Investigating individual and social behaviour of the Northern bald ibis (Geronticus eremita): behavioural variety and welfare.

Caterina Spiezio,Valentina Valsecchi,Camillo Sandri,Barbara Regaiolli

doi:10.7717/peerj.5436

Caterina Spiezio, Valentina Valsecchi + Show 2 more

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https://doi.org/10.7717/peerj.5436

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Abstract

The Northern bald ibis (Geronticus eremita) (NBI) is one of the most threatened birds in the world. Intense conservation efforts have been undertaken and several research projects on the species are being done in Morocco and in Europe. Observing animal behaviour has been proved to be an efficient and non-invasive technique to assess the animal welfare, with the performance of a wide array of natural behaviours being one of the mostly used indicators of good mental and physical well-being. The aim of this study was to investigate the behaviour of a flock of 14 zoo-living NBI of different ages. The study focused on the variety of species-specific individual and social behaviours, in the light of reintroduction of the study juveniles in the wild. Per subject, 20 10-min. sessions were done. A continuous focal animal sampling method was used to collect individual and social behaviours. Behavioural data have been compared between adults and juveniles. Moreover, a Behavioural Variety Index (BVI) has been proposed and calculated based on previous literature describing natural ibis behaviours. The BVI might help in the evaluation of the variety of behaviours performed by each individual and the monitoring of the diversity of the behavioural repertoire of zoo animals. Our results showed that the birds performed species-specific behaviours and no abnormal behaviour was reported. Moreover, the BVI highlighted a good behavioural variety as each bird performed approximately 78% of the natural behaviours described in the Northern bald ibis and in close relative species. Our findings seem to suggest the presence of qualitative and quantitative similarities between the behavioural repertoires of the study ibises and those described in wild conspecifics, suggesting a good welfare of the colony. Finally, the BVI proposed in the current study seems to be a useful and practical tool to test behavioural diversity in zoo animals.

Highlights

The Northern bald ibis (Geronticus eremita) (NBI) is listed as Critically Endangered in the IUCN Red List of species and is one of the most threatened birds in the world (Brindley etHow to cite this article Spiezio et al (2018), Investigating individual and social behaviour of the Northern bald ibis (Geronticus eremita): behavioural variety and welfare
To evaluate the welfare of the study NBI, we developed and tested a Behavioural Variety Index (BVI), by revisiting the Hygiene Index described in the study of Webb et al (2006)
Together with the absence of abnormal behaviour, this suggests a good welfare of the colony, even if other parameters need to be evaluated

Summary

Introduction

The Northern bald ibis (Geronticus eremita) (NBI) is listed as Critically Endangered in the IUCN Red List of species and is one of the most threatened birds in the world (Brindley etHow to cite this article Spiezio et al (2018), Investigating individual and social behaviour of the Northern bald ibis (Geronticus eremita): behavioural variety and welfare. Proyecto Eremita, in Spain and LIFE Northern Bald Ibis—Reason for Hope in Austria are among the most important and efficient reintroduction projects, leading to the creation of resident and migrating breeding flocks respectively. Proyecto Eremita aims to establish a sedentary, free-flying colony in Southern Spain through two main steps. A free flying hand-reared group of ibises is established in the area and other juvenile parent-reared birds from zoos are introduced in such group. Juveniles are maintained in an aviary during a period (October –January) for acclimatisation before release This technique facilitates the integration of the new zoo birds into the free-ranging hand-reared group (Quevedo, López & Sánchez, 2017). The study Northern bald ibises were involved in Proyecto Eremita, as juvenile parent-reared birds of the flock were destined for reintroduction in the wild

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