Species Description
Budgerigars in their natural-habitats of Australia average 18 cm (7 in) long, weigh 30-40 grams, and display a light green body color (abdomen and rumps), while their mantle (back and wing coverts) display pitch-black mantle markings (blackish in fledgelings and immatures) edged in clear yellow undulations. The forehead and face is yellow in adults but with blackish stripes down to the cere in young individuals until they change into their adult plumage around 3-4 months of age. They display small purple patches (called cheek patches) and a series of 3 black spots across each sides of their throats (called throat-spots) of which the 2 outermost throat-spots are situated at the base of each cheek-patches. The tail is cobalt (dark-blue); outside tail feathers display central yellow flashes. Their wings have greenish-black flight feathers and black coverts with yellow fringes along with central yellow flashes which only becomes visible in flight and/or when the wings are stretched. Bills are olive grey and legs blueish-grey, with zygodactyl toes.
Budgerigars in their natural-habitats of Australia are noticeably smaller than those in captivity. This particular parrot species has been bred in many other colors and shades in captivity (i.e. blue, grey, greygreen, pieds, violet, white, yellow...) although they are mostly found in pet stores in blue, green and yellow. Budgerigar plumage is known to fluoresce under ultraviolet light (as most other parrot species do as well), a phenomenon possibly related to courtship and mate selection.
The color of the cere (the area containing the nostrils) differs between the sexes; royal blue in males, pale-brown to white (non-breeding) or brown (breeding) in females and pink in immatures of both sexes (usually of a more even purplish-pink color in young males). Some female budgerigars develop brown cere only during breeding time and later disappears. Young females can often be identified by a subtle chalky whiteness that starts around the cere nostril holes. Males that are either Albino, Dark-Eyed-Clear, Lutino and/or recessive pied (aka Danishpied aka Harlequin) always retain the immature purplish-pink cere color their entire life.
It is usually easy to tell the sex of a Budgie over 6 months old, mainly by the cere colors but behaviors and head shape also help indicate Budgie's genders.
Mature males' ceres are usually light to dark blue but can be purplish to pink in some particular color mutations (DarkEyedClears, Danishpieds aka Recessivepieds and Inos) and usually display much rounder heads. Males are typically cheerful, extroverted, highly flirtatious, most peacefully social and very vocal. Females' ceres are pinkish as immatures and switch from being beigish or whitish outside breeding condition into brown (often with a 'crusty' texture) in breeding condition and usually display flattened back of heads (right above the nape region). Females are typically highly dominant and more socially intolerant.
Habitat
The birds are normally found in small flocks, but can form very large flocks under favourable conditions. The species is extremely nomadic and the movement of the flocks is tied to the availability of food and water.
Distribution
Budgerigars are nomadic birds found in open habitats, primarily in Australian scrubland, open woodland and grassland.