Group living has been proposed to yield benefits that enhance fitness above the level that would be achieved through living as solitary individuals. Dominance hierarchies occur commonly in these social assemblages, and result, by definition, in resources not being evenly distributed between group members. Determinants of rank within a dominance hierarchy can be associated with morphological characteristics, previous experience of the individual, or personality traits such as exploration tendencies. The purpose of this study was to investigate whether greater exploration and positive responses to novel objects in homing pigeons () measured under laboratory conditions were associated with (i) greater initial exploration of the local area around the home loft during spontaneous exploration flights (SEF), (ii) faster and more efficient homing flights when released from further afield, and (iii) whether the traits of greater exploration and more positive responses to novel objects were more likely to be exhibited by the more dominant individuals within the group. There was no relationship between laboratory-based novel object exploration and position within the dominance hierarchy. Pigeons that were neophobic under laboratory conditions did not explore the local area during SEF opportunities. When released from sites further from home, neophobic pigeons took longer routes to home compared to those birds that had not exhibited neophobic traits under laboratory conditions, and had spontaneously explored to a greater extent. The lack of exploration in the neophobic birds is likely to have resulted in the increased costs of homing following release: unfamiliarity with the landscape likely led to the greater distances travelled and less efficient routes taken. Birds that demonstrated a lack of neophobia were not the dominant individuals inside the loft, and thus would have less access to resources such as food and potentially mates. However, a lack of neophobia makes the subordinate position possible, because subordinate birds that incur high travel costs would become calorie restricted and lose condition. Our results address emerging questions linking individual variation in behaviour with energetics and fitness consequences.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'.

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The benefits of dominance are well known and numerous, including first access to resources such as food, mates and nesting sites. Less well studied are the potential costs associated with being dominant. Here, the movement of two flocks of domestic Homing Pigeons Columba livia – measured via accelerometry loggers – was recorded over a period of 2 weeks, during which the birds were confined to their lofts. Movement was then used to calculate each individual's daily overall dynamic body acceleration (ODBA, G), which can be used as a proxy for energy expenditure. The dominance hierarchy of the two flocks was determined via group‐level antagonistic interactions, and had a significantly linear structure. The most dominant bird within each flock was found to move significantly more than conspecifics – on average, c. 39% more than the individual with the next highest degree of movement – indicating a possible cost to possessing the top rank within a hierarchy. Despite the dominance hierarchy being highly linear, this was not the case for ODBA, suggesting that energy expenditure may be more reflective of a despotic hierarchy. These results show the potential for the future use of accelerometry as a tool to study the fusion of energetics and behaviour.

15 16 17 18 19 20 2The benefits of dominance are well known and numerous, including first access to resources 21 such as food, mates and nesting sites. Less well studied are the potential costs associated with 22 being dominant. Here, the movement of two flocks of domestic homing pigeons (Columba 23 livia) -measured via accelerometry loggers -was recorded over a period of two weeks. 24Movement was then used to calculate each individual's daily overall dynamic body 25 acceleration (ODBA, G), which can be used as a proxy for energy expenditure. The 26 dominance hierarchy of the two flocks was determined via group-level antagonistic 27 interactions, and demonstrated a significantly linear structure. The most dominant bird within 28 each flock was found to move significantly more than conspecifics -on average, c.39% 29 greater than the individual with the next highest degree of movement -indicating a possible 30 cost to possessing the top rank within a hierarchy. Despite the dominance hierarchy being 31 linear, mean daily total ODBA did not reflect a linear nature, with no pattern observed 32 between rank and ODBA, once the top ranked individuals had been accounted for. This 33 suggest that energy expenditure may be more reflective of a despotic hierarchy. These results 34show the potential for the future use of accelerometery as a tool to study the fusion of 35 energetics and behaviour. 36 3

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