: Socio-ecological factors shape the opportunity for polygyny in a migratory songbird

The dataset contains the information of the pairs breeding in the population during the study years: breeding year (year), identity of the nest box (IDnestbox), its coordinates (GPSLONG & GPSLAT) and number of plot (Plot; there are two plots in the study area) wherein the pair bred. The file also contains the identity of the male (IDmale), the identity of the female (IDfemale), the mating status of the female (Polygyny = scored as 1 for the combination between the polygynous male and the secondary female) and its breeding date (Layingdate = day of the first egg, scored as days after 1st May). . To be published in Behavioral Ecology