Inter-specific parasitism in duck species in Central Europe may be an accidental consequence of conspecific breeding parasitism. Analysis of 1,237 nest records for five duck species in South Bohemia from 1999–2008 found that parasitism, where a bird lays its eggs in the nest of another species, had occurred in 6.6% of nests.
Three Red-crested Pochard Netta rufina clutches were all parasitised and Red-crested Pochard most often laid parasitic eggs in the nests of other species