Diurnal birds of prey traditionally belong to the order Falconiformes:
Nocturnal birds of prey - the owls - are classified separately, considered to be members of two extant families of the order Strigiformes:
The New World vultures are usually also regarded as birds of prey, although they may not be closely related to the other groups.
The observation that otherwise unrelated bird groups may perform similar ecological roles and bear striking morphological similarities to one another is explained largely by the idea of convergent evolution.
