Abnormal repetitive behaviours in captive birds: a Tinbergian review

A preliminary global investigation into potential impacts on successful captive breeding for two species of Rhyticeros hornbill

Asian hornbills have limited ex situ breeding success, yet these species are some of the most threatened of birds, in need of managed breeding programs. To optimize breeding and increase the sustainability of such populations, it is necessary to assess and improve their husbandry and welfare. Evidence to improve reproduction can be gathered through global husbandry surveys. A survey was sent out to all European Association of Zoos and Aquaria and Association of Zoos and Aquarium holders of the wreathed hornbill (Rhyticeros undulatus) and Papuan hornbill (R. plicatus) to determine predictors for ex situ breeding success. This research found that pairs that have spent more years together (p = .016) and that adding additional proteins to the diet (p = .006) are two significant predictors of breeding success for wreathed- and Papuan hornbill pairs. This paper found a general trend that successful hornbill pairs prefer nest boxes that are situated outside (p = .054). The behaviors of calling to each other and sitting in close proximity showed a general trend and were observed more frequently in successful pairs and, therefore, could be good indicators of bonded pairs. We recommend that ex situ institutions allow their hornbill pairs time to form strong bonds, and that pair compatibility is monitored regularly to ensure that such interactions are positive and not consistently negative. An increase in the percentage of dietary proteins, prior and during the breeding season appears to stimulate pairs to breed. If the management and husbandry alterations presented in this study are implemented, the sustainability of Rhyticeros hornbill populations may be enhanced.

Evaluation of Non-Vector Transmission of Usutu Virus in Domestic Canaries (Serinus canaria)

Usutu virus (USUV) is a flavivirus transmitted to avian species through mosquito bites that causes mass mortalities in wild and captive bird populations. However, several cases of positive dead birds have been recorded during the winter, a vector-free period. To explain how USUV "overwinters", the main hypothesis is bird-to-bird transmission, as shown for the closely related West Nile virus. To address this question, we experimentally challenged canaries with intranasal inoculation of USUV, which led to systemic dissemination of the virus, provided the inoculated dose was sufficient (>102 TCID50). We also highlighted the oronasal excretion of infectious viral particles in infected birds. Next, we co-housed infected birds with naive sentinels, to determine whether onward transmission could be reproduced experimentally. We failed to detect such transmission but demonstrated horizontal transmission by transferring sputum from an infected to a naive canary. In addition, we evaluated the cellular tropism of respiratory mucosa to USUV in vitro using a canary tracheal explant and observed only limited evidence of viral replication. Further research is then needed to assess if and how comparable bird-to-bird transmission occurs in the wild.

Effects of food-based enrichment on enclosure use and behavioral patterns in captive mammalian predators: a case study from an Austrian wildlife park

Background

Combining naturalistic enclosure design and animal welfare with visitor interests and education can be challenging for zoos and wildlife parks. To accomplish both purposes, different types of enrichment (food-based or non-food-based items, such as environmental, sensory, cognitive, social) can be used. The aim of the present study is to investigate the effect of food-based and olfactory enrichments on enclosure use, behavior, and visibility of captive brown bears (Ursus arctos), pine martens (Martes martes), domestic ferrets (Mustela putorius furo), and golden jackals (Canis aureus).

Methods

We used observational approaches to measure enclosure use, behavior, and visibility during three different experimental phases: (1) pre-enrichment (baseline, no experience with the enrichment yet), (2) during enrichment (enrichment was provided at low frequented locations in the enclosures that are easily visible to visitors), and (3) post-enrichment (enrichment was removed from the enclosures).

Results

We found that enrichment led to a uniform use of the enclosure and enhanced visibility in brown bears, increased activity budgets in pine martens, and observed high object interaction in both species. No effects of enrichment were detected in domestic ferrets. Golden jackals did not leave their burrows during daytime during the entire observation period; thus, observations were not possible at all. Our results suggest different effects of food-based enrichment, e.g., enclosure use, temporal activity patterns, and animal visibility. However, further studies should control for the specific role of the factors involved. Our study represents one of the first explorations of food-based enrichment in rather understudied species.

