The British Trust for Ornithology
BLACKCAP
Sylvia atricapilla
Blackcap © Colin Varndell
 
Conservation listings

Unlisted/Green
Biodiversity Steering Group Conservation Concern List

Long-term trend
UK: Rapid increase
 
Status summary
Blackcap abundance has increased consistently since the late 1970s, a trend common to all habitats and evident from both the CBC and the CES indices. The last seven years' BBS results also show a trend towards increasing abundance, although the causal factors remain unknown. There have been no clear accompanying trends in productivity. The trend towards earlier laying can be explained by recent climate change (Crick & Sparks 1999).
 
 
Table of population changes for Blackcap
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC all habitats 31 1968-1999 156 127 91 170    
  25 1974-1999 166 124 95 153    
  10 1989-1999 177 57 49 68    
  5 1994-1999 184 46 39 54    
CBC farmland 31 1968-1999 57 192 124 284    
  25 1974-1999 59 153 101 214    
  10 1989-1999 68 85 62 104    
  5 1994-1999 70 74 58 89    
CBC woodland 31 1968-1999 72 68 31 121    
  25 1974-1999 79 84 58 116    
  10 1989-1999 88 44 35 56    
  5 1994-1999 93 36 29 45    
CES adults 15 1984-1999 85 40 . .    
  10 1989-1999 99 30 . .    
  5 1994-1999 106 21 . .    
CES juveniles 15 1984-1999 86 34 . .    
  10 1989-1999 100 42 . .    
  5 1994-1999 108 18 . .    
BBS UK 6 1994-2000 1026 49 41 59    
BBS England 6 1994-2000 902 44 36 53    
BBS Scotland 6 1994-2000 27 61 1 156   Small sample
BBS Wales 6 1994-2000 83 66 32 109    
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 31 1968-1999 35 None        
Brood size 31 1968-1999 42 None        
Daily failure rate (eggs) 31 1968-1999 46 None        
Daily failure rate (chicks) 31 1968-1999 35 None        
Laying date 31 1968-1999 37 Curvilinear day 139 day 132 -7 days  
Percentage juveniles (CES) 15 1984-1999 93 Smoothed trend 108 productivity index 100 productivity index -8%  
Percentage juveniles (CES) 10 1989-1999 108 Smoothed trend 100 productivity index 100 productivity index 0%  
Percentage juveniles (CES) 5 1994-1999 115 Smoothed trend 110 productivity index 100 productivity index -9%  
 




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This report should be cited as:
Baillie, S.R., Crick, H.Q.P., Balmer, D.E., Beaven, L.P., Downie, I.S., Freeman, S.N., Leech, D.I., Marchant, J.H.,
Noble, D.G., Raven, M.J., Simpkin, A.P., Thewlis, R.M. and Wernham, C.V.
(2002) Breeding Birds in the Wider
Countryside: their conservation status 2001. BTO Research Report No. 278. BTO, Thetford. (http://www.bto.org/birdtrends)

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