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.
Buttonquail
The buttonquails are a group of small terrestrial birds. The smallest species is the quail-plover, the only species in the genus "Ortyxelos", which is in length and weighs only . The buttonquails in the genus "Turnix" range from in length and weigh between . They superficially resemble the true quails of the genus "Coturnix", but differ from them in lacking a hind toe and a crop. The females of this family also possess a unique vocal organ created by an enlarged trachea and inflatable bulb in the oesophagus, which they use to produce a booming call.