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 .
Chatham Island merganser
The Chatham Islands merganser is known only from fossils and not much is known about the bird. It was the smallest of all "Mergus" species. Fossil records indicate it was widespread on Chatham Island but not on the smaller nearby islands.