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BTO Blueline
SONG THRUSH
Turdus philomelos
Conservation listings

Europe: SPEC category 4, secure
UK: Red (>50% population decline)

Long-term trend
UK, England: rapid decline
Status summary
The CBC shows a rapid decline in Song Thrush abundance that began in the mid 1970s. The second half of this decline can also be seen in the CES index. CES productivity showed an initial decrease, followed by stability, and NRS data indicate that breeding performance has improved during this period. Changes in survival of juveniles in their first year of life probably drove the decline (Thomson et al. 1997, Siriwardena et al. 1998a). Recent CBC/BBS data suggest that the decline has at least levelled off, and may now be reversing. Decreasing Song Thrush abundance has been linked to agricultural intensification (Fuller et al. 1995), but woodland-specific factors such as drainage and the depletion of the shrub layer may also be implicated (Vanhinsbergh et al. 2003).
 
CBC/BBS UK graph
 
Table of population changes for Song Thrush
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC/BBS UK 33 1967-2000 485 -55 -62 -45 >50  
  25 1975-2000 578 -47 -54 -41 >25  
  10 1990-2000 1062 4 -5 13    
  5 1995-2000 1619 12 8 16    
CBC/BBS England 33 1967-2000 393 -57 -64 -50 >50  
  25 1975-2000 465 -52 -59 -43 >50  
  10 1990-2000 840 1 -7 9    
  5 1995-2000 1271 8 5 12    
CES adults 17 1984-2001 79 -31 . . [>25*]  
  10 1991-2001 91 -17 . .    
  5 1996-2001 90 -6 . .    
CES juveniles 17 1984-2001 63 -52 . . [>50*]  
  10 1991-2001 73 -8 . .    
  5 1996-2001 74 2 . .    
BBS UK 8 1994-2002 1394 13 8 19    
BBS England 8 1994-2002 1082 14 8 20    
BBS Scotland 8 1994-2002 131 8 -10 31    
BBS Wales 8 1994-2002 126 25 7 45    
BBS N.Ireland 8 1994-2002 47 28 -11 84    
BBS acknowledgement
 
CBC/BBS England graph
CES adult abundance graph
CES juvenile abundance graph
BBS UK graph
BBS England graph
BBS Scotland graph
BBS Wales graph
BBS N Ireland graph
 
Table of productivity information for Song Thrush
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 33 1968-2001 175 None        
Brood size 33 1968-2001 194 None        
Daily failure rate (eggs) 20 1981-2001 347 Linear decline 0.0424 nests/day 0.0298 nests/day -0.0126 nests/day  
Daily failure rate (chicks) 20 1981-2001 258 None        
Laying date 33 1968-2001 202 None        
Percentage juveniles (CES) 17 1984-2001 86 Smoothed trend 147 productivity index 101 productivity index -32%[>25]  
Percentage juveniles (CES) 10 1991-2001 100 Smoothed trend 90 productivity index 101 productivity index 11%  
Percentage juveniles (CES) 5 1996-2001 100 Smoothed trend 96 productivity index 101 productivity index 5%  
 
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