Models of Conditioned Reinforcement and Abnormal Behaviour in Captive Animals

Abnormal behaviours are common in captive animals, and despite a lot of research, the development, maintenance and alleviation of these behaviours are not fully understood. Here, we suggest that conditioned reinforcement can induce sequential dependencies in behaviour that are difficult to infer from direct observation. We develop this hypothesis using recent models of associative learning that include conditioned reinforcement and inborn facets of behaviour, such as predisposed responses and motivational systems. We explore three scenarios in which abnormal behaviour emerges from a combination of associative learning and a mismatch between the captive environment and inborn predispositions. The first model considers how abnormal behaviours, such as locomotor stereotypies, may arise from certain spatial locations acquiring conditioned reinforcement value. The second model shows that conditioned reinforcement can give rise to abnormal behaviour in response to stimuli that regularly precede food or other reinforcers. The third model shows that abnormal behaviour can result from motivational systems being adapted to natural environments that have different temporal structures than the captive environment. We conclude that models including conditioned reinforcement offer an important theoretical insight regarding the complex relationships between captive environments, inborn predispositions, and learning. In the future, this general framework could allow us to further understand and possibly alleviate abnormal behaviours.

The phenotypic costs of captivity

The breeding of threatened species in captivity for release is a central tool in conservation biology. Given gloomy predictions for biodiversity trends in the Anthropocene, captive breeding will play an increasingly important role in preventing future extinctions. Relative to the wild, captive environments drastically alter selection pressures on animals. Phenotypic change in captive animals in response to these altered selection pressures can incur fitness costs post-release, jeopardising their potential contribution to population recovery. We explore the ways in which captive environments can hinder the expression of wild phenotypes. We also stress that the phenotypes of captive-bred animals differ from their wild counterparts in multiple ways that remain poorly understood. We propose five new research questions relating to the impact of captive phenotypes on reintroduction biology. With better use of monitoring and experimental reintroductions, a more robust evidence base should help inform adaptive management and minimise the phenotypic costs of captivity, improving the success of animal reintroductions.

Welfare of broilers on farm

This Scientific Opinion considers the welfare of domestic fowl (Gallus gallus) related to the production of meat (broilers) and includes the keeping of day-old chicks, broiler breeders, and broiler chickens. Currently used husbandry systems in the EU are described. Overall, 19 highly relevant welfare consequences (WCs) were identified based on severity, duration and frequency of occurrence: 'bone lesions', 'cold stress', 'gastro-enteric disorders', 'group stress', 'handling stress', 'heat stress', 'isolation stress', 'inability to perform comfort behaviour', 'inability to perform exploratory or foraging behaviour', 'inability to avoid unwanted sexual behaviour', 'locomotory disorders', 'prolonged hunger', 'prolonged thirst', 'predation stress', 'restriction of movement', 'resting problems', 'sensory under- and overstimulation', 'soft tissue and integument damage' and 'umbilical disorders'. These WCs and their animal-based measures (ABMs) that can identify them are described in detail. A variety of hazards related to the different husbandry systems were identified as well as ABMs for assessing the different WCs. Measures to prevent or correct the hazards and/or mitigate each of the WCs are listed. Recommendations are provided on quantitative or qualitative criteria to answer specific questions on the welfare of broilers and related to genetic selection, temperature, feed and water restriction, use of cages, light, air quality and mutilations in breeders such as beak trimming, de-toeing and comb dubbing. In addition, minimal requirements (e.g. stocking density, group size, nests, provision of litter, perches and platforms, drinkers and feeders, of covered veranda and outdoor range) for an enclosure for keeping broiler chickens (fast-growing, slower-growing and broiler breeders) are recommended. Finally, 'total mortality', 'wounds', 'carcass condemnation' and 'footpad dermatitis' are proposed as indicators for monitoring at slaughter the welfare of broilers on-farm.

Bird Welfare in Zoos and Aquariums: General Insights across Industries

Animal welfare is a priority across accredited zoological institutions; however, historically, research has been prioritized for mammals. Bird-focused studies accounted for less than 10% of welfare research in zoos and aquariums over the last ten years. Due to the lack of scientific publications on bird welfare, zoo scientists and animal practitioners can look to other industries such as agriculture, laboratories, and companion animal research for insight. This qualitative review highlights findings across industries to inform animal care staff and scientists on the welfare needs of birds within zoos and aquariums. Specifically, the review includes an overview of research on different topics and a summary of key findings across nine resources that affect bird welfare. We also highlight areas where additional research is necessary. Future welfare research in zoos and aquariums should prioritize studies that consider a diversity of bird species across topics and work to identify animal-based measures with empirical evidence. Moving forward, research from other industries can help develop innovative research on bird welfare within zoos and aquariums.

