Zebra finches are active, noisy, sociable little birds that live wild in Australia but are also popular cage and aviary pets all over the world. In fact, they are almost as popular pets as budgerigars and canaries. There are two subspecies. One is found throughout most of Australia, except for the very north and the very south of the country. The other is found in East Timor, parts of Indonesia, and some coastal areas of Australia. Domesticated zebra finches mostly derive from the Australian subspecies.
Zebra finches may reach five years of age in their natural environment, but can live twice as long as that in captivity. In the wild, zebra finches live in groups on open grasslands where there are some bushes and trees, usually close to water. They also make use of man-made land features, such as watering holes and cultivated fields. Well-adapted to desert conditions, they do not like dense, damp woodlands or forests. They nest in low trees and bushes, in holes, on the ground, in termite hills, rabbit burrows or the nests of other birds, and in crevices and ledges on buildings.
Male and female zebra finches differ in their colouration. Males have bright red beaks, orange cheek patches, black-and-white bars covering the throat down to a black breast bar (this is the pattern that gives them the 'zebra' element in their name), a black 'teardrop extending down from each eye, chestnut-coloured flanks with white spots, and black-and-white tail. Females are grey except for the black teardrops and black-and-white tails, and their beaks are more orange than red. When choosing a mate, hen zebra finches choose males with the reddest beaks, the most symmetrical markings, and which are the most prolific singers. Zebra finches pair for life, but high death rates do lead to frequent re-pairings.
Like budgerigars, canaries and some other domesticated birds, zebra finches in captivity have developed many mutations from the original 'normal' form. For example, 'fawn' zebra finches are light brown in colour where normal birds are grey, and 'whites' are completely colourless, with no markings at all. 'Chestnut-flanked whites' are ivory white, with the same markings as on normal birds. In 'penguin' zebra finches, the top of the head, back and wings are the normal body colour but the underparts are white. And, as their names suggest, the cheeks of the 'black-cheeked' zebra finch are black instead of the usual orange, and the male 'black-breasted' zebra finch has a much larger than normal black bar on its breast.
Male zebra finches are loud and boisterous singers, though their calls are rather squeaky and not very musical. Each bird's song is different: although young birds generally learn their song from their father, they will change it to create their own version, incorporating other sounds they hear around them. Recently, fascinating new information about zebra finch song has been discovered: in hot weather, zebra finches sing special songs to their young in the eggs and these 'incubation calls' affect the chicks' development in the egg. These calls are produced towards the end of the incubation period if the temperature rises above 26°C (78.8°F). Young birds that have listened to these calls are found to weigh less and grow more slowly than other hatchlings, and they cope better in heat. Scientists suggest that, with their smaller body size, such young are better at losing body heat in hot weather.
Zebra Finches have also developed a special method of drinking water, not sucking it up but tipping their bills into the water and using their tongues to scoop it up. In this way, they can drink water quickly and so spend less time at water holes where they are vulnerable to predators. Moreover, this way of drinking allows them to exploit small quantities of water such as dew drops as well as to draw water up from places that would otherwise be difficult to drink from. Zebra finches also eat the leaves of succulent plants as a means of staying hydrated when there is no water supply nearby. Studies have shown that they can survive without water for at least a year, and probably even longer. However, they cannot survive even a day without food. Primarily seed-eaters, they are very messy in their eating habits and drop seeds all around them, which of course helps their food plants to reproduce and so provides more food for the birds. They rarely eat insects but nevertheless they can catch flying insects in mid-air.
Zebra finches are not only popular pets, they are also widely used in research. In fact, they have been spoken of as the avian equivalent of laboratory rats. No other finch has been studied as closely as the zebra finch. There have been numerous studies of the birds in their natural environment and also laboratory studies of such behaviour as mate-selection and song-learning. Because zebra finches learn their songs from their surroundings, they can be used to investigate the neural bases of learning, memory, and responses to stimuli. The zebra finch genome (the complete set of the bird's genes) was the second bird genome to be fully described, after that of the chicken.
