Esmeraldas Woodstar (Chaetocerus berlepschi)

With its striking colors and straight black bill, this 3-inch hummingbird makes up in vividness what it lacks in size — and recognition. Considered rare and uncommon, the Esmeraldas woodstar, whose call is a rapid-fire chit-cheet and chit-chit-cheet, became “range restricted” to two or three disjointed sites in western Ecuador, on the western slope of the Andes.