One of my favorite artists and authors is John Muir Law. I have his first book, Law's Guide to Drawing Birds, and patiently waiting for his new book to be released, which you can pre-order through Amazon, Law's Guide to Nature Drawing and Journaling.
UPDATE: I'm REALLY excited now for the release of John's new book after Cathy Johnson let me know this morning that she's seen it in production and it's WONDERFUL!!!
In addition to the book I presently have, I follow his posts to his website at www.johnmuirlaws.com. One of his recent posts was a step by step on drawing a wren.
I'm not accustomed to drawing by using basic shapes and find it a bit challenging if not awkward. And because of that, I occasionally like to try that technique hoping to hone my skills. Here is a study I just worked based on his post.
Worked in the Hand.book.