The Ecology and Conservation Group
Current Research - Birds

The little blue penguin (LBP), Eudyptula minor, is the world's smallest penguin; found along the southern coastline of Australia and around New Zealand. The North Island subspecies (E.m.iredale) breeds on shorelines extending down from the Northlands as far as the Waikato region in the west, and Gisborne to the east. This includes Little Barrier, Great Barrier, Mercury, and Tiritiri Matangi Islands.

Although listed as a species of 'Least Concern' by the IUCN Red List, LBP are in Gradual Decline in New Zealand. Throughout their range, periodic mass beach wrecks occur and post mortem studies have found poor body condition associated with starvation as the primary cause. At least one wreck event in Australia has been associated with large mortalities of pilchard (Sardinops sagax) and it is speculated that changes in the abundance or distribution of prey species may trigger mass penguin deaths.

Little blue penguin's major prey are small pelagic schooling fish, such as pilchard and anchovy (Engraulis australis), both of which are commercially fished in New Zealand. Little is known about the characteristics of the LBP's foraging range; spatially or temporally. The Department of Conservation is proposing to establish several marine reserves in the Hauraki Gulf, and baseline data is required to assess the success of these no-take reserves, in regards to this species. Recent developments in the miniaturisation and hydrodynamic design of satellite tracking instruments have made it possible to collect this data.

Satellite tracking and time-depth recorders will be placed on at least ten birds per study area and the data analysed in conjunction with estimations of prey abundance from bi-monthly mid-water samples. This study aims to elucidate how patterns of habitat use vary temporally and spatially, across life history stages, and relate these findings to penguin density and breeding success. It will be the first study to describe foraging range and dive profiles for the Northern subspecies of LBP.

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The objective of my research is to document patterns of movement and habitat use of newly translocated New Zealand parakeets and its relationship to origin (i.e. captive vs wild sourced) and proxies of health. Translocations are a widespread tool for conservation worldwide but only recently these have been designed as experiments. Health and immune response of translocated individuals have been widely cited as potential factors affecting success of translocations but these have not been in detail, particularly among parrots.

Specifically, my research aims are the following:

1. Establish three parakeet populations via translocation in the Auckland Region (Motuihe Island, Tawharanui Regional Park and Rakino Island).
2. Explore the relationship between body condition, immune response (assessed using the PHA skin test) and survival of parakeets in a new environment (namely, translocation sites).
3. Determine home ranges of translocated individuals and quantify differences in these between captive-bred and wild-sourced parakeets.
4. Determine habitat use patterns (i.e. vegetation structure and composition) of translocated individuals and quantify differences between captive-bred and wild-sourced individuals.
5. Document the occurrence of selected pathogens in natural and translocated populations of red-crowned kakariki include the remote Raoul Island population.

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New Zealand's isolation and the absence of mammalian predators and in particular the lack of mammals that rely on scent to find their prey have New Zealand enabled to evolve a unique bird fauna, presented by predominantly flightless and nocturnal species. Having adopted features that rather speak for mammals than birds, it is then perhaps plausible that olfaction may be an important aspect of New Zealand's avian ecology, as this historically would not increase their vulnerability to predation and olfaction might play an important role in communication and mate choice.

Furthermore New Zealand is home to one of the most unusual parrots worldwide, the kakapo (Strigops habroptilus), which is known for its strong and sweet smell. The aim of this project is to investigate the role chemical communication may play in parrots and in specific in the kakapo. Understanding the role of the chemical ecology may prove helpful in the conservation of the critical endangered kakapo.

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The little blue penguin is one of the few native bird species which still persists on the New Zealand mainland. However, they are very susceptible to predation by introduced mammals such as mustelids and dogs (Perriman & Steen 2000; Harrigan 1992). The larger colonies are now only found in areas that are not accessible by predators or in areas with some form of predation management (Dann 1994). The Department of Conservation have ranked the blue penguin as low risk or near threatened. According to Taylor (2000), the size of all northern blue penguin populations is unknown; and accurate estimates are needed from as many breeding localities as possible.

Aspects such as population structure, breeding biology, nesting, and foraging behaviour, are important to the well being of a population. There have been many studies into such aspects of the little blue penguin (Kinsky 1960; Dann 1994;Chiaradia & Kerry 1999). However the majority of these studies have been conducted in the South Island of New Zealand or southern Australia, and little is known about the northern populations of little blue penguins. It may seem intuitive that the above behavioural and biological aspects will be affected by predation; however the degree to which predation affects these aspects is unknown.

