Bird of prey and may be raised to an order of their own, Cathartiiformes. The secretary bird and/or osprey are sometimes listed as subfamilies of Acciptridae: Sagittariinae and Pandioninae, respectively. Australia's letter-winged kite is a member of the family Accipitridae, although it is a nocturnal bird. The nocturnal birds of prey – the owls – are classified separately as members of two extant families of the order Strigiformes: Below is a simplified phylogeny of Telluraves which is the clade where the birds of prey belong to along with passerines and several near-passerine lineages. The orders in bold text are birds of prey orders;
Genomic evolution of birds possibility of genomic expansion in mammals and reptiles. Also, there is no such genomic loss in any vertebrate group as great as that of birds. Its possible that the early chromosomic fragmentation event that lead to the appearance of microchromosomes in birds significantly contributed to this gene loss. These fragmentation events must have taken place in a common ancestor of most birds, since approximately every two out of three species studied have at least 30 pairs of microchromosomes, 2n = 80 being the size of the average karyotype of birds (with the only exception the family Falconidae, which are 2n