Avian cognition and the implications for captive parrot welfare

Previously assumed to be unintelligent animals, many species of birds display high levels of cognition and may even possess conscious awareness. In particular, both corvids and parrots have been the focus of cognitive research including studies on problem-solving, social intelligence, and sentience. Despite their similar neural architecture and cognitive abilities, the laws regarding these two families of birds differ greatly. In the United States, it is illegal to keep corvids as pets. Parrots, however, are one of the most commonly kept pets in America, although their care in captivity remains largely unregulated. Captive parrots suffer from a number of medical and psychological issues and experience high rates of neglect and abandonment. At the same time, wild parrot populations are dwindling due both to habitat loss and capture for the pet trade. This review examines the novel findings on avian cognition and applies them to the potential ethical implications of keeping parrots in captivity. In addition, suggestions for future directions are presented, including the development of legislation to protect captive and wild parrots.

Effects of Key Farm Management Practices on Pullets Welfare—A Review

Simple Summary

Studies on animal behavior and welfare have reported that improving the management practices of pullets can enhance their growth, as well as their physical and mental condition, thus benefiting the productivity of laying hens. Therefore, in this review, we elaborated on the key effective farm management measures, including housing type and matching, flock status, and environmental management and enrichment, to provide the necessary information to incorporate welfare into chicken rearing and its importance in production, with the aim of improving the quantity and quality of chicken products.

Abstract

Studies on animal behavior and welfare have reported that improving the management practices of pullets can enhance their growth, as well as their physical and mental condition, thus benefiting the productivity of laying hens. There is growing confidence in the international community to abandon the conventional practices of “cage-rearing and beak-trimming” to improve the welfare of chickens. Therefore, in this review, we summarized some of the effective poultry management practices that have provided welfare benefits for pullets. The results are as follows: 1. Maintaining similar housing conditions at different periods alleviates fear and discomfort among pullets; 2. Pullets reared under cage-free systems have better physical conditions and temperaments than those reared in cage systems, and they are more suitable to be transferred to similar housing to lay eggs; 3. Improving flock uniformity in appearance and body size has reduced the risk of pecking and injury; 4. Maintaining an appropriate population (40–500 birds) has reduced flock aggressiveness; 5. A combination of 8–10 h of darkness and 5–30 lux of light-intensity exposure via natural or warm white LED light has achieved a welfare–performance balance in pullets. (This varies by age, strain, and activities.); 6. Dark brooders (mimicking mother hens) have alleviated fear and pecking behaviors in pullets; 7. The air quality of the chicken house has been effectively improved by optimizing feed formulation and ventilation, and by reducing fecal accumulation and fermentation; 8. Complex environments (with litter, perches, straw bales, slopes, platforms, outdoor access, etc.) have stimulated the activities of chickens and have produced good welfare effects. In conclusion, the application of comprehensive management strategies has improved the physical and mental health of pullets, which has, in turn, improved the quantity and quality of poultry products.

Casting the Net Widely for Change in Animal Welfare: The Plight of Birds in Zoos, Ex Situ Conservation, and Conservation Fieldwork

Simple Summary

Animal welfare measures have been designed to improve the health and environmental conditions of animals living under human control, for whatever reason. Welfare regulations have evolved also in line with new research insights into the cognitive, affective, and physiological domain of birds, as this paper discusses. This paper casts a critical eye on areas that Animal Welfare regulations have not reached at all, have not gone far enough, or are not regulated or supervised. It identifies the plight of birds living in captivity or being studied in the field, which either by neglect, ignorance, or design are subject to practices and procedures that may not meet basic welfare standards. The paper discusses some profound contradictions in the way we think about birds and their plight in today’s world: marked for extinction on one hand and highly admired as pets on the other; damaging fieldwork on one hand and the aims of conservation on the other. It highlights some common and distressing examples of poor welfare in birds. It also offers some solutions involving simple legislative changes and ways to eliminate some unacceptably low ethical standards in the handling and management of birds.

