Selection-based biodiversity at a small spatial scale in a low-dispersing insular bird

The blue tit is a highly mobile small passerine found in deciduous and ever green oaks. In mainland populations, gene flow results in Local maladaptive timing of breeding in evergreen oak forests, the rarer habitat. However, o n the island of Corsica, two populations only 25 kilometers apart are highl y specialized and differ between the two habitat types in breeding and morp hological traits. In contrast to theoretical predictions about the homogeni zing effects of gene flow, this highlights evolutionary consequences of hab itat diversification and isolation at a small spatial scale in insular orga nisms, which should be taken into account in conservation policies.