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Studies of the life history of school sharks (Galeorhinus galeus) : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Ecology at Massey University, Albany, New Zealand
(Massey University, 2025-09-26) Burton, Alex J. C.
The school shark (Galeorhinus galeus) is a globally distributed, migratory species that was recently reclassified, globally, as Critically Endangered due to all but the New Zealand population having collapsed due to overfishing. Effective management and recovery of these populations is currently limited by a lack of accurate biological information, which is increasingly difficult to obtain due to the scarcity of school sharks throughout their range. By studying the last stable school shark population, located in New Zealand, the aim of this thesis is to provide accurate information on the biology of school sharks to better inform their management worldwide. Specifically, this thesis examines allometric relationships, inter-population variation in life-history stage transitions, intra-population variation in juvenile growth rates, extent of the transfer of elements from mother to pups, and the spatio-temporal connectivity of habitats important to life-history. To enable better standardisation of length data when combining datasets, the optimal model for converting between different length measurements of school sharks was first identified. After standardising length and life-history stage data, a novel Bayesian generative classifier model suggested that length at life-history stage transitions varied among several, globally distributed, school shark populations. A study of juvenile school shark growth across several regions in New Zealand (i.e., Kaipara Harbour, Tasman and Golden Bays, and the Canterbury Bight) revealed that somatic (increase in body length with age) and hepatosomatic (increase of energy stores in the liver with age) growth was consistent among regions, but body condition was generally greater in the Canterbury Bight compared to other two regions. Tracking the year-long, three-dimensional movements of large female school sharks tagged in the Kaipara Harbour with satellite tags showed these sharks dispersed to several potentially important reproductive and feeding habitats around New Zealand. Finally, nutrients and essential and non-essential elements maternally provided to developing young were likely sourced from those assimilated from the mother’s diet during vitellogenesis. This thesis has national and international implications for school sharks and other elasmobranch species, as it provides information and techniques crucial to better understanding the biology of species that is needed to inform more effective management and recovery efforts.
Development of a theoretical approach for investigating the occurrence of boredom in animals : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Manawatū, New Zealand
(Massey University, 2024-12-27) Heslop, Morgan Victoria
Many domestic and captive wild animals across the globe are kept under highly constrained conditions, and there has been a growing concern that boredom might represent a major source of welfare compromise for these animals. To understand how significant an impact animal boredom represents, there is first a need to improve understanding of what boredom is and how it can be recognised. The aim of this thesis is to systematically examine the concept of boredom and how it can be recognised in animals kept under human management. This investigation begins by reviewing current knowledge of boredom in humans, culminating in the presentation of a framework that demonstrates the relationships between the environmental antecedents, cognitive and physiological correlates, social and cultural features and behavioural outcomes of self-reported boredom. In humans, boredom is a temporally fluid emotion that is thought to function as a goal-switching signal, occurring when there is a mismatch between the availability of cognitive resources and environmental demands on those resources. The specific cognitive and behavioural changes associated with boredom are expected to change over time, but the pattern of these changes is not yet well characterised in humans, making it challenging to determine when to look for expected responses in animals. The framework is then used to identify which aspects of boredom are measurable and manipulable to systematically investigate boredom in animals. While various correlates are theoretically measurable, the most promising measures of boredom are behavioural; three behavioural strategies are expected to occur in response to boredom, characterised as goal-switching, goal-perseverance, and non-goal-related behaviour. Manipulations to increase the likelihood of boredom-related behavioural outcomes involve altering either the availability of the subject’s cognitive resources or the environmental demand, to produce a mismatch. A novel model is introduced to describe the predicted relationships between the expected behavioural pattern and the availability of cognitive resources relative to environmental demand, as well as perceived meaning of the current activity or task and the animal’s judgement of control during boredom. The model predicts that when there is a resource-demand mismatch, or when an activity/task is low in meaning, boredom will prompt behaviours that aim