Speaker
Description
Migrant birds have species- and population-specific routes linking their distant breeding and wintering grounds. They often show migratory connectivity: birds are not only more similarly timed as others from the same breeding population, but also winter closer together. Yet, it is unknown what determines these shared wintering sites, whilst they are vital to understand migrants’ adaptive capacity. Here, we present a unique tracking study in pied flycatchers (Ficedula hypoleuca), where we not only investigate natural wintering site variation across the breeding range, but also test its causality using an ambitious common garden experiment. Over the course of a five-year experiment, we translocated pied flycatcher females and eggs from the Netherlands to Sweden, hereby creating a free-living population of birds of Dutch, half-Dutch, and Swedish descent in our Swedish study population. By comparing the migratory journeys and destinations of birds from this natural experiment and the common garden experiment, we provide experimental evidence on whether genes and/or natal environment drive between-population variation in migratory timing and wintering sites.
