Natural behavior performance in captive animals is traditionally utilized as a metric to establish welfare states, with an increase in natural behavior associated with positive welfare. Captive environments, including zoos strive to replicate ecologically relevant environments that promote species-specific, adaptive behavior performance. However, spatial restrictions and complex habitats required by some species create various challenges for zoo staff to implement management and husbandry practices to achieve this. Some species struggle to adapt and cope in captive environments, with increased abnormal behavior performance which may reduce welfare. Other species may adapt to captivity in novel ways, demonstrating flexibility in their behavior patterns without compromising welfare. However, research indicating positive behavioral flexibility in captive animals is sparse. The main aim of this review was to categorize animals as being fully behaviorally flexible, partially behaviorally flexible, or behaviorally inflexible. Effect sizes (Hedges’ g) were calculated to compare behavioral categories of animals in the wild and zoo, grouped by taxonomic Order (Testudines, Primates, Artiodactyla, Psittaciformes and Carnivora) and ecological traits to determine their level of behavioral flexibility. Effect sizes were also analyzed to determine behaviors suggestive of good welfare that were absent in zoo species. Despite variation across all groups, abnormal behavior was consistently highest in zoo animals, with reproductive and foraging behaviors most often compromised. Overall, complete positive behavioral flexibility was suggested in Testudines (potentially a result from temperature variation to maintain homeostasis), completely migratory species who are exposed to heterogenous landscapes when traveling long distances, and for a specific primate, the ring-tailed lemur (Lemur catta) potentially to improve resource access due to their terrestrial nature. All other groups evaluated demonstrated partial behavioral flexibility or behavioral inflexibility. Abnormal behavior prevalence and reduced foraging and reproductive behaviors in these groups suggests an inability to adapt to captivity. This necessitates more focused investigations that identify environmental features or aspects of managed environments that can meet a species’ needs in the zoo.

Zoo enclosure design, and housing and husbandry protocols, will always be a compromise between what a species has evolved to do and what is possible to offer in a human-created environment. For some species, behaviours that are commonly performed in the wild may be constrained by husbandry practices that are used for ease or aesthetics or are accepted conventions. As zoos place more emphasis on positive animal welfare states, zoo enclosures should be scrutinised to check that what is provided, in terms of useful space, appropriate replication of habitat features, and maximal potential for natural behaviour performance, is relevant to the species and individuals being housed. For some species, zoos need to grapple with tough questions where the answer may not seem immediately obvious to ensure they are continuously improving standards of care, opportunities for the performance of species-typical behaviours, and advancing the attainment of positive welfare states. Determining the importance of flight, for example, and what this behaviour adds to the quality of life of a zoo-housed bird, is an important question that needs addressing to truly advance aviculture and how we determine bird welfare. This paper provides questions that should be answered and poses measures of what flight means to a bird, to provide evidence for the development and evolution of zoo bird housing. If we can devise some way of asking the animals in our care what they need, we can more firmly support decisions made that surround enclosure design, and housing decisions. Ultimately, this means gathering evidence on whether birds like to fly (e.g., from birds in training or demonstration activities) by applying mixed methods approaches of behavioural analysis, data on wild ecology, qualitative behavioural assessment, and cognitive bias testing to develop a robust suite of tools to address avian welfare considerations. Avian welfare scientists should attempt to define what meaningful flight is (i.e., flight that truly suggests a bird is flying) in order to support guidelines on aviary dimensions, space allowance, and welfare outputs from birds in both flighted and flight-restricted populations, and to determine what is most appropriate for an individual species. Changing the term “best practice” husbandry guidelines to “better practice” husbandry guidelines would instil the importance of regular review and reassessment of housing and management suitability for a species to ensure such care regimes remain appropriate. With an increasingly welfare-savvy public visiting zoos, it is essential that we seek more evidence to support and justify how birds are kept and ultimately use such evidence to enact changes to practices that are shown to infringe on avian welfare.

