Green Woodpeckers are found in Europe north to southern Scandinavia and east to central Russia; outside of Europe their range is restricted to Turkey and the Caucasus to northern Iran. In Britain, they are most numerous in southern England and South Wales, declining in northern England and south Scotland and rare in northern Scotland (and totally absent from Ireland and the Isle of Man).
    Their specialised feeding pattern, mainly on the ground picking up ants and other insects with their tongue, makes them vulnerable to extended periods of cold weather.  In Great Britain this led to sharp falls in numbers after the harsh winters of 1946-47 and 1962-63. Since then numbers have increased steadily: Bird Atlas 2007-2011 recorded them present in 54% of 10km squares in summer and 52% in winter.
    In Wiltshire, WTA2 recorded them present in the breeding season in 575 tetrads, with breeding confirmed or probable in 182, which amounted to a 16% increase overall since Birds of Wiltshire and a 31% increase in the number of tetrads where breeding was confirmed or probable.
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.