to either change goals or regulate cognitive resources and demand to support persevering towards the current goal. In situations where the subject does not judge adequate control to successfully alleviate boredom through these strategies, the model predicts the occurrence of non-goal-related behaviours. The model is used to investigate how existing research on environmental conditions and ‘enrichment’ (mainly through increased complexity) contributes to our understanding of boredom in animals. One important knowledge gap is understanding how a lack of change over time (i.e. monotony) is perceived as an antecedent to boredom in animals. The way monotony, so defined, may occur in the lives of animals is further explored. Although monotony is recognised as an antecedent of boredom in humans, it may not lead to boredom in all animals. The evolutionary background of a species is predicted to influence whether monotony is aversive to members of that species, and different types of monotony may be aversive to, or preferred by, different animals. Consideration of the key features of monotony led to the development of an experimental paradigm for investigating the behavioural outcomes of task-related monotony in rats, with a view to observing whether the predicted strategies associated with boredom occur during monotony in a species that is expected to find such conditions aversive. The planned experiment could only be completed with a single animal, and the data recorded could not be fully analysed within the timeframe of this PhD. Nonetheless, the paradigm provides a potential method for investigating how monotony is perceived by animals and identifying any associated welfare impacts. To date, there is a small amount of focussed evidence that animals in restrictive environments exhibit attempts to switch goals when opportunities are made available. However, most studies only report collapsed data such as the overall duration of different behaviours, precluding the recognition of behavioural patterns that indicate the occurrence of boredom according to the model developed here. Understanding these behaviours requires continuous monitoring to observe wider behavioural patterns over time. The model presented supports the systematic investigation of boredom in animals by generating predictions about the expected behavioural outcomes in situations with different features, which can be further examined and tested in future research. The exploration of boredom presented here contributes to a growing area of animal welfare science. The recognition and alleviation of boredom are both important and it is hoped that this work will contribute to a strong foundation that will support and provide rigour to future studies.
Analysis of current methods and Welfare concerns in the transport of 118 horses by commercial air cargo companies
(BioMed Central Ltd, 2024-04-26) Felici M; Cogger N; Nanni Costa L; Riley CB; Padalino B
BACKGROUND: Studies on equine air transport practices and consequences are scarce. This prospective study aimed to describe horse and air journey details and practices, document how horse behavior and health changed during the air transport phases, quantify the occurrence of welfare issues, and identify possible associations between horse and journey details, air transport practices, and welfare issues. RESULTS: Data were collected from before departure to five days after arrival on 118/597 horses traveling on 32 commercial air journeys on different routes, varying in duration and conditions. Most horses were middle-aged warmblood females, 26% of which were pregnant, and being moved by air for sales. Before flying, most were quarantined (median: 18; IQR: 9-53 days), and their fitness for travel was certified by veterinarians. At the departure airports, external temperatures varied from - 6 °C to 33 °C, and horses were loaded by experienced flight grooms (median: 35; IQR: 15-40 years) into jet stalls (three-horse: 87%, two-horse: 13%). During the flights, horses were regularly watered (water intake median: 14 L) and fed ad libitum (feed consumption median: 8 kg). At the arrival airport, horses were unloaded from the jet stalls, and external temperatures ranged from - 5 °C to 32 °C. Then, all horses were transported to arrival quarantine by road. Air transport phases affected horses' health status and behavior; increased heart and respiratory rates and behaviors, such as pawing, head tossing, and vocalization, were mainly identified at departure and arrival. Horse interaction, nasal discharge, increased capillary refill time (CRT), and abnormal demeanor were observed more often one hour before landing while resting and normal capillary refill time were more often displayed five days after arrival (all P < 0.01). One hour before landing, horses with bad temperament and horses of unknown temperament were more likely to develop nasal discharge when transported in winter and autumn (P < 0.001). The likelihood of an increased CRT was associated with shorter flights in horses of unknown travel experience (P < 0.001). Ten horses were injured, and 11 developed pleuropneumonias (i.e., shipping fever). CONCLUSIONS: Air transport is a complex procedure with several different phases affecting horse health and behavior. Therefore, experienced staff should carefully manage each horse before, during, and after air journeys to minimize welfare hazards.
