These hand colored engravings are part of a series of natural history illustrations from "Historie Naturelle Des Oiseaux" edited by George Louis Leclerc de Bufforn, the founder of the Natural History Museum in Paris and engraved by French illustrator Francois-Nicholas Martinet. The series was published between 1770-1786. The engraving with two birds is titled "Merle Olive" (Olive Thrush), and the single bird is titled "Der Klippenkak" (Rock Cocks). Both are attached mounted to custom ecru mattes and are in gilt wood frames. Prints (inside mattes)3 1/8 in. x 5/1/2 in. Frames: 9 3/8 in. x 11 1/8 in.