Scientists discover guidance system for migratory songbirds (news.exeter.ac.uk)

So the Earth's magnetic poles are not involved at all then?

Am I crazy? This doesn't actually say anything about their guidance system? Just that its "genetic"?

> In a groundbreaking new study published in the journal Science, researchers have found that a combination of genetics and environment determines where migratory birds fly to for the winter.

> The research team used incredibly light data logger trackers measuring light intensity and time fitted as backpacks to the birds.

No GPS?