Browsing by Author "Elsom, Henry"

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    The foraging behaviour and range of little penguins (Eudyptula minor) at two neighbouring colonies : a thesis presented in partial fulfilment of the requirements of the degree of Master of Science in Conservation Biology at Massey University, New Zealand
    (Massey University, 2022) Elsom, Henry
    Differences between colonies in foraging behaviour have been reported for little penguin colonies in New Zealand and Australia. The differences between colonies are generally attributed to different environmental conditions at the colonies. However, no New Zealand study has compared the foraging behaviour of two neighbouring little penguin colonies that share the same marine environment. The current study compared the foraging behaviour of birds from two colonies in Oamaru, New Zealand, during the guard stage of the 2016 breeding season. These colonies were the Oamaru Blue Penguin Colony (OBPC) and the Oamaru Creek Penguin Refuge colony (Creek). These colonies are less than 1 km apart, so individuals have access to the same marine environment. Data loggers were used to assess at-sea behaviour and to determine the foraging range of little penguins at each colony. All recorded foraging trips during the guard stage were single day trips and which penguins departed from their colony early in the morning and return to their colony in the evening. There were no consistent differences between colonies in foraging and diving behaviours. The mean maximum distance from each colony was < 25 km. There was a difference between colonies in the mean duration of trips, with a longer mean trip duration for Creek colony birds than OBPC birds. The mean return time to the colony was later for Creek individuals. The mean foraging range per trip was greater for Creek individuals than for OBPC birds. This difference in mean values was attributed to a higher proportion of wide-ranging trips by Creek individuals. Practical limitations for the study meant that the sample sizes were smaller than those of some other studies. It is considered likely that if a larger sample size had been possible then the results would have shown no difference between colonies in the mean foraging range per trip during the guard stage in 2016. There were no differences between colonies in diving behaviour variables. The total foraging areas for individuals from each colony were compared between colonies to determine if there were distinct foraging areas for birds from each colony. Distinct foraging areas have been observed for neighbouring populations of conspecifics for many seabird species. However, the foraging areas for little penguins from the OBPC and Creek colony is overlapped and were not distinct. Distinct foraging areas for seabirds from neighbouring colonies is thought to be driven by intra-specific competition, so competition between colonies for foraging areas appears to have been low for Oamaru little penguins during the 2016 guard stage.