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
Des Murs's wiretail to determine how wiretails find a mate. As is typical for south temperate insectivorous birds, during the breeding season of October to February Des Murs's wiretail lays a clutch of two to four eggs, but for the bird's mass these are about the largest eggs of any passerine bird. At long and wide, they weigh twice as much as expected for a 10 gram passerine and a clutch of four weighs more than the adult female - a feat equalled only by much more fecund kinglets. Little is known about incubation, fledging periods, or postfledging parental care due to the