Comparisons of behavioural and biological aspects of little blue penguin populations will be made between three sites. The first site, Tiritiri Matangi Island, is a protected off-shore island with a few nest boxes available. The second site, Tawharanui Regional Park, is a recently established mainland island with a predator control program. The third site, Ti Point, is a mainland site that is easily accessible by predators.

It is predicted that the sites with a greater level of conservation management and predator control will have a higher breeding success and fledgling rate as a result of reduced nest predation. Body condition and nest fidelity may also be improved by predator control. Individuals with poorer body condition will travel further for food (Weavers 1992) and have a lower breeding success. The sites with less predator control are expected to be the sites from which individuals will make larger foraging trips. More interesting will be the degree of change in these aspects between the different levels of management and how these differences will affect the survival of the population.

This study will also provideimportant baseline information of the little blue penguin population in Tawharanui Regional Park and surrounding area. This will be made available for future research and management decisions.

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I propose to undertake a year-long project on Tiritiri Matangi Island in the Hauraki Gulf (30km east of Auckland) studying ecto- and endoparasitism in little blue penguins (Eudyptula minor). There has been evidence of large parasite loads in little blue penguins and other penguin species, and that this has been detrimental to the birds. It has been found that parasitic load is often associated with starvation. During my thesis year I want to investigate the incidence of ecto-, haemo- and gastro-intestinal parasite infestation in little blue penguins on the island and how this level of infestation correlates with body condition and the health of these birds. This ultimately determines their ability to cope with environmental stresses, contributing to survival and nest success. Therefore I would like to expand the study to include the monitoring of nest success of individuals and relating this to body condition and the presence/absence and extent of parasitism.

I plan to examine the parasitic load of penguins during the breeding and non-breeding seasons (including the moulting period). I propose to develop the study by: comparing parasitic loads from different nest types; examining parasitic loads in chicks; carrying out control experiments on nests; carrying out post-mortems on little blue penguin carcasses collected from the island; and obtaining samples from little blue penguins from other sites for comparison, including samples from captive little blue penguin populations.

Jacqueline Geurts (MSc student) has looked at the breeding and foraging ecology of little blue penguins on the island. We have agreed to collaborate our findings. Our aim is to determine which factors threaten this population, which will enable us to recommend management practices that best suit this species. We propose to publish our results.

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As a result of conservation translocations initiated in 1964, the North Island saddleback has increased from a single island population of < 500 birds to one comprising 12 island populations and an estimated 6000 birds. Most translocations consisted of a single release of 21-40 birds. Some translocated populations have been used for subsequent translocations resulting in populations that have been through up to three successive bottlenecks prior to establishment. Saddleback are poorly flighted and with the exception of one population established through natural dispersal, there is no mixing between islands. The loss of genetic diversity through founder events such as translocations has been well documented but there has been less attention given to the impacts on cultural diversity such as song dialects. Saddleback provide a unique system for examining the impacts of translocation on cultural diversity. The original source population acts as a control while the 11 translocated populations can be treated as experimental units consisting of founder events of known origin, age, size and sex class.

Saddleback by Tim Lovegrove

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The main objective of my proposed research is to study Major Histocompatibility Complex (MHC) alleles associated with malarial parasite Plasmodium and Haemoproteus sp. infections in four New Zealand bellbird Anthornis melanura populations. MHC genes play a fundamental role during immune response and recent studies have linked specific MHC alleles and MHC diversity to malaria resistance and susceptibility. One of my study populations was recently documented to have a malarial blood parasite prevalence of over 50 % and little is known about the other three populations.

Five main research questions comprise the structure of my thesis. First, I will test hypothesis on the temporal and geographic variation in malaria presence/parasitemia in bellbirds and how that correlates with individual body condition. Second, the number of MHC alleles in each population is expected to vary markedly. Also, MHC diversity might be either negatively or positively related to malaria prevalence depending on virulence. Third, neutral microsatellite loci will be used to better understand genetic distances among the bellbird populations and to standardize any MHC variation. The fourth and fifth sets of hypotheses are related to evolutionary theory. A natural experiment involving re-colonization of a mainland population from a retained island population presents the opportunity to study MHC adaptation versus genetic drift. Finally, instances of double infection in single hosts will permit hypotheses that test whether trade-offs in retention of antagonistic MHC alleles result from competitive interactions among malaria parasites.

