List of bird families by number of genera and species

{| class="sortable" border="1" !Family number !! Order !! Family !! Number of genera !! Number of species !! Notes
 * 1 || Struthioniformes || Struthionidae || 1 || 2 || Sometimes the two ostriches species are considered monotypic.
 * 2 || Rheiformes || Rheidae || 1 || 2 ||
 * 3 || Apterygiformes || Apterygidae || 1 || 5 ||
 * 2 || Rheiformes || Rheidae || 1 || 2 ||
 * 3 || Apterygiformes || Apterygidae || 1 || 5 ||
 * 3 || Apterygiformes || Apterygidae || 1 || 5 ||