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
Yellow-chinned spinetail The tubular entrance tunnel rises almost vertically from the base to the top of the nest. The normal clutch is three, sometimes four, greenish white eggs. This spinetail is parasitised by the striped cuckoo ("Tapera naevia"), which lays one or two eggs in the nest, but it is not known how the cuckoo enters the nest or whether it or its offspring eject the host's young. This widely ranging bird is not considered threatened by the IUCN. Yellow-chinned spinetail The yellow-chinned spinetail ("Certhiaxis cinnamomeus") is a passerine bird found in the tropical New World from Trinidad and Colombia south to