He found estrildids uniform among themselves and distant from Ploceidae (including Viduinae) and Fringillidae.
In addition, 23 skeletons of eight species of Viduinae and 52 skeletons of 22 species of 13 genera of Ploceidae (two genera of Bubalornithinae, five of Passerinae, and six of Ploceinae) were compared.
Osteological data are equivocal as to whether the Viduinae belong in Estrildidae or Ploceidae or in a separate family by themselves.
However, Vidua and Anomalospiza bear about the same weight of osteological distinction from the other subfamilies of Ploceidae as they do from Estrildidae.
Sushkin (1927) listed skeletal differences between the Estrildidae (excluding Viduinae) and Ploceidae (Bubalornitinae, Passerinae, and Ploceinae).