This species is endemic to south-eastern Australia, mostly being found in north-eastern Victoria, along the western slopes of the Great Dividing Range, New South Wales, and the central coast of New South Wales.
These birds are 20-24 cm long and have a wingspan of 30 cm. They weigh 40-45 g.
The regent honeyeater is usually found within box-ironbark eucalypt associations, seeming to prefer wetter, more fertile lowland sites. It also uses riparian forests of river she-oak Casuarina cunninghamiana and wet lowland coastal forests dominated by swamp mahogany Eucalyptus robusta or spotted gum Corymbia maculata.
They mostly feed on nectar and other plant sugars. They can also feed on insects and spiders, as well as native and cultivated fruits. Nectar is taken mainly from a variety of eucalypt species, especially mugga ironbark, yellow box, white box and yellow gum, and often from mistletoes like the needle-leaf mistletoe and the box mistletoe Amyema miquelii, but also from other plants, both native (Acacia, Banksia and Grevillea) and introduced (Fuchsia and Prunus).
The regent honeyeater breeds in May-March, with a peak in September-November, nesting in individual pairs or, sometimes, in loose colonies. The cup-shaped nests are generally composed of strips of bark and dry grass bound with spider web, usually placed toward the end of large, usually horizontal branches on the crown of an eucalypt up to 20 m above the ground. There the female lays 2-3 pinkish to reddish-buff eggs, which she incubates alone for 12-15 days. The chicks are fed by both parents and fledge 13-17 days after hatching, but remain dependent on their parents for another 3-4 weeks.
IUCN status – EN (Endangered)
This species has a small and fragmented breeding range, and the global population size is estimated at just 1.500 individuals. About 75% of its habitat has been cleared for agriculture and residential development, and remaining habitat is fragmented and continues to decline in quality, thus the population is suspected to be in decline, although the rate of decline has not been estimated. Habitat fragmentation has apparently advantaged more aggressive honeyeaters, particularly the noisy miner Manorina melanocephala, which may be excluding regent honeyeater from some areas.