Food sharing has attracted much attention because of its apparently altruistic nature and its link to prosociality. However, food sharing has been mostly studied in a reproductive context, during courtship and parental care, where the fitness benefits are obvious. We still lack a clear understanding of the functions of food sharing outside any reproductive context and within social groups of same‐aged peers. Previous studies suggest that cofeeding, the action to let another animal feed from the same monopolizable food source, may be used to build and strengthen bonds between individuals. This may be particularly crucial in social birds forming long‐term associations between mates or siblings such as psittacids and corvids. Here, we investigated food sharing and affiliative behaviors such as allopreening in a psittacine species, namely in a group of captive juvenile cockatiels (Nymphicus hollandicus) consisting of five siblings and five unrelated birds. Our main objective was to study the developmental pattern of food sharing over time and its implication in social bonding depending on kinship, affiliation, and sex. Studying cockatiels in this context is providing many new information since most of the studies on food sharing in birds focused on corvids. We found that, contrary to jackdaws, cockatiels continued to share food with multiple individuals, although the frequency of cofeeding as well as the number of cofeeding partners decreased over time. Cockatiels shared more food with their siblings than with other conspecifics but they were not more likely to do cofeeding with birds of the opposite sex. We also found evidence that young cockatiels exchanged more food with those from whom they received food (reciprocity) and, to a lesser extent, allopreening (interchange), than from other cockatiels. Our findings suggest that in cockatiels, food sharing within social groups serves the formation (and maintenance) of affiliative bonds, especially between siblings, rather than pair bonds, but might additionally be explained by reciprocity, interchange, and harassment avoidance.

An interest in producing sounds during play behaviour might be a forerunner for music. Thus, we explored object play behaviour involving sounds in cockatiels (Nymphicus hollandicus). We provided them with several objects producing sounds and recorded sound production, spontaneous warbles and drumming during breeding, pre- and post-breeding. Birds manipulated the objects in a playful way. They manipulated them less during breeding than during pre- and post-breeding, but the proportion of manipulations producing sounds were higher during post-breeding and breeding than during pre-breeding. Males manipulated the objects more frequently and produced more sounds than females. Youngsters manipulated the objects more than adults. One bird repeatedly put a bell on a xylophone; we discuss several possible explanations for the behaviour, including tool use. Only males warbled and drummed, and during breeding only. Our results suggest an enriching effect of the objects on the birds. Many aspects of musicality remain to be studied.

La musicalité (i.e. l'ensemble des capacités associées à la perception, à l'appréciation et la production musicale) est largement répandue chez notre espèce. Selon certains chercheurs, elle aurait évolué car elle favoriserait la survie et/ou la reproduction. Ainsi, les origines biologiques de la musicalité ont été étudiées dans la littérature, chez l'espèce humaine mais aussi chez d'autres espèces. Les études suggèrent des fonctions adaptatives, dont l'attractivité en tant que partenaire de reproduction, la communication mère-bébé, ou encore la cohésion des groupes sociaux. Dans cette revue comparative, nous présenterons les données existantes sur la musicalité chez les espèces humaine et non-humaines pour chacune des fonctions évoquées ci-dessus. Nous discuterons ensuite la convergence évolutive de la musicalité chez certaines espèces ainsi que son origine biologique.