Fig. 2
Examples of hybrid networks for three bird orders: a Anseriformes, b Galliformes and c Charadriiformes. Dots represent species (coloured according to different genera) while edges indicate that hybrid offspring have been observed. Records based on the Serge Dumont Bird Hybrid Database (http://www.bird-hybrids.com, Additional file 1). Drawings used with permission of Handbook of Birds of the World (del Hoyo et al. 2018)