Illustration by Charles-Alexandre Lesueur, based on life-drawings made during Baudin's journey and specimens kept at Jardin des Plantes. The animals were thought to be a male and female of the same species, but are now believed to be a Kangaroo Island emu and King Island emu.

Description
"Black Emus of Kangaroo Island".
The large bird is thought to be based on a Kangaroo Island emu, and the small one on the King Island emu, but were thought to be a male and female of the same species at the time. http://www.euppublishing.com/doi/abs/10.3366/E0260954109001661
The original hand coloured copper engraving was engraved by F. Lambert after paintings and drawings by Charles-Alexandre Lesueur who was the offical artist of natural history on the Nicholas Baudin Voyage 1800-1804 for 'Péron, François (1775-1810). Voyage de découvertes aux terres Australes ..., sur les corvettes le Géographe, le Naturaliste, et al goëlette la Casuarina, pendant les années 1800, 1801, 1802, 1803 et 1804. Paris: De L'Imprimerie impériale, 1807-16.
Date 1808-1811
Source http://www.flickr.com/photos/biodivlibrary/7979797856/in/set-72157631519809640
Author Charles-Alexandre Lesueur, F. Lambert
Source: https://en.wikipedia.org/wiki/File:Baudin_emus.jpg

Kangaroo Island emu or dwarf emu (Dromaius baudinianus) is an extinct member of the bird family Dromaiidae. It was restricted to Kangaroo Island, South Australia, which was known as Ile Decrés by the members of the Baudin expedition. It differed from the mainland emu mainly in its smaller size. The species became extinct by about 1827.

The King Island emu (Dromaius novaehollandiae minor) is an extinct subspecies of emu that was endemic to King Island, which is situated in the Bass Strait between mainland Australia and Tasmania.