A nuber of the paintings carried detailed instructions for Robert Havell Jr.,the English engraver, to guide him and his colorists in the preparation of the copies, notations which were naturally suppressed in the making of the engraved plates. Occasionally the asides were self-critical, as when he inscribed on one painting: “The outer primary of the male bird is pure white, it is dirty in the drawing because the White colour I used happened to be bad.” In the end, John James Audubon was his own most tireless critic; the precise coloration, the sensitive characterizations, and the subtle compositions he achieved in his finished paintings were the result of repeated trials, frequent correction, and at times, ingenious contrivance.
For example, the female peregrine falcon at the right, above, done largely in pastel, was cut out of an earlier drawing and pasted onto paper; the water-color painting of a male bird and a couple of slaughtered ducks was then added. Audubon worked almost incessantly for fourteen days before completing his rendering of the golden eagle to his satisfaction.