Largest organisms were related to the ostrich. They exceeded in height and . The last of the elephant birds became extinct about 300 years ago. Of almost exactly the same upper proportions as the largest elephant birds was "Dromornis stirtoni" of Australia, part of a 26,000-year-old group called mihirungs of the family Dromornithidae. The largest carnivorous bird was "Brontornis", an extinct flightless bird from South America which reached a weight of and a height of about . The tallest carnivorous bird was "Kelenken", which could reach 3 to 3.2 meters in height and 220 to 250 kilograms. The tallest bird ever was
Crotophaginae to Rio Negro in Argentina, in open habitats. Crotophaginae The Crotophaginae are a small subfamily, within the cuckoo family Cuculidae, of four gregarious bird species occurring in the Americas. They were previously classified as a family Crotophagidae. The subfamily is notable for the development of cooperative breeding where several females lay eggs in a communal nest. It contains the three anis and the guira cuckoo. Among the anis, there is considerable variation in nesting habits. One species, The greater ani "C. major" lays 2 or 3 eggs, while the groove-billed ani "C. sulcirostris" lays seven. However the smooth-billed ani "C.