Simply FOLLOW THIS LINK to the National Audobon Society download page. Then scroll down to the bird image \ you wish to download. From there you will find a “Download high-resolution file” link in the right column.
After you click the “Download high-resolution file”, you will be prompted to create a free user account. You will also have the option to sign-up to receive their free monthly e-newsletter.
The 435 life-size watercolors in the collection were “all reproduced from hand-engraved plates, and is considered to be the archetype of wildlife illustration.” Each image’s web page is accompanied by Audubon’s wonderful first-person descriptions of the animal.