German storks turning up with African arrows in their bodies in the early 1800s gave scientists their first hard proof of migration. Two centuries on, trackers, feather chemistry and millions of birdwatcher sightings are finally revealing the full routes, since only 6.5 million of 79 million banded birds were ever recovered.

— via The Conversation — Science, Peter P. Marra, Dean of The Earth Commons, Professor of Biology and the Environment, Georgetown University