Back in 2015, researchers reported observations of strange quail in western mainland Europe and northwest Africa. The birds appeared to be common quail (Coturnix coturnix), but they were larger and had darker throat feathers. They also had rounded wings, a shape associated with less efficient flight, suggesting they may not migrate as far as a common quail should. Common quail are highly mobile animals that migrate thousands of kilometers between Europe and sub-Saharan Africa during the breeding season to increase mating opportunities, but so far, dark morphs have primarily been observed in Southern Europe.
But perhaps the strangest thing about these darker birds is that they exist at all. Usually, different morphs of species arise due to restricted gene flow. Phenotypic divergences might crop up in populations separated geographically, for instance. But with all their moving about—and laying eggs as they go—common quail shouldn’t have any real barriers to gene ...
