Drawing Brids: Heads, Wings & Feet

When the bird lands in front of you, you must be ready to get the basic form on paper with a few lines. But what do you do then? Once you have this basic shape you are ready to fill in the details but this is hard if you don’t understand what you are seeing. One of the keys to fast field sketching is to understand the structures and features of whatever you are looking at, to know what to expect as the typical way a detail will present, and to have a shorthand way to get that down on paper in a few strokes. Understanding the details and having a tool kit of techniques to get them on paper will make field sketching easier, accurate, and more fun.
How do bird beaks fit into the head? Where should I look for nuance of shape?
How do you draw the eyes?
Wings- this is a biggie, how do you suggest the detail without getting lost in a wing diagram (which you actually don’t see on most birds).
How does the tail attach and how to simplify the shape and angles?
How do I indicate feather texture and groups of feathers?
Whats up with bird feet and how do I draw them?