During the early age of scientific inquiry in Europe, very few human travelers were following the white stork's migration route (Europe→Anatolia→Levant→Nile→East Africa), and I'd guess that most of those who did were from the Muslim world and not particularly accessible to European observers.

The small number of long-distance travelers and cultural contacts between the Eastern Mediterranean and Western Europe did result in lots of valuable learning; this particular bit of learning just took a while.