Largest organisms is frequently poorly documented and many are subject to conjecture and estimation. The largest living bird, a member of the Struthioniformes, is the common ostrich ("Struthio camelus"), from the plains of Africa and Arabia. A large male ostrich can reach a height of and weigh over . A mass of has been cited for the common ostrich but no wild ostriches of this weight have been verified. Eggs laid by the ostrich can weigh and are the largest eggs in the world today. The largest bird in the fossil record may be the extinct elephant birds ("Aepyornis") of Madagascar, which
Ruby-crowned kinglet is migratory, and its range extends from northwest Canada and Alaska south to Mexico. Its breeding habitat is spruce-fir forests in the northern and mountainous regions of the United States and Canada. The ruby-crowned kinglet builds a cup-shaped nest, which may be pensile or placed on a tree branch and is often hidden. It lays up to 12 eggs, and has the largest clutch of any North American passerine for its size. It is mainly insectivorous, but also eats fruits and seeds. The ruby-crowned kinglet is a very small bird, being long, having a wingspan of , and weighing .