The great-spotted woodpecker is the most common and widespread woodpeckers in the Netherlands.
It has black and white plumage, a prominent oval-shaped white patch on each wing and a red patch (trousers) under the tail.
Males have a red patch on the rear of the head which females don't have.
Juveniles can be identified by their red crown which they loose after their first mould (August - September).
Top: A male. In my yard, Hilversum, The Netherlands, 11 May 2005
Left & Middle: A male. Spandersbos, Hilversum, The Netherlands, 4 April 2018
Right & Last: A juvenile. Groote Heide, Heeze, The Netherlands, 2 July 2018