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BLACKCAP
Sylvia atricapilla
Blackcap © Colin Varndell
 
Conservation listings

Europe: SPEC category 4, secure
UK: Green

Long-term trend
UK, England: 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/BBS and the CES indices, although the causes remain unknown. There have been no clear accompanying trends in productivity. The trend towards earlier laying may be a response to recent climate change (Crick & Sparks 1999).
 
CBC/BBS UK graph
 
Table of population changes for Blackcap
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC/BBS UK 33 1967-2000 366 125 88 185    
  25 1975-2000 445 131 105 173    
  10 1990-2000 831 58 49 65    
  5 1995-2000 1262 40 36 45    
CBC/BBS England 33 1967-2000 327 119 78 173    
  25 1975-2000 396 127 94 168    
  10 1990-2000 734 58 50 67    
  5 1995-2000 1109 37 33 42    
CES adults 17 1984-2001 84 37 . .    
  10 1991-2001 99 32 . .    
  5 1996-2001 102 13 . .    
CES juveniles 17 1984-2001 85 34 . .    
  10 1991-2001 101 32 . .    
  5 1996-2001 104 15 . .    
BBS UK 8 1994-2002 1046 46 38 55    
BBS England 8 1994-2002 917 37 29 46    
BBS Wales 8 1994-2002 87 64 31 105    
BBS acknowledgement
 
CBC/BBS England graph
CES adult abundance graph
CES juvenile abundance graph
BBS UK 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 36 None        
Brood size 33 1968-2001 42 None        
Daily failure rate (eggs) 33 1968-2001 46 None        
Daily failure rate (eggs) 33 1968-2001 46 None        
Daily failure rate (chicks) 33 1968-2001 36 None        
Daily failure rate (chicks) 33 1968-2001 36 None        
Laying date 33 1968-2001 37 Curvilinear day 139 day 129 -10 days  
Percentage juveniles (CES) 17 1984-2001 92 Smoothed trend 107 productivity index 101 productivity index -6%  
Percentage juveniles (CES) 10 1991-2001 108 Smoothed trend 106 productivity index 101 productivity index -6%  
Percentage juveniles (CES) 5 1996-2001 111 Smoothed trend 101 productivity index 101 productivity index -1%  
 
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