Timing and social dynamics of divorce in wild great tits: A phenomenological approach

Social behaviour is a key part of life for many species. In monogamously
breeding species, social associations between breeding partners are
particularly important. Selection of a breeding partner often begins well
before reproduction, and this process can affect subsequent reproductive
success. Thus, the non-breeding season can shape behaviour during the
breeding season. However, it is currently unknown how breeding season
outcomes can impact associate choice during the non-breeding season, as
studying this requires high volumes of cross-context individual social
data. This study used three years of wild great tit social data from
Wytham Woods, Oxford, UK, to examine social associations between pairs
classified with respect to prior and future breeding status (divorcing,
faithful, new and juvenile). We found distinct patterns of social
association in ’divorcing’ pairs from early winter, suggesting that
divorce is an ongoing behavioural process. Newly forming pairs initially
associated similarly to divorcing pairs, but became similar to faithful
pairs over time. On a finer spatiotemporal scale, the behaviour of
faithful and divorcing birds diverged over the winter. These results
provide the first evidence of a behavioural signature of divorce during
the non-breeding season in great tits, while suggesting that different
behaviours may drive behavioural divorce at different times.