The female Common Kingfisher is almost identical in appearance to the male.
The difference between the two lies in the colour of the lower mandible. 
In the male, it is black, or in some cases, mostly black. 
In the female, it is orange-red, or in some cases, mostly orange-red.
Young Common Kingfishers have brown legs while adult Common Kingfishers have red-orange legs.

The 4th photo shows a male who has caught a fish and is on his way to feed his young in the nest built in a hole in a riverbank in the garden of friends of mine in Vreeland.
The next day the young fledged, never to return to the nest.

First 3 photos: Eemmeer/Eemnesserpolder, Eemnes, The Netherlands, 5 September 2019
4th photo: Vreeland, The Netherlands, 6 September 2014
5th photo: Lepelaarsplassen, Almere, The Netherlands, 9 March 2016