Family: Green-backed gerygone (Gerygone chloronota) belongs to the family Acanthizidae in the genus Gerygone.
Habitat: Green-backed gerygone is confined to the limited pockets of monsoon rainforest in northwestern Australia; it is abundant there. And in the Kimberleys, it extends inland along streams lined with paperbark Melaleuca into eucalypts. It is rather solitary, but is sometimes seen in pairs or with other birds in loose feeding flocks.
In most parts of its range, the green-backed gerygone is sedentary, though it may wander locally when not breeding. At that time, it often enters the mangroves along the coast of Arnhem Land. It seems likely that, as with other gerygones, the female constructs the nest and incubates the eggs with some assistance from the male.
There is usually only one brood a year. The green-backed gerygone builds its nests in the same way as the brown, but, like the white-throated and the fairy, it spends more time shaping the nest cavity. Like the fairy gerygone, the green-backed gerygone often builds its nest near a wasp nest.
Subspecies: Two subspecies are listed below
1. G. c. chloronota, Gould, 1843
2. G. c. darwini, Mathews, 1912
Identification: Both sexes are alike. The head and face are mid-gray-brown; the back and rump are dull yellow-green. The wings are like the back, but the flight feathers are darker grey-brown and the edges are dull yellow-green. The tail is plain grey-brown. The underparts are white, often faintly grey on the throat and washed pale lemon on the flanks. The eyes are rich red. The bill is black. The feet are slate to dark grey. The immature are similar to adults but duller. The eyes are brown. The bill is dark horn.
Vocalizations: The green-backed gerygone call is a rapid, high-pitched twittering reel of whistled notes around the same pitch, repeated over and over. Males and possibly females sing at all times of day throughout the year, but more so when breeding.
Nesting and Breeding: Green-backed Gerygone nesting and breeding occur mainly in October–April but probably also sporadically throughout the year. Nest a rounded, compact oval dome shape with a short tail and a side-entrance hood usually extended into the funnel. The nest is made of bark strips and grasses bound with cobwebs, sparsely adorned with bark and spiders’ egg sacs, lined with vegetable down and sometimes feathers, suspended from a stem among leafy end branchlets of small trees 1–15 meters above ground.
Eggs and Incubation: The bird lays two, usually three eggs; matt white, speckled all over with red-brown, often in a zone at the larger end; oval, about 18 x 13 mm. The incubation period is about 12–13 days, mostly for females. The young left the nest in about 10–11 days.
Distribution: Green-backed Gerygone is found in the pockets of monsoon rainforest and fringing mangroves around Arnhem Land and offshore islands, NT, and inland along paperbark-lined streams to eucalypt gorges in Kimberleys, Western Australia. It is also widespread in Papua New Guinea.
Diet: Green-backed Gerygone feeds vigorously, gleaning insects in the outer foliage of the canopy and leafy middle stages, rarely going close to the ground.
Other Names: It is also known as the Green-backed warbler and Green-backed flyeater
Size: Green-backed Gerygone measures about 90–100 mm in length.
Races: There are about four races, two in Australia.