Mary Oliver notices so many things and in such detail. I often see egrets here, same as herons, but never once thought of them as a dropped cloud, such a fitting image, and I do imagine them sometimes writing their own poems. Another of her poems I think compares them to old monks wrapped in white robes, and that is often what I think of them when I see them standing so still at the water's edge.
I have become so enamored by Oliver's descriptions that when I see the birds the words 'egrets' and 'herons' pop in my head only after whatever description I've last read by her. By the way, you should get your blog up and going again. I enjoyed reading your older posts.