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BTO Blueline
GARDEN WARBLER
Sylvia borin
Garden Warbler © Tommy Holden
Conservation listings

Europe: SPEC category 4, secure
UK: Green

Long-term trend
UK, England: fluctuating, with no long-term trend
Status summary
Garden Warbler abundance has varied alongside that of other trans-Saharan migrant warblers (Siriwardena et al. 1998b), probably reflecting the influence of the environment on the wintering grounds. Despite large short-term fluctuations in abundance, the CBC/BBS and CES both suggest long-term population stability. Productivity, as measured by the CES, has declined since 1983.
 
CBC/BBS UK graph
 
Table of population changes for Garden Warbler
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC/BBS UK 33 1967-2000 162 -9 -41 40    
  25 1975-2000 191 54 11 122    
  10 1990-2000 331 -5 -16 6    
  5 1995-2000 489 -3 -11 6    
CBC/BBS England 33 1967-2000 139 -8 -41 42    
  25 1975-2000 164 48 7 109    
  10 1990-2000 278 -5 -17 8    
  5 1995-2000 408 -3 -11 4    
CES adults 17 1984-2001 65 -14 . .    
  10 1991-2001 76 -11 . .    
  5 1996-2001 76 -18 . .    
CES juveniles 17 1984-2001 63 -39 . . [>25*]  
  10 1991-2001 73 -26 . . [>25]  
  5 1996-2001 71 -29 . . [>25]  
BBS UK 8 1994-2002 369 -13 -23 -1    
BBS England 8 1994-2002 302 -11 -22 2    
BBS Wales 8 1994-2002 52 -29 -48 -2 (>25)  
BBS acknowledgement
 
CBC/BBS England graph
CES adult abundance graph
CES juvenile abundance graph
BBS UK graph
BBS England graph
BBS Wales graph
 
Table of productivity information
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 33 1968-2001 17 None       Small sample
Brood size 33 1968-2001 26 None       Small sample
Daily failure rate (eggs) 33 1968-2001 23 None       Small sample
Daily failure rate (chicks) 33 1968-2001 20 Linear increase 0.0097 nests/day 0.025 nests/day 0.0153 nests/day Small sample
Laying date 33 1968-2001 22 None       Small sample
Percentage juveniles (CES) 17 1984-2001 77 Smoothed trend 180 productivity index 101 productivity index -44%[>25]  
Percentage juveniles (CES) 10 1991-2001 89 Smoothed trend 140 productivity index 101 productivity index -28%[>25]  
Percentage juveniles (CES) 5 1996-2001 87 Smoothed trend 131 productivity index 101 productivity index -23%  
 
Clutch size graph
Brood size graph
Egg nest failure graph
Chick nest failure graph
Laying date graph
CES productivity graph
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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