Wood Warblers breed throughout much of Eurasia, from Ireland and France to Mongolia, and winter in equatorial Africa.
In Great Britain they are mainly found in upland oak woods in Devon, Wales and western Scotland, with local concentrations also found in suitable lowland wooded areas such as the New Forest. Bird Atlas 2007-2011 recorded a 37% contraction in the breeding season distribution of the species in Great Britain since the 1968-72 Breeding Atlas and a 65% in numbers between 1995 and 2010 as revealed by the annual Breeding Bird Survey.
The first record of a Wood Warbler in Wiltshire dates from 1790 and there were scattered reports of them throughout the 19th century but it was not until the first half of the 20th Century that they started being recorded as “not uncommon” in suitable wooded areas. Their distribution in the county remained roughly the same until the end of the century though actual numbers declined. Birds of Wiltsire recorded them present in 49 tetrads, with breeding confirmed or probable in 20. WTA2 recorded them in 41 tetrads with breeding confirmed or probable in only seven.

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: The Breeding and Wintering Birds of Britain and Ireland. BTO Books. 
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.