The spatial structure of natural populations is determined by the degree of interaction of individuals or social groups that occupy different parts of the habitat. The most influential factor in this spatial structuring is individual dispersal behaviour, defined as the movement between site of birth and site of reproduction. The aim of this project is to obtain more insight in the role of environmental variation and social structure in the dispersal process of a model species, the Great Tit. An essential element is the quantification of parameters of individual quality and condition.