VRIES TG DE (1934) Miscellanea o?logica et nidologica, IX. LIMOSA 7 (1): 52-52.

Mallard Anas platyrhynchos Common Kestrel Falco tinnunculus A strange clutch of the wild duck. On March 31 this year, the purple heron colony, in the land of Vollenhove, a clutch of seven eggs from the wild duck, Anas platyrhyncha platyrhyncha found by Dr. AT KATE at the general meeting in Holly is demonstrated and very favorable for my collection was ceded

[free pdf] [dutch summary]