Modulation of enteric neural activity and its influence on brain function and behaviour : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutritional Science at Massey University, Manawatu, New Zealand
(Massey University, 2024) Parkar, Nabil Jamil
The gut-brain axis (GBA) facilitates bidirectional communication between the enteric nervous system (ENS) of the gastrointestinal (GI) tract and the central nervous system (CNS). The location of the ENS along the GI tract enables it to serve as a relay station along the GBA. A key regulator of the GBA is the diverse population of microbial communities inhabiting the GI tract, known as the gut microbiota. Due to its proximity to the ENS, gut microbes significantly influence ENS functions, such as gut motility, and also impact brain function and behavior. A diverse and healthy gut microbiota is crucial for normal GI physiology and mental health. Understanding the physiological host factors that influence and control the gut microbiota is essential for grasping its variability in health and states of dysbiosis. Movement of luminal content along the GI tract, primarily driven by rhythmic contractions of GI smooth muscles, affects gut microbiota growth and population dynamics. This research involved a series of ex vivo and behavioral experiments in rodents to better understand ENS control of gut motility and its impact on anxiety-related behavior. Initially, the effect of a specific pharmacological agent on colonic motility patterns was evaluated using ex vivo techniques. Observations from this study provided fundamental insights into ENS function and its regulation of colonic motility, laying the foundation for further research on how altered colonic motility via ENS manipulation affects gut microbiota composition and anxiety-related behavior. The second study investigated whether pharmacological modulation of the ENS, resulting in reduced colonic motility, affected the gut microbiota. Results revealed significant changes in gut microbiota composition, including decreased abundance of certain bacterial species and alterations in community structure. The final study aimed to understand the relationship between ENS manipulation, brain function, and behavior by inducing changes in gut motility. Anxiety-related behavior was assessed in rats using open field and elevated plus maze tests, focusing on those exposed to a pharmacological agent that slowed colonic motility via specific ENS receptors. To determine if behavior changes involved specific neural pathways, brain gene expression in key regions was studied. Additionally, the potential relationship between gut microbiota and brain function was explored, assessing if ENS modulation and behavioral effects correlated with changes in gene expression and microbiota profiles in the large intestine. Findings indicated that ENS modulation altered anxiety-related behavior in a sex-specific manner, with female rats showing increased anxiety and corresponding changes in brain and proximal colon gene expression compared to males. This study highlighted sexually dimorphic gut-brain communication and suggested multiple genes/pathways may influence anxiety-related behavior in females. This comprehensive exploration through three interrelated studies has provided new insights into the regional specificity of ENS receptors in regulating colonic motility, the impact of slowed gut transit on microbiota composition, and the physiological consequences of ENS modulation on brain function and anxiety, with associated sex differences. A combined analysis of these findings discusses their implications for understanding the ENS as a key player in regulating the gut-brain axis.
Understanding the variations in grazing and rumination behaviours and their associations with production parameters in individual grazing dairy cows : a thesis presented in partial fulfilment of the requirements of the degree of Doctor of Philosophy in Animal Science at Massey University (Manawatū) New Zealand
(Massey University, 2023) Iqbal, Muhammad Wasim
This thesis aimed to understand: 1) the accuracy of an accelerometer-based sensor to monitor grazing and rumination behaviours in dairy cows; 2) grazing and rumination behaviour patterns and time budgets over 24 hours; 3) potential factors to influence grazing and rumination behaviours; and 4) effects of grazing and rumination behaviours on production parameters. To do this, data including, but not limited to, grazing time, rumination time, measures of cow performance (e.g., milk production and composition, body weight and body condition score), days in milk, and breeding worth index of 162 grazing dairy cows were collected for three consecutive lactation seasons (2018-2021). The analysis was performed on individual study years and results were reported separately for each year. First, the accuracy of AﬁCollar, an accelerometer sensor-based automated device to monitor and record grazing and rumination behaviours in dairy cows was evaluated for a grazing-based system. Spring-calved lactating cows (n = 48) wearing AﬁCollar were continuously visually observed for 8 hours (9 am to 5 pm) to quantify minutes per hour spent grazing and rumination. The behaviours being observed were also recorded with the AﬁCollar and compared with visual observations using Pearson’s correlation coefﬁcient (r), concordance correlation coefﬁcient (CCC), and linear regression. A strong association was found between the data collected by AfiCollar and the data obtained through visual observation for grazing time (r = 0.91, CCC = 0.71) and rumination time (r = 0.89, CCC = 0.80) with a signiﬁcant linear relationship between both datasets (p<0.05). Furthermore, variations in the temporal patterns (min/h) and time budgets (% min/day) of grazing and ruminating behaviours recorded using AfiCollar were evaluated in spring calving lactating (n = 162) Holstein-Friesian (HFR), Jersey (JE), and Holstein-Friesian Jersey crossbreed (KiwiCross, KC) cows in their different lactations (1st, 2nd, 3rd, 4th), and with different breeding worth index values (103151). A repeated measure design was performed in SAS using PROC MIXED considering the fixed effects of breed and lactation, the random effect of individual cows, and hours of the day as repeated measure to evaluate their effects on hourly patterns and time budgets of grazing, rumination, and idling behaviours. Regardless of the seasonal variations and feed consumed, cows spent most of their daytime grazing (with peaks around dawn and dusk) and most of their nighttime ruminating. Grazing and ruminating patterns were similar between cows from different breeds and lactations, however, JE cows grazed slightly longer than HFR and KC cows; and first-lactation cows grazed slightly longer than mature cows in their later lactations. The onset and cessation of grazing activity by the cows were adjusted according to varying day lengths by season. In addition, a general linear (PROC GLM) mixed model was fitted to test the effects of days in milk, breeding worth, breed, lactation year, individual cow, season, feed, and their interactions on variations in grazing time, rumination time and their relationship. Results indicated that grazing time varied among breeds in Year-2 and Year-3 and among lactation years in Year-1. Rumination time differed between breeds in only Year-3, and it remained the same within lactation years. Grazing time and rumination time varied among different seasons that were related to varying supplementary feeds. Days in milk, breeding worth (except Year-3), and the individual cow had effects (P<0.05) on grazing and rumination times. Grazing time and rumination time had a negative relationship with each other that varied between different seasons but remained the same among different breeds and lactation years. The variance in grazing and rumination times was mostly explained by individual cows (up to 24%), season (up to 12%), and feed (up to 8%). Moreover, results also showed that grazing and rumination times had positive associations with milk yield, fat, protein, and solids. Grazing time had negative and rumination time had positive associations with liveweight, while both grazing time and rumination time had negative associations with body condition score. Grazing time explained up to 1%, and rumination time explained up to 7% of the variance in milk yield, milk fat, protein, and solids. AfiCollar can reliably monitor grazing and rumination behaviours in dairy cows, however, its accuracy can be improved for a grazing-based system. The animal itself, the season, and the feed are the potential sources of variation in grazing and rumination behaviours and should be considered for management decisions to address the animal’s behavioural requirements. Grazing and rumination behaviours are moderately correlated with performance parameters and explain a small proportion of variance in animal productivity.
Biological control ecology of Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) on Bactericera cockerelli (Šulc) (Hemiptera: Triozidae) : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Science (Entomology) at Massey University, Manawatū, New Zealand
(Massey University, 2023) Chen, Chen
Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) is an important primary parasitoid of tomato-potato psyllid Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), a serious invasive pest of solanaceous crops. It kills its hosts by both feeding and parasitisation. However, its biological control ecology is still not well known, making it difficult to develop an effective biological control programme using this parasitoid. In this thesis, I investigated adult circadian rhythms, diets, life history strategies, and host selection behaviour in T. triozae. My results show that most emergence occurred in the morning and most mating took place early the next morning. Oviposition only occurred during the daytime, peaking between mid-morning and mid-afternoon while host feeding had three peaks in the early morning, late afternoon, and dawn. Adults fed with honey for four days with no access to hosts or with water or yeast for one day followed by host feeding for three days had similar longevity and lifetime pest killing ability. Adults fed with only water for one day immediately before release had significantly greater intrinsic rate of increase, shorter doubling time, and higher daily fecundity peak. Adults fed with honey or yeast for one day followed by host feeding for three days significantly flattened their daily oviposition curves. T. triozae females could feed on nymphs of all instars but preferred mid-aged ones for feeding. Most parasitisation occurred on older nymphs. Host feeding and parasitism peaked during the first week of female life and declined markedly after two weeks. Parasitoids allocated more fertilised eggs to older and larger nymphs. The oviposition of fertilised eggs peaked when females were four to five days old, with > 90 % of daughters produced during the first half of their life. There was a positive relationship between the host size at parasitisation and parasitoid offspring fitness. The parasitoid behaviours consisted of encounter, evaluation, piercing for feeding, feeding, oviposition probing, and oviposition, and host defence behaviours included body swaying and escaping. Female wasps were more likely to encounter and evaluate older and larger hosts. However, encounter and evaluation did not necessarily translate into feeding and oviposition success. Older nymphs had more resources, thicker integument and stronger defence ability and the opposite was the case for younger ones. The present study provides novel knowledge for development of effective T. triozae mass rearing, shipment, and release programmes for the control of B. cockerelli.
