The Northern Wheatear is a bird of open stony country and is mainly found on the ground or on top of a rock. 
The plumage of both female and male look rather different in summer and winter.

During the breeding season, the male is blue-grey above with black wings, and white below with an orange flush to the breast.
Outside the breeding season, the male has a buffy-brown crown and back (instead of blue-grey), yellowish-buff underparts and golden edging to the wing feathers (instead of black).

The breeding female is similar to the breeding male, but with pale brownish-grey upperparts, grey-brown wings and duller facial patterns.
Outside the breeding season, the female is generally buff-brown above (instead of grey) with buff and white edging to the wing feathers (instead of brown). 

Outside the breeding season, the male can be distinguished from the female by the black wings with narrow light edges (instead of brown) and a darker eye mask.
Juvenile Northern Wheatears are similar in appearance to the adult non-breeding female.

1st photo: A male. Diependal Nature Reserve, Oranje, The Netherlands, 15 April 2021
2nd photo: A female. Eemnesserpolder, Eemnes, The Netherlands, 5 September 2019
3rd photo: A male. Bargerveen Nature Reserve, Emmen, The Netherlands, 15 May 2018
4th & 5th photo: A female. Terschelling, The Netherlands, 14 October 2006