You have a very good eye, because I got the water idea from this post by the author of the Kingdom series https://forums.tigsource.com/index.php?topic=40539.msg1104986#msg1104986
Each bird you discover through the journal is based on a real bird: the bird call that sounds when it first unlocks (and every time it spawns thereafter) is from a real bird, and the sprite is drawn from pictures of those birds (with some creative licenses). Unfortunately once you advance the background bird sounds kind of drown the newly spawned birds, so you can only really tell on the first few. Late in development I thought of being able to track which bird is which with the journal, to have a bit more context, but it went way our of scope.
Thank you so much for playing, I'm glad you enjoyed it!