The diminutive hummingbirds display remarkable manoeuvrability in flight, capable of hovering whilst feeding, with up to 200 wing beats per second. Owing to this energy demanding behaviour, hummingbirds feed almost exclusively on nectar, the carbohydrate-rich sugar secretions of plants, and feed from as many as 1,000 to 2,000 flowers each day. Hummingbirds also have the highest oxygen requirement of any vertebrate and, as a result, have uniquely structured lungs that enable them to breathe at a rate of up to 500 breaths per minute. These physiological adaptations have allowed hummingbirds to occupy a vast array of habitats and altitudes throughout the Americas (7).
The mangrove hummingbird mainly feeds from the flowers of the tea mangrove, using its long, specialised tongue to collect nectar at the base of the nectaries. It will also alight upon a perch in the lower or middle levels of the mangrove, and make repeated forays to catch small insects, such as mosquitoes, from the air (2) (4). The mangrove hummingbird breeds between October and February, and, in common with other hummingbirds, males will attract partners with elaborate courtship displays (4) (7). Although aggressive to unknown birds, unlike many other hummingbird species, male mangrove hummingbirds do not appear to defend territories (7) (8). Males probably mate with several females, with each female solely responsible for the construction of the cup shaped nest (4) (7). The nest is typically placed on mangrove twigs, one to four metres above the water, and is constructed with spider web, lichen and plant down. The female is also solely responsible for incubating the clutch of two eggs (4).