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 .
Least sandpiper
The least sandpiper ("Calidris minutilla") is the smallest shorebird. The genus name is from Ancient Greek "kalidris" or "skalidris", a term used by Aristotle for some grey-coloured waterside birds. The specific "minutilla" is Medieval Latin for "very small".