For three years, blood will be collected from three bellbird populations in the Hauraki Gulf region, North Island at regular intervals (Tiritiri Matangi Island, Tawharanui Regional Park, and Little Barrier Island) and once from a fourth population, Kaikoura, South Island, New Zealand.

This research will be conducted in conjunction with ongoing research on malarial infections in New Zealand avifauna by Dr. Dianne Brunton and Dr. Rosemary Barraclough at Massey University, Auckland. The genetics work will be conducted in collaboration with Dr. Allan Baker at the University of Toronto. The results of this PhD thesis will help further the understanding of disease susceptibility in wild endemic bird populations and of the complex evolutionary dynamics involving immunity to disease.

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The North Island brown kiwi are in serious decline due to human induced habitat destruction and predation from introduced mammals (Hitchmough et al. 2007). Thus, most kiwi populations are suffering significant recruitment failure of young birds into the breeding population and occur at low densities (Hitchmough et al. 2007).

Previous studies suggest that North Island brown kiwi form long term pair bonds and exhibit monogamy (Taborsky & Taborsky 1999). However, there is little known about kiwi social behaviour despite its conservation importance and iconic status within New Zealand. Moreover, the North Island brown kiwi possess some unique characteristics of reproductive biology and parental care which lead to the intriguing possibility that this species could be polyandrous. Density and thus the availability of potential mates may have an effect on kiwi mating behaviour and social organisaton. The study population of this research is one of the few remaining high-density kiwi populations and may represent kiwi density prior to human arrival in New Zealand. By studying this population we may learn how kiwi behaved socially in pre-human New Zealand and how flexible their mating system may be in different ecological conditions. This research will investigate the social organisation and the social mating system on the basis of collected field data obtained from radio-tagged kiwi. Our preliminary results suggest that kiwi mating behaviour may be density depenedent; low-density populations exhibit monogamy while high density populations exhibit polyandry. These findings will be corroborated by determining the underlying genetic mating system using DNA analyses.

Due to the pressures of predation and habitat loss, the translocation of small numbers of kiwi to predator free offshore islands has become an important tool in kiwi conservation (Colbourne 2005). However, the conservation benefits for the species' is only short termed while long term consequences such as inbreeding or low genetic variation are neglected (Jamieson et al. 2006). The kiwi population which is the focus of this research has originated from a small founder popualtion introduced to an offshore island some four decades ago. Thus we aim to investigate the level of genetic variation within this population to help us understand the effects of the bottleneck the population has gone through. Up to date no study has been carried out to investigate the effects of population bottlenecks on the genetic variation of a closed, introduced kiwi population. Effective kiwi management requires an understanding of their life history characteristics and of genetic relationships between individuals in a population in order to prevent the species from losing viability or going extinct due to the loss of genetic variation.

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Grey warbler by Michael Anderson

The grey warbler (Gerygone igata) is a widespread and abundant native passerine. It is one of the few native passerines to have been successful following human induced habitat modification. This makes them an interesting study species for investigating the geographical variation of their song. Previous studies that have investigated the vocal dialects of native passerines (e.g. saddleback, Philesturnus carunculatus; and bellbird, Anthornis melanura) have done so on species that are geographically isolated. This research will investigate the development and maintenance of song dialects in a species that does not consist of geographically isolated populations. This allows the development of dialects through other means, rather than existing primarily due to geographic isolation.

Shining cuckoo by Michael Anderson

In recent years, there have been considerable advances in the understanding the selective pressures imposed by brood parasites and their hosts on each other, but there remain many questions about the degree to which coevolutionary arms races escalate between host and parasite. The grey warbler is the only species in New Zealand that is a host of the brood parasite, the shining cuckoo (Chrysococcyx lucidus). However, there has only been a limited amount of research into this host/parasite system, which has been restricted to the South Island. Research will be conducted to establish some of the fundamental aspects of this system, such as the rate of brood parasitism, timing of parasitism and the development of cuckoo nestlings. The coevolution of these two species will also be investigated, including the parasite mimicry of host nestlings through acoustic and visual cues, and the discrimination ability of grey warblers to parasite nestlings. Further research will include the host selection process used by the shining cuckoo, which may offer further insights to its exclusive parasitism of the grey warbler, and also the development of conspecific recognition abilities of the shining cuckoo.

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