Social interactions in New Zealand common bottlenose dolphins (Tursiops truncatus) : association dynamics, skin diseases and aggressive injuries, and variations in vocal signals : a thesis presented in partial fulfilment of the requirement for the degree of Doctor of Philosophy in Conservation Biology at Massey University, Auckland Campus, New Zealand
(Massey University, 2022) Patin̋o-Pérez, Jessica
Social behaviour is described as a series of interactions between two or more members of the same or different species that usually benefits all the individuals involved. Individuals form strong bonds because of these interactions, which might be cooperative, hostile, mutualistic, or altruistic. Depending on the nature of the relationships and participants, social behaviour can lead to the establishment of distinct social systems. Although it is evident that social behaviour does not have to be selfless, the question of why and how social behaviours occur in animals is still being debated. According to Krause and Ruxton (2002), sociality emerges when the advantages of long-term social contacts outweigh the drawbacks of such close relationships with conspecifics. Among the advantages of living in a group are increased opportunity for food and mating, as well as protection from predators. This sociality, on the other hand, might have negative implications, such as increased rivalry for mates and resources or increased disease transmission risks. I investigated multiple aspects of the social lives of common bottlenose dolphins Tursiops truncatus (hereafter bottlenose dolphins) in New Zealand. Historically, the north-eastern North Island bottlenose dolphin population has been intensively studied at the Bay of Islands since it was the only place where dolphins are constantly sighted. A rapid decline in this population and high calf mortality raised concern about the viability of this population. The key objective of my research was to understand how different social aspects influence the population of bottlenose dolphins at Great Barrier Island (GBI), New Zealand, an area that was recently describe as a ‘social hub’ for the species. Although, throughout my thesis I talk about the population of dolphins present in GBI, it is important to keep in mind that this is one part of the entire North Island population. In the first part of my thesis, I describe the social structure of bottlenose dolphins in GBI using historical data from the Bay of Islands (BOI) and GBI, in addition to my own data. I analysed their social structure by examining: (1) preferred/avoided companions, (2) strength and distribution of associations, (3) temporal and spatial patterning of associations, and (4) residence times. The analysis of BOI-GBI showed two distinct social communities, each of which is made up primarily of members photographed only in their respective areas. Only a few individuals were identified in both areas. For GBI, two datasets were analysed: 2011-2013 and 20015-2019. During both time periods, the population exhibited low levels of association, characteristic of fission-fusion societies like bottlenose dolphins, but the populations also showed some structure, with dolphins forming long-lasting bonds with some individual and avoiding others. Moreover, during 2015-2019, two social communities were identified in the population, exhibiting different ranging patterns and pattern of association within communities. The temporal analysis showed that during 2011-2013, the population exhibited a combination of stable associations among individuals and other individuals that associate, disassociate, and may reassociate again over extended periods of time. During 2015-2019, dolphins associate for short periods of times before breaking up, happening at two different times. Analysis of residency times during 2011-2013, showed that the models including emigration + reimmigration were the best to describe the population, while during 2015-2019, were the models including emigration/mortality. Bottlenose dolphins associate in groups that frequently change in size and composition, characteristic of fission-fusion societies. Skin lesions and tooth rakes can be used to assess natural and anthropogenic pressures within a population, which is useful information for better understanding population dynamics. In addition, tooth rake marks are a measure of the level of social contacts within a population and are usually the outcome of inter- and intra-specific interactions. Gregariousness is a major component in disease transmission and increases the likelihood of aggressive confrontations. When it comes to diseases, animals with a high incidence of interactions with others will increase the chances to spread diseases, putting their populations at risk. In this thesis, I described for the first time the prevalence of skin lesions and tooth rakes for the north-eastern population of bottlenose dolphins. In addition, I described the skin lesions found in, and determined the location of, the skin lesions and tooth rakes on dolphins’ bodies. I also proposed a protocol to assess skin lesions and what are the implications for future studies. Finally, I tested if there was an association between skin lesions and tooth rakes, and the strength of the dolphins in their social network. I wanted to know if presence or absence of tooth rakes was defined by the strength in their social network and if dolphins with a higher coverage score of tooth rakes will have a higher strength in their social network. In addition, I examined if tooth rake scores were different based on the presence and absence of skin lesions. From the literature, I found 19 skin lesions with distinct and non-overlapping definitions. These lesions were the foundation of the protocol that I used to assess lesion presence in my population. Eight skin lesions were present in bottlenose dolphins at Great Barrier Island, with different prevalence in the population and varying distribution across different parts of the dolphin body. Pale lesions had the highest prevalence at 84.4% and were found across four body parts, but mainly in the dorsal fin. Similarly, black lesions, white-fringe spots, nodules, and dark-fringe spot were found in four body parts but their prevalence in the population were lower (33.1%, 17.5%, 11.7%, and 15.6%, respectively). Finally, spotted lesions (10.4%), white fin fringe (5.84%), and