Genes may lead migrating birds to take particular routes to their destination that could prevent interbreeding, suggests a study that tracked hybrids between songbird species.
Using geolocators that, like GPS, record the position of a bird and allow its long distance movement to be tracked, the researchers found that migration routes may be under genetic control and could be a factor preventing interbreeding.
"This is the first time we have been able to track songbirds over the entire annual cycle, and the data we collected supports a longstanding hypothesis in ecological speciation that differences in migratory behaviour could be acting as post-mating reproductive isolating barriers," said lead author Kira Delmore from University of British Columbia in Canada.
Compared with their parents, hybrids exhibited increased variability in their migratory routes - some used intermediate routes across less suitable areas, while others used the same routes as one parental group on autumn migration and the other on spring migration.
