Nightjars breed in northwest Africa and throughout much of Europe from the Mediterranean to Fenno-Scandia, across western and central Asia to northern China and southward to Turkey, Iran and northwest Himalayas. All populations are migratory, wintering in sub-Saharan Africa. Numbers and range of the European population have decreased since the 1950s.
    In Britain Nightjars breed from southern England to the southwest lowlands of Scotland, with the main concentration in southeast England. Between the 1968-72 Breeding Atlas and the 1988-91 Breeding Atlas the British breeding range contracted by 51%, but then expanded by 18% between 1991 and Bird Atlas 2007-2011, with the actual numbers within the range more than doubling.
    In Wiltshire, Nightjars have been recorded breeding in small numbers ever since records began. Birds of Wiltshire recorded them present in 16 tetrads with breeding confirmed or probable in eight of them; WTA2 recorded them in 12 tetrads with breeding in six. Since 2012 the number of sites where they were recorded breeding have varied from three in 2013 and nine in 2014 to four in 2015 - though it was suspected that the differences were as much the result of variation in observer effort as actual changes in the number of birds (Hobby).

References
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.