There are two kookaburra species in Australia, the laughing and the blue-winged. This article refers only to the iconic Lauging Kookaburra.
Kookaburras  (Dacelo novaeguineae) are very large terrestrial kingfishers native to Australia and New Guinea. They are in fact the largest kingfishers in the world.
Laughing kookaburras are found in all of the state capitals except Darwin and occupy much of eastern Australia. They are found in forest, woodland and along watercourses. The populations arund Perth and on islands were introduced.

They are best known for their distinctive and unmistakeable call which does indeed sound like good-natured if rather crazed human laughter. It starts with a chuckling kook-kook-kook and progresses to a rising and falling ka-ka-ka-ka. It is used to demarcate a territory and as a greeting, especially when food arrives from a parent. It is heard at any time of the day from before dawn till after sunset and often other kookaburras will join in so that soon the bush is filled with a raucous laughter.

Kookaburras hunt in much the same way as other kingfishers do: by perching on a convenient branch or wire and waiting patiently for prey to pass by. It will then swoop down and seize the prey, killing it by either crushing it in the beak or, for larger animals, by thrashing it against the branch until it is dead. Prey consists of small mammals amd lizards, small birds and large insects. Most famously it takes snakes (often venomous species) of up to one metre in length.

Kookaburras tend to live in small family units, with offspring helping the parents hunt and care for the next generation of offspring.

The breeding season is from October or November and begins with the male courting the female by offering food for which she will have begged like a juvenile. Breeding will continue into January/February if the first clutch fails. Nesting is usually in a bare tree hollow or in a tunnel in an arboreal termite mound. Three eggs are laid in two day intervals and are incubated by both parents for 29 days. Chicks remain in the nest for approx. 35 days and will continue to be fed by family members for several weeks thereafter.

Laughing Kookaburras that frequent populated areas can often be encouraged to feed from the hand. This is to be discouraged.

Size 18 in/46cm, weight 16oz/450g, life span 12 years in the wild, to 20 years in captivity.

Main sources for this information;
Wikipedia
Australian Birds, Slater
http://houstonzoo.org

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