Fig. 1.5.

The bars refer to relatedness and evolution of specific families. The light grey coloured tree contains the owls, while the black tree indicates the position of frogmouths and nightjars. The grey box indicates the substantial numbers of different avian groups that separate owls from frogmouths but the families themselves are not relevant here. The vertical columns indicate suggestions on where avian families belong, showing considerable disagreement between three different taxonomists. The abbreviations for orders are: APO (Apodiformes), BUC (Bucerotiformes), CAP (Caprimulgiformes), CIC (Ciconiiformes), COL (Coliiformes), COR (Coraciiformes), FAL (Falconiformes), GLB (Galbuliformes), GRU (Gruiformes), PAS (Passeriformes), PIC (Piciformes), PSI (Psittaciformes), STR (Strigiformes), TRC (Trochiliformes), TRO (Trogoniformes), and UPU (Upupiformes). The figure is a pictorial summary simplified and adapted from Hackett et al.13 The three taxonomies merely serve as example here (there are many more proposals) and are far more extensively discussed by Hackett et al.13