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GARDEN WARBLER Sylvia borin
 
Conservation Listings Long term trend

Unlisted/Green
Biodiversity Steering Group
Conservation Concern List

 UK: Fluctuating with no long-term trend
 
Status Summary
Garden Warbler abundance has varied in parallel, to some extent, with that of other sub-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, CES and BBS all suggest long-term stability. Productivity measured by the CES shows a recent decline.
 
 
Table of population changes for Garden Warbler
Source Period
(yrs)		 Years Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
CBC all habitats 30 1968-1998 85 9 -28 81    
  25 1973-1998 87 49 3 130    
  10 1988-1998 93 -2 -17 12    
  5 1993-1998 99 13 2 25    
CBC farmland 30 1968-1998 27 -8 . .    
  25 1973-1998 26 48 . .    
  10 1988-1998 32 -7 . .    
  5 1993-1998 35 18 . .    
CBC woodland 30 1968-1998 44 -4 -41 69    
  25 1973-1998 47 32 -8 125    
  10 1988-1998 50 -10 -28 9    
  5 1993-1998 53 6 -9 20    
CES adults 14 1984-1998 66 1 . .    
  10 1988-1998 76 3 . .    
  5 1993-1998 82 5 . .    
CES juveniles 14 1984-1998 64 -24 . .    
  10 1988-1998 74 -2 . .    
  5 1993-1998 81 -15 . .    
BBS UK 5 1994-1999 364 13 0 28    
BBS England 5 1994-1999 298 9 -5 25    
BBS Wales 5 1994-1999 49 -8 -32 25   Small sample
The Breeding Bird Survey is jointly funded by BTO, JNCC and RSPB
 
 
Table of productivity information
Variable Period
(yrs)		 Years Mean
annual
sample		 Trend Predicted
in first year		 Predicted
in last year		 Change Comment
Clutch size 30 1968-1998 17 None       Small sample
Brood size 30 1968-1998 26 None       Small sample
Daily failure rate (eggs) 30 1968-1998 23 None       Small sample
Daily failure rate (chicks) 30 1968-1998 20 None       Small sample
Laying date 30 1968-1998 22 None       Small sample
Percentage juveniles (CES) 14 1984-1998 78 Smoothed trend 158 productivity index 100 productivity index -37%[>25]  
Percentage juveniles (CES) 10 1988-1998 89 Smoothed trend 118 productivity index 100 productivity index -15%  
Percentage juveniles (CES) 5 1993-1998 96 Smoothed trend 134 productivity index 100 productivity index -25%[>25]  
 
   




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