Juan Fernandez Firecrown

The Juan Fernández firecrown is among the most radically sexually dimorphic hummingbirds. The male and female plumages are so different, and even the female has a male-like iridescent crown, that in the 19th century they were thought to be different species until a nest was discovered with one of each sex. Males are 11.5 to 12 cm (4.5 to 4.7 in) long and weigh about 10.9 g (0.38 oz). Females are about 10.5 cm (4.1 in) long and weigh about 6.8 g (0.24 oz). Both sexes have a straight black bill. The male is almost entirely cinnamon-orange. Voice: The Juan Fernández firecrown's song is "a medley of high-pitched squeaky notes, dry gravelly trills and descending chatters."