Abstract

This paper discusses paradoxes in our relationship to and treatment of birds in captive and conservation contexts. The paper identifies modern and new challenges that arise from declining bird numbers worldwide. Such challenges have partly changed zoos into providers of insurance populations specifically for species at risk of extinction. They have also accelerated fieldwork projects, but by using advanced technological tools and in increasing numbers, contradictorily, they may cause serious harm to the very birds studied for conservation purposes. In practice, very few avian species have any notable protection or guarantee of good treatment. The paper first deals with shortcomings of identifying problematic avian behavior in captive birds. It then brings together specific cases of field studies and captive breeding for conservation in which major welfare deficits are identified. Indeed, the paper argues that avian welfare is now an urgent task. This is not just because of declining bird numbers but because of investment in new technologies in field studies that may have introduced additional stressors and put at risk bird survival. While the paper documents a substantial number of peer-reviewed papers criticizing practices counter to modern welfare standards, they have by and large not led to changes in some practices. Some solutions are suggested that could be readily implemented and, to my knowledge, have never been considered under a welfare model before.

Feather Pecking in Non-Beak-Trimmed and Beak-Trimmed Laying Hens on Commercial Farms with Aviaries

Simple Summary

Severe feather pecking (SFP) is a major animal welfare problem in layers. It results in pain and injuries in the affected animal. SFP is a behavioral disorder and should not be confused with aggressive pecking. The aim of our study was to observe the pecking behavior of layers on farms with flock sizes common in practice and to identify possible influencing factors. We found that SFP occurred in all flocks, but the pecking rate varied widely between flocks. A low stocking density and the provision of a winter garden or free range (or both) had a positive effect and reduced SFP. Keeping mixed flocks of brown and white layers was a risk factor for SFP. SFP occurred mainly in the litter area and only rarely on perches. This finding emphasizes the importance of providing enough litter, litter areas and environmental enrichment. Aggressive pecking and SFP were correlated, which may indicate a higher stress level in the flock. Beak trimming reduced pecking rates but did not entirely prevent SFP. Instead of subjecting chicks to this potentially painful procedure, reasons for SFP should be addressed. SFP remains a multifactorial problem, but in recent years, many risk factors have been identified and included in best-practice recommendations, allowing the housing of non-beak-trimmed layers.

Abstract

Severe feather pecking (SFP) is a major animal welfare problem in layers. It results in pain and injuries in the affected animal. It was the aim of this study to gain insight into the actual pecking behavior of laying hens kept on commercial farms with flock sizes common in practice. We observed aggressive pecking and SFP in non-beak-trimmed and beak-trimmed flocks of laying hens and investigated possible influencing factors. The study took place on eight conventional farms in Germany with aviaries, including three farms with a free range and a winter garden, one with a free range and one with a winter garden. Pecking behavior was observed during three observational periods (OPs): OP 1, at the peak of the laying period between the 28th and 33rd week of life; OP 2, in the middle of the laying period between the 42nd and 48th week of life; and OP 3, at the end of the laying period between the 63rd and 68th week of life in one laying period. Videos were analyzed using behavior sampling and continuous recording. We found that SFP occurred in all flocks, but the pecking rate differed significantly between the flocks. SFP correlated positively with the number of hens per square meter of usable area, with statistical significance in the litter area (r = 0.564; p = 0.045). The multivariate analysis revealed that access to a winter garden or free range significantly reduced the SFP rate on perches (p = 0.001). The stocking density (number of birds per usable square meter) had a significant influence on the SPF rate in the nest-box area (p = 0.001). The hybrid line had a significant effect on the SFP rate on perches and in the nest-box area (p = 0.001 each). Lohmann Brown hens in mixed flocks had a higher SFP rate (significant in OP 2) than those in homogeneous flocks, indicating that mixed flocks may be a risk factor for SFP. Lohmann Brown hens pecked significantly less than Dekalb White hens in the litter area (p = 0.010) and in the nest-box area (p = 0.025) and less than Lohmann Selected Leghorn hens in the litter area (p = 0.010). Lohmann Brown and Lohmann Selected Leghorn hens showed increasing SFP rates during the laying period. All hybrid lines had significantly higher SFP rates in the litter area, followed by the nest-box area and perches. These findings emphasize the importance of providing enough litter, litter areas and environmental enrichment. We found a significant positive correlation between aggressive pecking and SFP—in OP 1: rho (Spearman) = 0.580, p < 0.001; OP 2: rho = 0.486, p = 0.002; and OP 3: rho = 0.482, p = 0.002 (n = 39) —indicating that SFP may lead to a higher stress level in the flock. Beak trimming reduced pecking rates but did not entirely prevent SFP. Instead of subjecting chicks to this potentially painful procedure, reasons for SFP should be addressed. In conclusion, our data suggest a positive influence of a lower stocking density and the provision of a winter garden or free range for additional space. The hybrid line had a significant influence on the feather-pecking rate on perches and the nest-box area. Aggressive pecking and severe feather pecking correlated positively. We assume that vigorous and painful AP were an additional stress factor, especially in non-beak-trimmed flocks, leading to more SFP in due course. Beak trimming had a reducing effect on SFP. However, our results showed that non-beak-trimmed flocks could be kept without major outbreaks of SFP.

