Birds are a diverse group of vertebrate animals that have feathers, lay hard-shelled eggs and have strong but light weight bones. They are endothermic which is also known as warm-blooded.
All birds have feathers, but this does not mean that all birds can fly, Australia is home to a number of flightless birds such as the emu, cassowary and penguins.
There are over 9000 species of birds in the world and around 800 of these are found in Australia. There are a large variety of sizes. The smallest bird in the world is a hummingbird that weighs around 2 grams, where the largest is the ostrich weighing in at about 150 kilograms.
Birds can be active throughout the day and night. Species that are active during the day are called diurnal and species that are active during the evening are known as nocturnal.
All birds lay eggs but there are a variety of ways to incubate them and raise the chicks. In many bird species both parents share egg incubation but in some species it is a sole parent that incubates the eggs. This is the case with emus. The male will incubate the eggs for up to 60 days and be the sole parent of the chicks for up to two years. Then there are the birds that don’t sit on their eggs to incubate them at all, such as the Malleefowl. This species lays their eggs in a leaf litter mound, when the litter begins to compost it generates the heat required to incubate the eggs and the parents will adjust the mound daily to ensure the correct temperatures are being maintained.