alt Hacker NewsIt's odd that you can see the borders between Belgium and France for various birds (like the swift and cuckoo), same for the border between Germany and Poland.
I wonder why that is? There are no topological features defining these borders. Maybe the data is normalised in some way across countries?
Replies
_joel • today at 11:02 AM
The birds remained part of the schengen zone and have freedom of movement :)
If this is based on bird spotters, I'd say the national bird spotting organizations don't report or watch for the same birds.