This photo by Antoine van der Heijden shows a vagrant emperor dragonfly couple; the male on the left, the female on the right.
This is a species from Africa and the Middle East.
Rarely, it flies to western Europe. It was seen for the first time in the Netherlands in 1995. This summer, there are more of them than usually.
Dutch Vroege Vogels radio this morning also reported on other dragonfly species which used to live south of the Netherlands, but which are becoming more common now: like the lesser emperor and the red-veined darter.
Probably, climate change brings these southern species to the Netherlands.