tests. The major cause of death was compared to patterns of past beach wreck events that has occurred in New Zealand over a 33 year period, obtained through the Ornithological Society of New Zealand. Where possible, both short- and long-term comparisons were made to establish a sound understanding of the key factors that are influencing breeding success, foraging, and survival. Results showed that 2005/06 was a poor breeding year which was the result of a large number of nest desertions. Furthermore, analysis of stable isotopes shows that the LBP have been feeding at low trophic levels over the past 120 years and that 2005 was significantly lower in carbon levels suggesting a low year of marine productivity. The largest cause of death associated with mass beach wrecks was starvation. Analysis of past beach wrecks suggest that during the year LBP are at a greater risk of death after the breeding season, after moult, and during winter which are energetically expensive periods. A more long-term study is required to identify the trends in LBP breeding success and to ascertain the primary reason as to why they are unable to obtain enough food. Seabirds are increasingly being used as biological indicators since they are largely influenced by changes associated with the marine environment. The use of LBP as biological indicators may have limitations depending on the parameters being used. However stable isotope measures may be one of the easiest methods to achieve this and allows for reconstruction of past ecological histories through analysis of historical tissues.
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    The foraging ecology of Little Penguin (Eudyptula minor) on Tiritiri Matangi Island : a thesis submitted in partial fulfilment of the requirements of Master of Science in Conservation Biology, Massey University, Auckland
    (Massey University, 2011) McKenzie, Fiona Rea Katrine
    Little Penguins (Eudyptula minor) are the smallest penguin in the world. They have a distribution ranging from south-western Australia, through to New Zealand and the Chatham Islands. Some populations in Australia and the South Island of New Zealand have been the subject of considerable research, but there has been less undertaken on populations in the northern half of New Zealand. The Department of Conservation however, are concerned about their status and have list the northern populations as ‘At Risk – Declining’ in the New Zealand Thread Classification System. As part of a new longitudinal study on Little Penguins (LP) resident on Tiritiri Matangi Island, Hauraki Gulf, New Zealand this study focussed on their foraging behaviour and breeding success over 2010 and 2011. Two new biogeochemical techniques were used in this study to examine LP diet from tissue samples. Stable isotope analysis of LP blood, feathers and potential prey species established the trophic level of the LP (calibrated from a captive feeding trial) and was able to determine both temporal and spatial shifts in trophic level over a 12 month period. These shifts may indicate changes in prey type or abundance, however more research is required to determine this. Fatty acid signature analysis of potential prey and LP adipose found similarities that suggest the prey types were likely included in the LP diet, but sample sizes were small and again further research is required. Abundance of potential prey species within the local Hauraki Gulf region were extrapolated from commercial catches of bait fish statistics and foraging ranges from were proxied from previous studies. It was determined that commercial fishing is unlikely to impact the LP at this time. A third emerging technology, GPS tracking dataloggers, was proposed to track the penguins across the breeding and non-breeding seasons to determine where they foraged, how far they ranged and how this changed seasonally. Unfortunately, equipment failures resulted in no tracks being recorded. Breeding success recorded for 5 years was extremely variable however, for one year at least, it was apparent that a significant absence of preferred prey may be linked to a devastatingly poor year for rearing chicks. Top predators such as seabirds, including penguins, are a model bioindicator for the health of their local marine environment i.e. a seabird population that breeds well and is in good body condition likely indicates there is abundant food and clean water. Conversely a sea bird population that is declining in size or experiences poor recruitment, may be an indication that prey is absent or that waters are polluted. With the local North Island LP populations potentially already in decline, it is important to continue to monitor aspects of their breeding and foraging in the coming years – not only for the benefit of the penguins, but for the wider conservation of the Hauraki Gulf Marine Park.
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    The effect of conservation management on Little Blue Penguins (Eudyptula minor) on North Island, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Conservation Biology at Massey University, Auckland, New Zealand
    (Massey University, 2009) Lowe, Mark Ian
    This study aimed to fill a gap in research, particularly on the size of breeding populations of Little Blue Penguins in the North Auckland area, while also providing recommendations for the conservation management of Little Blue Penguins. Three sites North of Auckland were used for the majority of this study; Tawharanui North, Tawharanui South and Goat Island The abundance and nest density of Little Blue Penguins was estimated for the three sites north of Auckland. All three sites had a very low nest density: 0.0096 nests/100m2 at Goat Island, 0.0064 nests/100m2 at Tawharanui North and 0.0048 nests/100m2 at Tawharanui South. Abundance showed a similar trend, with Goat Island having the highest average number of birds coming ashore over the year (2.25 birds per night), followed by Tawharanui North (1.81 birds per night) and finally Tawharanui South (1.19 birds per night). Habitat surveys were conducted at the three sites and differences in habitat structure were found between all three. Tawharanui North was predominantly sand and flax and Tawharanui South was predominantly pebbles and scrub, while Goat Island displayed mostly sand with no vegetation. The results suggested that grass and boulders make up the Little Blue Penguins‘ preferred nesting habitat and it was predicted that sites containing more of this habitat type would have higher nest densities and abundance, although small sample sizes prevented this from being validated statistically. The nest success was calculated, again for the three sites, using the Mayfield method. The key results showed that the incubation period was associated with the lowest success rate of any of the nesting stages observed. Success rates for the incubation stage at the three sites fell between 0.11 and 0.66, success rates for the guard stage fell between 0.74 and 1.00, and success rates for the post-guard stage fell between 0.62 and 1.00. Findings also revealed that nest success was greater at the two Tawharanui sites (where similar rates of nest success were observed) than at the Goat Island site The number of carcasses recovered was recorded as follows: Goat Island, 0.67 birds/km; Tawharanui North, 0.63 birds/km; and Tawharanui South, 0.43 birds/km. There was no statistically significant difference between the rates of carcass recovery and the study site, nor was there a statistically significant difference between the rates of carcass recovery and the season. The rates of carcass recovery were also determined to be lower than historically found for these sites. As an aside to the rest of this study the acute stress response of Little Blue Penguins to pit tag and metal flipper band application was assessed through measuring corticosterone levels in the blood of the birds. The results showed that implantation of a pit tag produced a significantly greater acute stress response than banding with the traditional metal flipper bands. This study makes recommendations regarding the study and conservation of Little Blue Penguins. These recommendations are found throughout this thesis; however, key recommendations are repeated here for convenience.  Re-assess density and abundance measures for the Tawharanui and Goat Island sites in 5 to 10 years time  Research what makes a particular habitat type more preferable than another for Little Blue Penguins  Place nesting boxes around the Tawharanui coast to increase suitable nesting habitat  Carry out ongoing carcass recovery observations and necropsies on penguin populations in Auckland to better understand the causes of mortality  Engage in further study regarding both the acute and chronic stress levels induced by different identification techniques  Engage in further study into possible alternatives to both pit tags and metal bands for penguin identification  Protect Little Blue Penguins from predators on the mainland where possible