The environment is changing rapidly, and it is essential for animals to behaviourally adapt to these changes. In order to adjust their behaviour adaptively they need to collect, retain and use information from their changing environment, processes referred to as cognition. While cognition is known to be important, we still lack information on the existence of consistent cognitive differences across habitat types, suggesting local adaptation in cognitive ability. In order to get this information, we need to investigate whether habitat variation shapes cognitive traits in such a way that individuals are optimized in using information from their local environment and assess the potential for evolutionary change in such traits. In this project, we will determine whether natural variation in habitat quality acts as a potential selection pressure on cognitive variation in great tits, a model species for ecological cognition. For this we will combine cross-foster experiments in a natural population with detailed measures in a controlled captive setup to assess whether wild individuals from varying habitats differ in several cognitive traits under controlled circumstances. We predict that birds from low quality habitats will be better in problem-solving and will show faster learning responses than birds from high quality habitats to match the needs for their habitat. To assess the relative role of hereditary and rearing habitat effects, we will perform a cross-fostering experiment. We predict, besides a moderate genetically determined component, that chicks will develop behavioural characteristics adapted to their rearing habitat. Finally, we will assess the fitness consequences on these cross-fostered chicks by quantifying their recruitment probability and reproductive success. This project will provide novel insights into how habitat variation affects wild birds’ behavioural traits and will be the first to combine observational tests of how habitat quality predicts differences in behaviour with an experimental approach on the development of behavioural and cognitive phenotypes.