This gives me the perfect chance to share a fun trivia fact! One of the best ways to link migration patterns were arrows carried by the birds from one area to another. As always, there’s a word for it in German - arrow stork. Even better is that the original specimen is one posted on this map; the white stork!
It was a fun fact until I clicked the link and realized that "arrows carried by the birds" are in fact arrows the birds have been shot with. Interesting history, thanks!
The „Wattenmeer“. During the low tide, there are huge areas with easy to reach food and plenty of areas for birds to rest in with few natural predators.
Also just listing raptors is basically worthless. There are about 40 species of raptors in europe, I guarantee they don't all follow that path. They should have done golden eagles, those are studied pretty well for migration.
I wonder how these change as the climate changes. The Sahara wasn't always desert, and might not be for long going into the future. Probably somebody's modeled it, I should look it up.