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.
The study appeared in the journal Ecology Letters.
