Map explanation

This map shows where changes occurred in the breeding season distribution of the species in Wiltshire between 1995-2000 and 2007-2012, as revealed by the fieldwork for Birds of Wiltshire (Wiltshire Ornithological Society 2007) and the shared fieldwork for Bird Atlas 2007-2011 (BTO 2013) and for Wiltshire Tetrad Atlas 2007-2012.

Gains and improvements

Status

Nos tetrads


Absent to present

77

8%


Present to breeding

86

9%


Absent to breeding

49

5%


No change

Status

Nos tetrads


Present in both

103

11%


Breeding in both

116

13%


Losses and declines

Status

Nos tetrads


Present to absent

107

12%


Breeding to present

143

16%


Breeding to absent

133

15%


Mistle Thrushes breed from northwest Africa through much of Europe east into Siberia and also into Turkey, patchily eastward through northern Iran to central Asia and the northwest Himalayas. The northern and east European and most of the Asian populations are migratory, wintering in or just beyond the south of the breeding range.
    Mistle Thrushes reached Britain in the late 19th century as part of an outward expansion from their place of origin in the middle-altitude montane forests of continental Europe, arriving first in the north then spreading south to colonise virtually the whole of the country apart from some of the highest parts of the Scottish uplands. In the breeding season they are also absent from the Outer Hebrides and the Scottish Northern Isles, though in winter these islands are occupied by migrants from the mainland. While there have been only minimal changes in distribution since 1970, abundance figures since that date have shown a marked downward trend. BBS surveys revealed a 35% population decline between 1995 and 2010.
    In Wiltshire Mistle Thrushes were already being described as common by the end of the 19th century. In the 20th century the species mirrored the national trend of stability up until the mid 1970s, followed by a down-turn in numbers (though not in range) up to and beyond the end of the century. Birds of Wiltshire recorded them in 688 tetrads with breeding in 392. WTA2 found them in 574 tetrads with breeding in 385.

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: 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.