Ron sent me this drawing, along with its reference, to ask for my comment. Well.... it's really well studied and very close to the reference. And that's not an ideal approach.
It is not, however, a perfect copy, so that's definitely in its favour. Ron has obviously interpreted most of what he could see but, in my opinion, not taken that concept quite far enough.
The treatment of the feathers is superb. The cuts through the dark bar markings are sufficient to tell us it's a covering of feathers. The markings themselves are again interpreted, but they are sufficiently similar to the reference to make the same sense while not being carbon copies.
The eyes are looking great! Again, because Ron has exaggerated and improved the contrast within them. The highlights and reflections shine more brightly, while still maintaining the feeling of the original.
Where I'd like to see a different approach is in the lighting... This is Ron's drawing on the left, and my suggested changes on the right.
1: This is the shadow cast by the head on the shoulder, so it makes sense for the right-hand side of the head to also be in the shade. The reference does show that, but very subtly, which suggests it was being illuminated by reflected light from outside the photo. Also, your drawing contains values in this shaded area that match the brighter areas. Dull those down to make the shadow more obvious.
2: Restoring the shade on that side of the head improves the roundness of its three-dimensional form. And, coincidentally, brightens the eye's highlight.
3: In the same vein, the top of the folded wing is also lacking solidity and roundness. Restoring it brings it forward, which adds depth to the drawing.
4: Applying the same shading to the breast pushes the wing even further towards us. And allowing a bright highlight to remain along the edge of the wing emphasises the sharp break between wing and body.
5: Then applying the same thinking to this wing, pushes the chest forwards, adding even more depth.
So, I think it's an excellent drawing that just needs more three-dimensional oooommmph!
Even though Ron was fairly free with his interpretation, I think he was too locked in to the reference as far as the lighting was concerned. Ultimately, what matters is your drawing and what it has to say, and not how faithful it might be to the reference.