tattoo-like disease (4.54%) had the lowest prevalence and were found in three, two, and one body region(s), respectively. Tooth rakes also had a high prevalence in the population (94%), and they were found mostly on the dorsal fin (100%, n = 150), followed by mid-flank (90.2%, n = 139), and anterior section (88.3%, n = 136). The mean coverage score did not change significantly over time (images were compared up to 20 months apart). From the 150 dolphins included in the tooth rake analysis, individuals sighted four or more times were included in the analysis of tooth rakes and strength of associations, giving a sample size of 50 dolphins. I found that the strength of the individual (i.e., it is the individual’s gregariousness) in the social network does not affect the tooth rakes an individual has and having tooth rakes is not dependent on strength. In addition, coverage score (a value obtained dividing the presence of skin lesions in 12 body parts by their visibility) did not change with the presence of skin lesions. In this chapter, I emphasised the need to determine the overall health of cetaceans in the North Island, as well as the need for more precise and systematic evaluations of the skin lesions of this population and other cetaceans in the region. Cetaceans are highly vocals animal that depend on sound to communicate, navigate, and find food. Most dolphins can produce three different types of sound, from which whistles have been the most studied due to this type of vocalisation being within the human hearing range and more easily visualised in spectrograms for analysis. Whistles are narrowband, frequency modulated sounds with strong harmonic structure and are used in social interactions. Geographic variation in whistle characteristics has been reported in many populations of bottlenose dolphins around the world and the causes of this variation are diverse. For the first time in New Zealand, I have compared the variation in whistle characteristics of two isolated populations of bottlenose dolphins, GBI and Fiordland, using seven time-frequency variables. In addition, I compared the parameters between these isolated populations using Random Forests analysis (RF) and assessed the influence of location, group size, and presence of immatures on these characteristics. Finally, I compared the whistle characteristics of bottlenose dolphin populations from around the world with New Zealand populations using a hierarchical cluster analysis. Whistle characteristics of both populations were similar to other populations around the world, surprisingly, my populations were similar to other populations from the northern rather than the southern hemisphere regions. A comparison of whistle parameters between GBI and Fiordland, showed that the Fiordland population had longer whistles and more inflection points than whistles from the GBI population. Whistles from these two populations were distinct enough to be correctly allocated to one population based on acoustic measures alone with a 90% of accuracy. The most important variables for classification were whistle type contour, duration, and end frequency. I obtained two principal components from the NIPALS PCA. The first principal component (PC1) explained 55.6% and the second component (PC2) explained 44.4% of the variance. Linear Mixed Models on PC1 and PC2 were used to assess whether whistles acoustic parameters were influenced by location, group size, and presence of immatures. I found that PC1 was not different between areas or with the presence of immatures. However, minimum frequency and duration differed between the two populations (location). Overall, my research has produced significant new knowledge on the social structure, prevalence of skin lesions and tooth rakes, and geographic variation in vocalisations of bottlenose dolphins. My research provides better understanding of the high degree of social and acoustic plasticity of bottlenose dolphins by applying state-of-the-art approaches such as social network and random forests analyses to multiple temporally and spatially diverse datasets. In addition, I developed a useful tool for non-invasive categorisation of infectious skin diseases that can be used by researchers and conservation practitioners worldwide to assess the health of individuals and populations.
Assessment of positive emotion in horses : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Manawatū, New Zealand
(Massey University, 2022) Stratton, Rachael Bridget
Objective, non-invasive indicators of the subjective experience of positive emotion are required to support assessment and improvement of animal welfare. Emotion is unique to the individual and indicators of emotion are indirect. The aim of this thesis was to ascertain if body and facial behaviours and physiological parameters reflected the emotional experiences of horses. Following review of the theoretical and experimental literature, three experiments were conducted, and an alternative emotional arousal-valence framework was proposed. Based on the preferences of individual horses, the relative arousal level and emotional valence induced by four stimuli (wither grooming, motionless person, intermittent spray, and being left alone) were ordered. Behavioural and physiological parameters were then measured during exposure to each stimuli. The indicators of contrasting affective experiences in horses were found to be heart rate, heart rate variability, eye temperature, and behaviours involving legs, neck, tail, ears, eyes, eyebrows, mouth, chin, and nares. Several behaviours differed across all three arousal levels or valence levels. Positive emotional valence was indicated by a decreased rate of neck very low, left ear forward, left or right ear back, blink, angled eyebrow, nares flared, nares neutral, and/or an increased rate of chin wobble, small eye aperture, or oral investigation behaviours. Higher arousal was indicated by an increased rate of neck very high, tail swishing, or higher odds of contracted lips, and/or a decreased rate of right ear forward or to the side behaviours. Reduction from 16 to six parameters may be possible. The findings may be used to aid interpretation of horse emotional experience and in the assessment and improvement of horse welfare. The research approach and framework described in this research may be suitable for future research in horses and other species.
