Neoaves

Neoaves is a clade that consists of all modern birds (Neornithes or Aves) with the exception of Paleognathae (ratites and kin) and Galloanserae (ducks, chickens and kin). The early diversification of the various neoavian groups occurred very rapidly around the Cretaceous–Paleogene extinction event, and attempts to resolve their relationships with each other have resulted initially in much controversy.

Phylogeny
One hypothesis for the phylogeny of modern birds was presented by Prum, R.O. et al. (2015)

The following cladogram illustrates the proposed relationships, with some taxon names following Yury, T. et al. (2013) and Kimball et al. 2013.

Cladogram of modern birds relationships based on Jarvis, E.D. et al. (2014) with some clade names after Yury, T. et al. (2013).