Pointless theorycrafting: How to lose Wingspan in 4 turns
You'll need Oceania and Asia to do it in four turns. Spend one turn getting food, then play the Asian Koel, Brown-Geaded Cowbird, and Horsefield's Bronze-Cuckoo in each habitat. You now have zero egg capacity and no way to play more birds. All you can do is draw bird cards.
Assuming 1 nectar played you will get 9 points for birds, 2 points for nectar at the end of the game, and a max of 7 points if you have Visionary Leader for your bonus card. So 18 points, plus whatever round goals you happen to score on for having birds played.
You'll need Oceania and Asia to do it in four turns. Spend one turn getting food, then play the Asian Koel, Brown-Geaded Cowbird, and Horsefield's Bronze-Cuckoo in each habitat. You now have zero egg capacity and no way to play more birds. All you can do is draw bird cards.
Assuming 1 nectar played you will get 9 points for birds, 2 points for nectar at the end of the game, and a max of 7 points if you have Visionary Leader for your bonus card. So 18 points, plus whatever round goals you happen to score on for having birds played.