Kookaburra larger group known as "kingfishers", kookaburras are not closely associated with water. The genus "Dacelo" was introduced by the English zoologist William Elford Leach in 1815. The type species is the laughing kookaburra. The name "Dacelo" is an anagram of "Alcedo", the Latin word for a kingfisher. A molecular study published in 2017 found that the genus "Dacelo", as currently defined, is paraphyletic. The shovel-billed kookaburra in the monotypic genus "Clytoceyx" sits within "Dacelo". Four species of kookaburra can be found in Australia, New Guinea, and the Aru Islands. Kookaburras are sexually dimorphic. This is noticeable in the blue-winged and
The Life of Birds possibly show paths this evolution may have taken. One of the biggest birds to have ever existed was the terror bird, which proliferated after dinosaurs vanished and stood up to 2.5 metres tall. By comparison, the ostrich, while not closely related, is the largest and heaviest living bird. It was probably the evasion of predators that drove most birds into the air, so their flightless cousins evolved because they had few enemies. Accordingly, such species are more likely to be found on islands, and Attenborough visits New Zealand to observe its great variety, most especially the kiwi. Also depicted is