1) A bit nervous, but tried tom look closely and draw what I see. Once I looked at how the bird is located on the branch and how the different body parts are in relation to each other it was a bit easier to get the dimensions. Found it difficult to get the lichen and the shading on the leaves.
2) Probably wouldn't have noticed the fringed feathers, and the different shadings - just see more of the whole and register that without looking specifically at each part. Yes I think it is easy to just register the image rather than looking at how all the subparts of the image are in relation to each other and how they overlap - it is more likely that a phot is seen as one or two dimensional.