Appendix Figure 1. Distribution in the eastern hemisphere of the 6 wild duck species used in this study. Yellow, summer (breeding) range; blue: winter range; green, permanent range. (Sources: del Hoyo J, Elliot A, Sargatal J, editors. Handbook of the birds of the world. Volume 1: Ostrich to ducks. Barcelona: Lynx Edicions, 1992; Mullarney K, Svensson L, Zetterström D, Grant PJ. ANWB bird guide of Europe [in Dutch]. Baarn, the Netherlands: Tirion Uitgevers, 2000.)
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