False Sunbirds and Asities: Philepittidae

Asities are energetic, lively birds that seem to have little fear of anything around them, including humankind. Some will approach within a few feet of a human being, show a few quick threat displays, then fly off.

Philepittidae singing is simple and not especially loud. Male birds, in flight, can also make fairly loud whirring sounds with their wings. The tenth primary feather of each wing is pointed, and the extended shape creates the sound during flight. A male asity, by adjusting the position of the tenth primary feather, can turn the whirring sound on and off as he wants to. Males use the noise in courtship and defense displays.

Mating behavior in asities is centered on a social behavior system called a polygynous (puh-LIH-juh-nus) lek. One to five males display on vertical branches in an open area twenty to thirty meters across. The males go through several ritualistic displays, competing with others in the lek for the attention and approval of the females. In the most distinctive display, a male will bob up and down on its legs, feet still gripping the branch, while quickly opening and closing the wings. Females gather to watch the displays, each female choosing a male mating partner based on how attracted she is by his courting displays.

In the velvet asity, only females build nests and breeding partners do not form pair-bonds. The other species do establish pair-bonds, and males and females share nest building. A female or breeding pair builds a distinctive, spindle-shaped nest, made from moss, spider webs and plant fibers, suspended from a lower tree branch. The nest, which takes ten or more days to build, is about 10 inches (25 centimeters) in height and 5 inches (12 centimeters) wide. The female lays up to three eggs.