This film released by National Geographic explains the ability of aeroplanes to create migration, but never mind that, the music is beautiful, the photography stunning. I suggested viewing this when I had first seen it, now available in full on Youtube. If you have forty-five minutes spare, and wish to hear a wonderful narration with numerous astounding facts, watch this.
https://youtu.be/catNMcxQRTo?si=toFqJ_tTwiO1GXo7