A common sight in the rainforests of northeastern Australia is the immaculate sturdybill (Robustirhynchinis imaculatis), a tiny twitavian that feeds almost entirely upon nectar from flowers growing high above the ground. The small, robust beaks of these birds are filled with thousands of bristles that extend from the tongue; an immaculate sturdybill has only to push its head into a flower and open its beak to extract nectar.
Immaculate sturdybills mate for life, generally raising a brood of chicks every third spring. The birds' matrimonial life begins when a suitor shows prospective brides the various nesting locations he has found inside hollow stumps or in shear mudbanks. Males will guide a retinue of females from protential nest to potential nest untill a female either initiates mating at the site of her choice, or all the females fly off to find a male with better real estate.
There is little sexual dimorphism in this species, the male having a slightly larger red spot on the top of his head, and the female having more pronounced brown patches on the nape of her neck. An immaculate sturdybill's normal call is a monotonous repetition of buzzes and rasps. The more melodious mating call (used by a male inviting females to his potential nest site) is heard much less often, and has been likened to "I wonder as I wander."