The role of personality and behavioural plasticity in common blackbird (Turdus merula) reproductive success : a thesis presented in partial fulfilment of the requirement for the degree of Doctor of Philosophy in Ecology at Massey University, Auckland Campus, New Zealand
(Massey University, 2022) Tavasoli, Mehrnaz
Behavioural biologists have focused on differences between species and populations in the past, while the importance of individuality in behavioural traits has been neglected for a long time. Within a population, behavioural phenotypic variation between individuals is common (Laland and Hoppitt, 2003). Recently the study of behavioural traits in individuals has attracted noticeable attention. This has resulted in behavioural ecology researchers developing a strong interest in the concept of animal personality, plasticity, and the role of individual variation in shaping behavioural traits. Additionally, behavioural ecologists have found different correlations between behavioural traits in terms of “behavioural syndromes” (Garamszegi and Herczeg, 2012). Behavioural phenotypes may cause different lifestyles, influencing life-history strategies in populations (Cote et al., 2008; Edenbrow and Croft, 2011). I investigated in depth the breeding biology and behavioural traits of a population of common blackbirds (Turdus merula; hereafter blackbirds) in New Zealand during breeding and non-breeding seasons from 2017 to 2019. In addition, I studied behavioural variation in this species. The key objective was to focus on how personality and plasticity in traits contribute to reproductive success in this species. My study used field observations and experimental approaches to investigate blackbird behavioural variation and its consequences for reproductive success. I presented breeding biology of blackbirds by investigating three key objectives: breeding biology and chronology, nest characteristics and parental provisioning in blackbirds. I found that blackbirds had a consistent number of eggs per clutch (mean= 2.9 eggs). I found a strong positive correlation between clutch size and latitude from blackbird breeding data around the world. Within breeding pairs that had more than one clutch, the number of fledged nestlings was significantly greater in the last clutches. Nests close to the road had a higher chance to be successful and fledged chicks. These results indicated evidence that predators strongly influenced the breeding success of blackbirds across the season. In addition, I found that the nest diameter increased across the breeding phases (from built to fledged chicks). In contrast, the nest thickness, internal nest depth, and external nest depth decreased. There was a positive correlation between the nest thickness/external nest depth and the number of eggs per clutch. Male and female blackbirds shared chick feeding equally. Additionally, I investigated the variation of behavioural traits of blackbirds using two approaches: observational and experimental. In the observational approach, I recorded activity, vigilance, aggressiveness and shyness behavioural traits. The experimental tests aimed to measure risk-taking within individuals, neophobia, and antipredator behaviour within paired blackbirds. Here, I focused on four objectives: 1) determine explanatory factors that influence behavioural traits (e.g., weather conditions, sexes and age, human modification), 2) estimate repeatability and consistency of all behavioural traits over different time scales within individuals, 3) examine the correlation between behavioural traits, 4) evaluate the relationship between behavioural traits and reproductive success within individuals. My results showed that activity, aggressiveness, and risk-taking behaviours increased significantly in the breeding season within individuals. Minimum temperature significantly affected the variation of behavioural traits. In addition, in the presence of a novel object, movement around the novel object and inspection time significantly increased in paired blackbirds. Inspection declined by increasing the number of trials. My results also demonstrated that the blackbird’s movement around the novel object was influenced by age and the number of chicks. Pairs that had more chicks had a greater number of movements around the novel object. Nest visits by paired blackbirds declined in the presence of the novel object and a greater number of people. Furthermore, in the presence of a predator model, blackbirds showed aggressive (attack-alarm) and non-aggressive responses (they did not alarm and attacks and fed chicks) toward the predator model, with highly aggressive and less aggressive pairs. The aggressive responses of blackbirds were affected by the age and number of nestlings in the nest. Repeatability analysis showed that the onset of egg-laying and the nest's thickness were moderately repeatable within females. Selected behavioural traits in the context of foraging were not repeatable (movement , aggressiveness, vigilant, shyness were highly flexible). However, I found that risk-taking behaviour was moderately repeatable within juvenile females and males (during breeding season) and tended to decrease in the non-breeding season. Neophobic response variables were moderately repeatable within paired blackbirds. Within pairs, antipredator responses were highly repeatable. In contrast, parental nest visits had a low repeatability estimation. Furthermore, the