Danaus plexippus has been found fourteen times, although eleven of these records probably concern adventives. More interesting are three individuals seen respectively on 22nd November 1969 in Rotterdam Harbour, on 14th October 1995 at Maasvlakte, also in Zuid-Holland, and on 16th November 1995 at Haringvlietdam, in the province of Zeeland. These are probably of American origin, and thus, true vagrants.
Wynhoff, I., Groenendijk, D., Swaay, C. van, Bosveld, M., Bos, F.
- Bos, F., M. Bosveld, D. Groenendijk, C. van Swaay & I. Wynhoff 2006. De dagvlinders van Nederland, verspreiding en bescherming. Nederlandse Fauna 7. De Vlinderstichting, Wageningen en Nationaal Natuurhistorisch Museum Naturalis, European Invertebrate Survey, Nederland.