Decoupling of behavioural and morphological differentiation in a partially migratory bird population
Capsule Resident Blackcaps in eastern Spain differ in morphology and isotope profile from central European conspecifics wintering in the area, but not from locally breeding migrants. Aims Natural selection shapes flight morphology in relation to migratory habits. Thus, intraspecific variation in migratory behaviour is often paralleled by morphological differentiation. We test whether differences i