anatomy study - notes to myself

These are just a collection of notes to myself from my further research into birds, and thoughts about them about how to or not to incorporate the knew knowledge into my armature design. Sometimes I get a bit carried away perhaps in details and subtleties which would in case this puppet would be for a specific production with a time/budget/etc. limit, and a certain purpose for the functioning of the puppet, not be necessary to figure out. In this case it was interesting and felt meaningful to learn a bit more about anatomy, to also get a better understanding of what I'm trying to achieve with the armature in general.

* primary feathers separate and turn, but secondary feathers don't.
Do they still pivot as a whole though? I designed my wing's  secondary feathers to be able to move and separate though I knew it would need less movement then the primaries, still it seemed necessary to have them able to move somehow during the folding of the wing. It is hard to exactly analyse it when watching moving birds as it is all so much hidden behind/underneath other feathers, etc.

* During a downstroke feathers overlap in such a way that they provide a firm boundary layer that air can't pass. Then, on the upstroke, feathers separate and the wing turns, so that air is flowing straight in between them. (youtube 'how bird wings work (compared to airplane wings) - smarter every day')
My wing design doesn't allow for real twisting of the feathers, at least, I think I would still be able to get enough of this subtle movement with the end of the feathers which will be wire, if necessary.

* Birds have a light tail (mainly feathers, only very short bone part), which makes that their center of gravity is in between the wings.
This is an interesting fact also to think about for the balance of the puppet... It is quite likely that for my puppet the center of gravity, and so also the puppet's balance, will be nearer the wings then the tail. Originally I had planned the rig attachment points to be nearer the hips, as I thought it would make the rig be less in the way with the flapping wings, and easier to hide. But this fact makes me consider again, if I shouldn't place it nearer the wings, so it works better with the balance of the puppet... Maybe I could attach it near the wings, but then let the rod/metal bar go in angle, leading first along the body more downwards, so the point where the rig will be actually attached can still be in a more convenient place to be out of sight. Perhaps I should just leave this decision to the last moment when I have most of the puppet done and can judge it more easily.

* Birds have a compact and centralized bodyplan around their centre of gravity between the wings. The main flight muscles are located at the body midline on the breastbone (which is why birds have large chests).
I'm just wondering now if I made the chest of my bird wide enough... I couldn't figure out exactly how the proportions work. I think together with the shoulders continuing into the wing parts I will have the right proportions, or something close hopefully. 

* Birds have large eyes, the largest part of the skull is reserved for the eye sockets.
Took this into consideration when designing the skull. I may need to make them slightly smaller in order to have the joint at the top of the head for the moving upper eye brows fit in nicely within the proportions without making the head too big.

* Looking at the chest of birds, their 'pectoral girdle' (part with collar bones and chest plate, but separate from rib cage) 'floats' within muscular support separate from the ribcage, so it can slide back and forth over the surface of the ribcage as the motions of flight demand. (Proctor & Lynch, 1993, manual of ornithology)
I found this to be a quite interesting discovery... Would this mean that I can actually never reproduce the full range of movement a wing/bird shoulder can make with my design so far? Would it mean that to actually achieve this it would be necessary to design some sort of chest structure that can move separately from the backbone/rib cage? Of course, at this point I would also need to reconsider what my actual aims are. Which is not to reproduce the exact anatomy and functioning of a real bird, but to make an animated character. In 9 out of 10 situations these sort of subtleties would definitely not be necessary in the puppet. Although my aims are here to create an accurate moving bird armature, this may be a step to skip, perhaps something to have fun with another time. I couldn't help though to have a little fun working out a possible solution, if my rough sketches make any sense:

* In a bird wing the elbow and wrist are in such a way connected that extending the elbow automatically also extends the wrist... This simplifies the co-ordination for the bird.
And also the co-ordination of the animator moving the bird... Good idea, nature is fascinating... But even more complex to build. I think for now I just need to learn coordinating the bird's wing in the right way when animating, but interesting to know, and perhaps consider such kind of mechanisms for any future armature projects...

* flight feathers are asymmetrical: the leading edge is narrower and less flexible the the trailing edge. This is to avoid twisting and damaging and ensures upward bending of the feather during the downstroke.
You can see this of course when looking at feathers, but good to be reminded of, also as it may help the actual functioning of the feathers as well if I design them like this for the puppet too.