Hummingbird
Hummingbirds are birds native to the Americas and constitute the biological family Trochilidae. They are among the smallest of birds, most species measuring in length. Indeed, the smallest extant bird species is a hummingbird, the bee hummingbird weighing less than .
Inaccessible Island rail
The Inaccessible Island rail ("Atlantisia rogersi") is a small bird of the rail family, Rallidae. It is the only species in the genus Atlantisia. Endemic to Inaccessible Island in the Tristan Archipelago in the isolated south Atlantic, it is notable for being the smallest extant flightless bird in the world. The species was described by physician Percy Lowe in 1923 but had first come to the attention of scientists 50 years earlier. The Inaccessible Island rail's affinities were a long-standing mystery; in 2018 its closest relative was identified as the South American dot-winged crake ("Porzana spiloptera"), both of which are nested within the genus "Laterallus".