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An emerging hypothesis of animal personality posits that animals choose the habitat that best fits their personality, and that the match between habitat and personality can facilitate population differentiation, and eventually speciation. However, behavioural plasticity and the adjustment of behaviours to new environments have been a classical explanation for such matching patterns. Using a population of dunnocks (Prunella modularis), we empirically tested whether personality or behavioural plasticity is responsible for the nonrandom distribution of shy and bold individuals in a heterogeneous environment. We found evidence for bold individuals settling in areas with high human disturbance, but also that birds became bolder with increasing age. Importantly, personality primarily determines the distribution of individuals, and behavioural adjustment over time contributes very little to the observed patterns. We cannot, however, exclude a possibility of very early behavioural plasticity (a type of developmental plasticity) shaping whatwe refer to as 'personality'. Nonetheless, our findings highlight the role personality plays in shaping population structure, lending support to the theory of personalitymediated speciation. Moreover, personality-matching habitat choice has important implications for population management and conservation. [ABSTRACT FROM AUTHOR]

Consistent individual differences in hormone levels and metabolic rates have been proposed to be potential state variables underlying consistent individual differences in behaviour (i.e. animal personality). However, it remains unclear whether either one alone or both of these potential state variables could be an underlying driver of animal personality., We address this question using meta-analyses of published data from bird species. We hypothesized that state variables that mediate individual differences in behaviour would display similar or higher repeatability estimates than behavioural traits. To test this hypothesis, we quantified repeatability estimates of hormone levels, metabolic rates and behavioural traits., We found moderate to high mean repeatability estimates for both metabolic rates and behavioural traits, but low repeatability estimates for hormone levels. These findings indicate that metabolic rates likely represent an important mechanism for generating adaptive personality differences in behaviour., We also show that: (i) for hormones and behaviour, repeatability decreased with increasing interval time between two measurements; (ii) males and females differed in repeatability for behavioural traits; (iii) stress-induced hormone levels were more repeatable than baseline levels., Future studies are now required to determine the direction of the association between metabolic rates and behavioural traits. At the same time, these studies should try to investigate which of the proposed mechanisms is responsible for the relationship between state variable and state-dependent behaviour., In addition, we encourage researchers to report the coefficient of variation for between-individual variance ( CVB) along with repeatability estimates because these two indices carry different information. We discuss how CVB may better facilitate future comparative studies, including meta-analyses., A is available for this article. [ABSTRACT FROM AUTHOR]

Cooperation is a prevailing feature of many animal systems. Coalitionary aggression, where a group of individuals engages in coordinated behaviour to the detriment of conspecific targets, is a form of cooperation involving complex social interactions. To date, evidence has been dominated by studies in humans and other primates with a clear bias towards studies of male-male coalitions. We here characterize coalitionary aggression behaviour in a group of female carrion crows consisting of recruitment, coordinated chase, and attack. The individual of highest social rank liaised with the second most dominant individual to engage in coordinated chase and attack of a lower ranked crow on several occasions. Despite active intervention by the third most highly ranked individual opposing the offenders, the attack finally resulted in the death of the victim. All individuals were unrelated, of the same sex, and naïve to the behaviour excluding kinship, reproduction, and social learning as possible drivers. Instead, the coalition may reflect a strategy of the dominant individual to secure long-term social benefits. Overall, the study provides evidence that members of the crow family engage in coordinated alliances directed against conspecifics as a possible means to manipulate their social environment. [ABSTRACT FROM AUTHOR]