Romantic Love and Sleep Variations: Potential Proximate Mechanisms and Evolutionary Functions

This article provides a narrative review of what is known about romantic love and sleep variations and provides possible explanations for the association. Romantic love and sleep are described using a comprehensive, unifying framework advocated by Tinbergen. We summarise the findings of studies investigating the relationship between romantic love and sleep. Sleep variations are associated with romantic love in adolescents and young adults. We then detail some proximate mechanisms that may contribute to sleep variations in people experiencing romantic love before considering potential evolutionary functions of sleep variations in people experiencing romantic love. The relationship between symptoms of psychopathology and sleep variations in people experiencing romantic love is described. With the current state of knowledge, it is not possible to determine whether sleep variations associated with romantic love are adaptations or by-products of romantic love. We conclude by proposing areas for future research.

Conducting Behavioural Research in the Zoo: A Guide to Ten Important Methods, Concepts and Theories

Behavioural research in zoos is commonplace and is used in the diagnosis and treatment of potential husbandry and management challenges. Robust methods that allow valid data collection and analysis constitute an evidence-based approach to animal care. Understanding behaviour is essential to improving animal management, and behavioural research is therefore popular, with a wide choice of behavioural methodologies and theories available. This review outlines ten methodological approaches, concepts or theories essential to zoo science that are based around behavioural observation. This list is not exhaustive but aims to define and describe key areas of consideration when planning and implementing a zoo-based behavioural project. We discuss the application of well-established methods (the construction of ethograms, use of time–activity patterns and measurement of space/enclosure use) as well as evaluating newer or less-widely applied analytical techniques, such as behavioural diversity indices, social networks analysis and Qualitative Behavioural Assessment. We also consider the importance of fundamental research methods, the application of pure science to understand and interpret zoo animal behaviour (with a review of a Tinbergian approach) and consideration of meta-analyses. The integration of observational techniques into experiments that aim to identify the cause and effect of behavioural performance is then explored, and we examine the assimilation of behavioural methods used in studies of environmental enrichment. By systematically studying animal behaviour, we can attempt to understand the welfare of individual animals in captivity, and here we present an example of our reviewed approaches to this area of zoo science. Combining multiple methodologies can lead to a greater understanding of behaviour and welfare, creating robust research, progressing husbandry and advancing conservation strategies. Collaborations between zoological collections and academic researchers (e.g., in Higher Education Institutions) can further refine and enhance the validity of research and husbandry practice alike.

A Global Survey of Current Zoo Housing and Husbandry Practices for Fossa: A Preliminary Review

The fossa is a specialized Malagasy carnivore housed in ex situ facilities since the late 19th century. Moderate breeding success has occurred since the 1970s, and welfare issues (notably stereotypic pacing behaviour) are commonly documented. To understand challenges relating to fossa housing and husbandry (H&H) across global facilities and to identify areas of good practice that dovetail with available husbandry standards, a survey was distributed to ZIMS-registered zoos in 2017. Results showed that outdoor housing area and volume varied greatly across facilities, the majority of fossa expressed unnatural behaviours, with pacing behaviour the most frequently observed. All fossa received enrichment, and most had public access restricted to one or two sides of the enclosure. The majority of fossa were locked in/out as part of their daily management and forty-one percent of the fossa surveyed as breeding individuals bred at the zoo. Dense cover within an enclosure, restricted public viewing areas, a variable feeding schedule and limited view of another species from the fossa exhibit appear to reduce the risk of unnatural behavior being performed. The achievement of best practice fossa husbandry may be a challenge due to its specialized ecology, the limited wild information guiding captive care, and the range of housing dimensions and exhibit features provided by zoos that makes identification of standardized practices difficult. We recommended that holders evaluate how and when enrichment is provided and assess what they are providing for environmental complexity as well as consider how the public views their fossa.