Territory...

Much like humans, birds tend to be socially monogamous: they find  partner to mate with and remain socially exclusive with this partner. 

But, also much like humans, they are often cheat on their partners, or separate to mate with someone else and this often happens when the social partnership is not optimal.

The mating choices of birds are naturally affected by their social environment, because it determines the number and availability of potential partners they can choose from.  

The researchers have studied a breeding population of great tits.   

The results show that male birds with a high proportion of female acquaintances are less likely to divorce their partner between breeding seasons. Interestingly, the absolute number of female associates isn’t important — just the ratio of females to males in the social group. The results also show that males are less likely to divorce if the strength of the association with their partner is higher than their association with other females, and if they are experienced breeders.

'In great tits, males hold territories,' . 'That means that females that divorce their males also change territory. We wonder if females might pay more attention to the territory they want to live in than the social dynamics of the group when it comes to changing partners.'