Understanding animal behaviour can feel like deciphering a foreign language. In 1963, pioneering ethologist Nikolaas Tinbergen offered a key: four fundamental questions to dissect behaviour’s complexities and reduce interpretive bias. These “Four Questions” fall into two categories: Proximate (how?) and Ultimate (why?). The Proximate questions ask how the behaviour is triggered (Causation) and develops over time (Ontogeny). The Ultimate questions delve into its evolutionary history (Phylogeny) and purpose (Function). Traditionally used in behavioural ecology, Tinbergen’s framework finds new relevance in fields like sentience, welfare, conservation, and animal management. This paper illustrates how further integration of these Questions into applied research can improve outcomes. For example, captive animals can receive enrichment seemingly “unnatural” in origin and form. Does such enrichment trigger species-typical behaviours, fulfilling the same adaptive function as natural stimuli would? Understanding a species’ natural behaviour patterns and how the performance of such activities promotes positive welfare states is key to biologically relevant population management. Tinbergen’s Four Questions can help scientists to decipher the relevance of natural behaviour, and how a species’ responses to their environment indicate what individuals need and want at a specific time or place. By applying the Four Questions, we can answer this question and, in turn, refine husbandry practices and conserve behavioural diversity in managed populations. Sixty years after their conception, Tinbergen’s Four Questions remain a powerful tool for behavioural research. By embracing different biological disciplines within a unified framework, applied animal zoo science will continue to advance and provide credible evidence-based outputs.

This paper addresses the potential for technology to support husbandry and enrichment opportunities that enhance the welfare of zoo and sanctuary-housed nocturnal and crepuscular species. This topic was investigated through the medium of a multidisciplinary workshop (Moon Jam) that brought together species experts, zoo designers, Animal-Computer Interaction researchers and post-graduate students in collaborative discussions and design sessions. We explain the context through an examination of existing research and current practices, and report on specific challenges raised and addressed during the Moon Jam, highlighting and discussing key themes that emerged. Finally, we offer a set of guidelines to support the integration of technology into the design of animal husbandry and enrichment that support wellbeing, to advance the best practices in keeping and managing nocturnal and crepuscular animals.

This paper derives B-values from first principles and compares them with the B-values of the GPS Local Area Augmentation System (LAAS). We begin with the linear model for the reference receiver architecture of the ground reference station. From this linear model we derive the optimum estimates and optimum tests. The optimum B-values are the residuals of the linear model. Using the minimum mean square error (MSE) as the performance criterion allows us to calculate the optimum residuals. We call these optimum linear model residuals the linear model B-values. We also show that the difference in MSE between the linear model B-values and the LAAS B-values is not significant. Thus the linear model B-values support the choice of the LAAS B-value algorithm. Most surprisingly, the LAAS B-value algorithm for cov(e) = s̀²I is identical to the residual test statistics used by the receiver autonomous integrity monitoring (RAIM) algorithm in unaugmented GPS.

The performance of natural behaviour in captive animals can be used to indicate welfare, with an increase in natural behaviour suggesting positive welfare, and a decrease in natural behaviour signifying welfare compromise. Due to policy and legislative requirements, zoos often use non-invasive methods to assess welfare, such as behavioural observations. However, the validity of such measures has been questioned, with some natural behaviours (including predator avoidance) potentially inducing stress and compromising welfare. The concept of “natural living”, or the provision of opportunities to perform species-specific behaviour, is used as an approach to assess behavioural diversity, a method to quantify the number and frequency of natural behaviours to determine welfare states. To better understand the appropriateness of natural behaviours in captive animals, we must continue to research species’ natural history, particularly under-represented but common zoo species such as birds, reptiles, and fish. Further, comparisons of baseline time-activity budgets in zoo-housed animals with their wild counterparts may indicate how behavioural flexibility in captive environments, or adaptation to novel stimuli not present in the wild may also serve to indicate welfare states. Natural behaviours can also help to establish the ecological relevance of the zoo enclosure and its biological resources to meet animal needs. Thus, through utilising a range of behavioural measures, in combination with reliable data on species’ natural history, informed assessments of welfare can be made to ensure that the needs of zoo-housed animals are met. <!----> <!----> <!----> <!---->