24 25 1. Social bonds can have important fitness consequences. Although there is increasing 26 evidence that social bonds carry over across contexts, few studies have investigated 27 whether social bonds formed early in life are carried over to adulthood. For example, 28 juveniles of monogamous species go through a major life-history stage transition-pair 29 formation-during which the pair bond becomes a central unit of the social organization. 30 At present, it remains unclear if pair members retain their early-life social bonds after 31pair formation and, if so, when they display these preferences most strongly. 32 2. Here we investigated whether bonds formed early in life carry over into adulthood and 33 whether carry-over was dependent on season, in a monogamous species. Moreover, we 34 investigated the role of familiarity, genetic relatedness and aggression on the 35 perseverance of social bonds. 36 3. We studied the social structure before and after pair formation in captive barnacle geese 37 (Branta leucopsis), a highly social, long-lived, monogamous species. We constructed 38 social networks of groups of geese before pair formation, during the subsequent breeding 39 season, and in the following wintering season. From these networks, we identified the 40 preferred associations among individuals, and how these are carried over during seasonal 41 changes. 42 4. We found that early-life associations in females were lost during the breeding season, 43 but resurfaced during the subsequent wintering season. In males, the early-life 44 associations persisted across both seasons, and were mediated by genetic relatedness and 45 familiarity. The high level of aggressiveness of males, but not females, in the breeding 46 season suggests that males may have played a key role in shaping both their own social 47 environment and that of their female partners. 48 3 5. By taking advantage of a captive population in which animals had no temporal or spatial 49 restrictions to re-associate after pairing and for which we had complete data on their 50 social history, we show that early-life social relationships can be maintained well into 51 later life. Such bonds can be sustained even if they are temporarily disrupted, for example 52 due to reproductive behaviour. Our findings therefore highlight that the early-life social 53 environment can have life-long consequences on individuals' social environment. 54 55 Key-words: aggression, early life, familiarity, genetic relatedness, monogamous, pair 56 formation, social bonds, social networks 57 58 59 Consistency of social bonds affects the extent to which individuals can develop cooperative 60 interactions, build up reputations and form stable dominance hierarchies (Trivers 1971; Axelrod . There is increasing evidence showing that social bonds 65 carry over across time, place, and context. Shizuka et al. (2014) showed that golden-crowned 66 sparrows (Zonotrichia atricapilla) that flocked together in one winter flocked together in the 67 subsequent winter more often than expected ba...