Smallest organisms
With a mass of approximately and a length of 5 centimetres (2.0 in), the bee hummingbird ("Mellisuga helenae") is the world's smallest bird species and the smallest warm-blooded vertebrate. Called the "zunzún" in its native habitat on Cuba, it is lighter than a Canadian or U.S. penny. It is said that it is "more apt to be mistaken for a bee than a bird". The bee hummingbird eats half its total body mass and drinks eight times its total body mass each day. Its nest is 3 cm across.
Red-shouldered macaw
The red-shouldered macaw ("Diopsittaca nobilis") is a small green South American parrot, a member of a large group of Neotropical parrots called macaws. The species is named for the red coverts on its wings. It is the smallest macaw, being in length. It is native to the tropical lowlands, savannah, and swamplands of Venezuela, the Guianas, Bolivia, Brazil, and far south-eastern Peru. It has two distinct subspecies, the noble macaw and the Hahn's macaw, and a possible poorly distinct third subspecies that has longer wings, but is otherwise similar to the noble macaw. The Hahn's subspecies is named for German zoologist Carl-Wilhelm Hahn, who in 1834 began compiling "Ornithologischer Atlas oder naturgetreue Abbildung und Beschreibung der aussereuropäischen Vögel" (Engl: Ornithological Atlas or natural depiction and description of birds from outside Europe).