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BTO Blueline
Phylloscopus sibilatrix
Wood Warbler © Adrian Cawthorne
Conservation listings

Europe: SPEC category 4, (secure)
UK: Amber (25-50% population decline)

Long-term trend
UK: probable decline
Status summary
Wood Warblers, which have a westerly distribution in Britain, were not monitored well before the inception of the BBS. Llittle change was apparent at the few CBC plots on which the species occurred (Crick et al. 1998). The species' range varied little between the two breeding atlas periods (Gibbons et al. 1993), but has subsequently shown further retreat from southeast England. BBS shows a rapid and significant decline since 1994, and accordingly the species has now been moved from the Green to the Amber list. A decrease has been observed in nest failure rates at the egg stage.
CBC/BBS UK graph
Table of population changes for Wood Warbler
Source Period
Years Plots
Alert Comment
BBS UK 8 1994-2002 56 -58 -69 -42 (>50)  
BBS acknowledgement
Table of productivity information
Variable Period
Years Mean
Trend Predicted
in first year
in last year
Change Comment
Clutch size 33 1968-2001 17 None       Small sample
Brood size 33 1968-2001 38 None        
Daily failure rate (eggs) 33 1968-2001 22 Linear decline 0.0199 nests/day 0.0088 nests/day -0.0111 nests/day Small sample
Daily failure rate (chicks) 33 1968-2001 28 None       Small sample
Laying date 33 1968-2001 33 None        
Clutch size graph
Brood size graph
Egg nest failure graph
Chick nest failure graph
Laying date graph
Insufficient data on CES
available for this species
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This report should be cited as:
Crick, H.Q.P., Marchant, J.H., Noble, D.G., Baillie, S.R., Balmer, D.E., Beaven, L.P., Coombes, R.H.,
Downie, I.S., Freeman, S.N., Joys, A.C., Leech, D.I., Raven, M.J., Robinson, R.A. and Thewlis, R.M. (2004)
Breeding Birds in the Wider Countryside: their conservation status 2003.
BTO Research Report No. 353. BTO, Thetford. (http://www.bto.org/birdtrends2003)

Pages maintained by Susan Waghorn and Iain Downie: Last updated 16 February, 2009