I get so many good comments here, and this one in particular has generated an answer that might be useful to others:
Thank you, Body Art. I’ll try to explain- it’s a high-speed approach that catches overall gesture and shape before detail, then refines from there. Street sketching and bird drawing are really similar: they both have moving parts and require a fast hand.
There’s no one method for making a drawing. Every situation poses its own challenges, but here are three tips. Tip 1: draw statues. Depending on the sculptor, they can make for awesome anatomical studies.Tip 2: touch everything a lot. Develop your tactile memory to allow you to “feel” in your mind what you’re drawing on the paper. Pet your dog or your cat for a few minutes, a nice thing to do anyway, and then make a drawing. You’ll have a stronger sense of volume, proportion and, I guess, fur; and a better sense of how an animal is shaped. Tip 3: gesture-draw a two-minute scribble of something- your sleeping dog, your friend, your bicycle- on a regular basis. It will teach you to drop the detail and convey the gist. It also gets your hand/eye up to speed. Set your timer, and go.
Hope that made some sense, and hope it helps!