Migrating birds map routes to prevent interbreeding

Migrating birds may be taking particular routes to their destination to prevent interbreeding, a new study suggests.
By tracking hybrids between songbird species, researchers found that migration routes are under genetic control and could be preventing interbreeding.
The research was conducted using geolocators that, like Global Positioning System (GPS), record the position of a bird and allow its long distance movement to be tracked.
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 fall migration and the other on spring migration.

"This is the first time we've been able to track songbirds over the entire annual cycle, and the data we collected support 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 the University of British Columbia, Vancouver.
The research was published in the journal Ecology Letters.