nambroth:

Wing anatomy reference photos (note: artists!)
This is a white Mandarin Duck during his molt. He has shed his flight feathers (primary and secondary feathers) and is growing them back in. They are still pinfeathers. If you are not familiar with pinfeathers, they are the stick-like stage of feathers where blood is still nourishing the growth of the feather proteins (like the beds of your fingernails, sorta!). Photos of this stage can be helpful to people trying to learn wing anatomy because the origins of these major flight feathers is clear on the wing structure.
Here is a diagram of their attachment points to the bird’s skeleton*:

Hopefully these photos are helpful to those learning, especially given the challenging angle/pose that these photos represent!

*Note that some seabirds are really weird and might confuse you here because what even are albatrosses