Hidden change: cryptic evolution in flycatchers

Documented cases of phenotypic change consistent with heritability estimates and the strength and direction of selection are relatively rare. There are several possible reasons for this paucity, including environmental masking of genetic change. A new paper by Merilä and colleagues documents ‘cryptic evolution’ in a long-term study of collared flycatchers in Sweden, and makes the case for hidden evolutionary change in general.