By Jimfbleak - Own work based on Commons file File:Blank map of Europe (polar stereographic projection) cropped.svg. Map data from Snow, David; Perrins, Christopher M (editors) (1998) The Birds of the Western Palearctic concise edition (2 volumes), Oxford: Oxford: Oxford University Press, pp. 1,346–1,348 ISBN: 019854099X 0. , Mullarney, Killian; Svensson, Lars; Zetterstrom, Dan; Grant, Peter (1999) Collins Bird Guide, London: Collins, p. 336 ISBN: 000219728-6. and Baker, Kevin (1997) Warblers of Europe, Asia and North Africa (Helm Identification Guides), London: Helm, pp. 116 ISBN: 0713639717., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11871148