Interactions between kororā/little penguins (Eudyptula minor) and their terrestrial environment at Pōhatu/Flea Bay, Banks Peninsula.

Abstract

The kororā/little penguin (Eudyptula minor) is a seabird found across New Zealand and Southern Australia and is an important biological indicator of ecosystem health. Despite what the term ‘seabird’ suggests, kororā rely heavily on their terrestrial habitat for nesting and breeding. As a result, these birds may select particular breeding sites and exhibit movements across multiple temporal scales that could enhance reproductive success and survival. However, breeding habitat selection, breeding success, and movement patterns can differ across colonies due to varying threat and habitat contexts, necessitating local-scale research. In this thesis I explored the breeding ecology and movement dynamics of kororā at the Pōhatu/Flea Bay colony on Banks Peninsula, New Zealand, using weekly monitoring data from two breeding seasons (2022 and 2023). In chapter 2, using a combination of generalised linear models and occupancy models, I aimed to investigate how fine-scale habitat and nest box characteristics influence nest box selection for breeding and hard tick presence (Ixodes eudyptidis). Additionally, I examined whether these characteristics, along with lay timing and tick presence, impact breeding success. In chapter 3, I used generalised linear models and qualitative descriptions to explore the interannual and weekly-scale movements of 92 microchipped individuals, looking specifically at nest box and mate fidelity, natal nest box philopatry, and the influence of behavioural stage on weekly movements. My findings revealed that kororā selected more isolated nest boxes for breeding, with an indication that they may be less likely to breed in newer nest boxes, which also had lower tick presence. However, I found that breeding success was primarily influenced by lay timing, with later lay dates reducing hatching success in both years and sharply decreasing fledging success in 2022, whereas fledging success remained higher in 2023. High nest box fidelity was observed between the two seasons, with 81% of returning breeders using the same nest box, where prior hatching success was found to influence those that changed nest boxes. Partner fidelity was also high, with 91% of pairs observed together in 2022 remaining together. At a weekly scale, 28% of individuals were observed at more than two different nest boxes across the study period, with movements ranging from neighbouring nest boxes (<1 m) to distant boxes (up to 335 m), and these movements predominantly occurring during loafing (i.e. the period when individuals are not actively breeding or moulting). Together, these findings offer valuable colony-specific insights that can inform conservation efforts and serve as a foundation for ongoing research at Pōhatu, benefiting from additional years of data. Based on this information, I provide practical conservation applications, including recommendations for optimising nest box placement and design to improve their use for breeding and enhance nest fidelity, while highlighting the importance of integrating terrestrial and marine conservation efforts to improve breeding success