Jays occur from northwest Africa and Iberia right across Eurasia to Japan and from Iran and the Himalayas to China and southeast Asia. They breed throughout Europe except in Iceland, the far north of Fenno-Scandia and Russia. They are mainly sedentary but are occasionally eruptive, for example in response to failures in the acorn crop.
    In Britain they are absent from much of northern Scotland, the northern and western isles, upland areas in southern Scotland and the Pennines but they are otherwise wide-spread. Bird Atlas 2007-2011 revealed a northwards expansion since the 1968-72 Breeding Atlas into previously unoccupied areas in northern England and southern Scotland. There was also an area in the Fens from which they were absent but which they have now colonised.
    In the 19th century Jays were much persecuted by game-keepers and also shot for their blue wing-coverts (used to make fishing flies). In the 20th century, reduced persecution during the two world wars and increased habitats due to conifer afforestation led to their becoming increasingly common. In Wiltshire they are common in all areas with suitable habitat and appear to be increasing : Birds of Wiltshire recorded them in 435 tetrads in summer, with confirmed or probable breeding in 107 of them; WTA2 recorded them in 480 tetrads with confirmed or probable breeding in 139.

The following references are used throughout these species accounts, in the abbreviated form given in quotation marks:
1968-72 Breeding Atlas” – Sharrack, J.T.R. 1976:  The Atlas of Breeding Birds in Britain and Ireland. T. & A. Poyser
1981-84 Winter Atlas” – Lack, P.C. 1986:  The Atlas of Wintering Birds in Britain and Ireland. T. & A. Poyser
1988-91 Breeding Atlas” – Gibbons, D.W., Reid, J.B. & Chapman, R.A. 1993: The New Atlas of Breeding Birds in Britain and Ireland 1988-91. T. & A. Poyser
“Birds of Wiltshire” – Ferguson-Lees, I.J. et al. 2007 : Birds of Wiltshire, published by the tetrad atlas group of the Wiltshire Ornithological Society after mapping fieldwork 1995-2000. Wiltshire Ornithological Society.
Bird Atlas 2007-2011” – Balmer, D.E., Gillings, S., Caffrey, B.J., Swann, R.L., Downie, I.S. and Fuller, R.J. 2013: Bird Atlas 2007-2011: the Breeding and Wintering Birds of Britain and Ireland
WTA2” – ("Wiltshire Tetrad Atlas 2 ") the present electronic publication, bringing together the Wiltshire data from “Birds of Wiltshire” and “Bird Atlas 2007-11”, together with data from further fieldwork carried out in 2011 and 2012.
"Hobby" - the annual bird report of the Wiltshire Ornithological Society.