The term 'Australasian Bird' can be summarized by the crossword solution 'Koel', which is a four-letter word. The Koel is a species of cuckoo found in Australia, New Zealand, and other parts of the Australasian region. It is a medium-sized bird with a long tail and a distinctive call. The Koel is a brood parasite, meaning it lays its eggs in the nests of other birds, leaving them to raise its young.