behavioural syndrome analysis revealed a positive correlation between activity and shyness. I also discovered risk-taker blackbirds were more vigilant. Regarding the consequences of behavioural traits on blackbird breeding, I found that shyer blackbirds had a greater number of fledged nestlings per season. In addition, blackbirds who were risk-takers (shorter FIDs, flight initiation distance) produced more eggs per season. Antipredator responses and neophobia in blackbirds were also influenced by breeding investments of blackbirds. Movement round the novel object (neophobic response) and aggressive response toward a predator increased in pairs with a greater number of chicks. In the post-stress situation (predator presentation), pairs with more chicks in their nests returned to their nests sooner (shorter latency) and had a greater number of post-stress nest visits. Additionally, I investigated the response of male blackbirds to different conspecific songs by two playback experiments. In the first experiment, I investigated if blackbirds display different responses to playback songs from males of varying levels of aggressiveness. I also investigated the effect of anthropogenic disturbance, parental care and breeding success on the response of blackbirds to the playback. In the second playback experiment, I examined whether male blackbirds discriminated songs (a long-range signal) from neighbouring and stranger conspecifics. Results from my playback experiment revealed that there were no differences in the response of male blackbirds to the songs from aggressive and non-aggressive blackbirds. Interestingly, blackbirds that had their territories close to the road showed stronger responses toward the playback songs. In addition, there was a positive correlation between the response of male blackbirds and the number of nest visits during the chicks rearing. My results from the second playback experiment showed that a male blackbird responded equally to the dawn songs from his neighbours and strangers, while his response to the songs from far strangers (blackbird’s songs recorded in Europe) was weaker than New Zealand blackbird songs. However, I also found that males respond to stranger blackbirds' daytime songs stronger than those from the neighbour, which confirmed the “Dear Enemy” theory in blackbirds. My research is significant in that it is one of the first studies of breeding and behavioural traits of blackbirds in an urban population of New Zealand. It provides important highlights about intra-individual variation in behavioural traits, and its fitness consequences on the breeding success of blackbirds.
Population dynamics and behavioural ecology of two isolated populations of the Floreana mockingbird : laying the basis for its reintroduction : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Conservation Biology at Massey University, Auckland, New Zealand
(Massey University, 2021) Rodriquez Reyes, Enzo Marcelo
Translocations are one of the most important conservation actions in the recovery of endangered species, these imply the movement of live individuals from one area to another. To ensure the success of translocations, different logistics and species-specific ecological factors need to be considered. Since the early 2000’s, there have been calls to reintroduce the endangered cooperative breeding Floreana mockingbird, to Floreana Island (Galápagos Archipelago) where they became locally extinct due to habitat loss and invasive species. The species currently inhabiting two small islets off the coast of Floreana with no recent history of connection between populations. However, our understanding of reintroduction strategies for the mockingbird is based on monogamous breeding species, not on cooperative breeding species. In this thesis, I explored demographic and behavioural aspects of the species that might facilitate the reintroduction to Floreana. Firstly, I described a non-invasive method that will help will the correct sexing identification and monitoring of Floreana mockingbirds. Furthermore, I assessed the probability of survival of the species using capture-mark-recapture (CMR) models and the influence of precipitation on the survival rate, recruitment of individuals, and population growth. Overall, the population seem to be stable with a slight decrease in one of the populations. Additionally, I explored ecological factors such as vocalization and sociality. I investigated the hypothesis of possible differences in vocalisations between individuals from the two remnant populations. I found an acoustic divergence between populations that could be explained by the influence of cultural drift and morphological differentiation as an effect of isolation, lack of gene flow, and cultural exchange. Finally, I investigated the social structure of the Floreana mockingbird and the probability of group disruption during translocations. I found that mockingbirds live in a highly transitive hierarchy and that the dominance networks are explained by the age and social status of the individuals. Moreover, the network simulations showed that inadequate harvesting could increase the probability of group disruption in the new area of translocations. My research will help develop a reintroduction strategy for the species to Floreana Island and it will assist the Galápagos National Park to reach a major conservation milestone for the species.

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