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Breeding Bird Survey
Common Birds Census
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Waterways Bird Survey
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SONG THRUSH Turdus philomelos
 
Conservation Listings Long term trend

Table 3/Red
(>=50% Population decline)

Biodiversity Steering Group
Priority Species Group

UK: Rapid decline
Farmland: Rapid decline
Woodland: Moderate decline
 
Status Summary
The CBC shows a rapid decline in Song Thrush abundance that began in the mid-1970s and latter half of the decline can also be seen in the CES index. CES productivity shows no clear temporal trend and breeding performance from the NRS has improved (the change in failure at the egg stage (16 days, comprising 13 days incubation + 3 days laying) was only from 49% in 1981 to 42% in 1998); 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 and BBS trends suggest that the decline has levelled off. The decline 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. 2001).
 
 
Table of population changes for Song Thrush
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC all habitats 30 1968-1998 204 -60 -65 -50 >50  
  25 1973-1998 208 -57 -63 -48 >50  
  10 1988-1998 186 -10 -20 1    
  5 1993-1998 192 -1 -8 7    
CBC farmland 30 1968-1998 86 -71 -78 -65 >50  
  25 1973-1998 83 -69 -75 -63 >50  
  10 1988-1998 76 -20 -31 -9    
  5 1993-1998 75 -6 -15 4    
CBC woodland 30 1968-1998 80 -50 -59 -35 >25  
  25 1973-1998 86 -45 -57 -31 >25  
  10 1988-1998 90 0 -13 19    
  5 1993-1998 95 5 -3 16    
CES adults 14 1984-1998 79 -39 . . [>25*]  
  10 1988-1998 90 -30 . . [>25*]  
  5 1993-1998 95 -21 . .    
CES juveniles 14 1984-1998 63 -54 . . [>50*]  
  10 1988-1998 72 -24 . .    
  5 1993-1998 77 -13 . .    
BBS UK 5 1994-1999 1316 6 0 11    
BBS England 5 1994-1999 1029 1 -4 7    
BBS Scotland 5 1994-1999 128 20 -1 45    
BBS Wales 5 1994-1999 109 12 -6 32    
BBS N.Ireland 5 1994-1999 42 9 -27 63   Small sample
The Breeding Bird Survey is jointly funded by BTO, JNCC and RSPB
 
 
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 30 1968-1998 172 None        
Brood size 30 1968-1998 189 None        
Daily failure rate (eggs) 17 1981-1998 201 Linear decline 0.0417 nests/day 0.033 nests/day -0.0087 nests/day  
Daily failure rate (chicks) 17 1981-1998 149 None        
Laying date 30 1968-1998 198 None        
Percentage juveniles (CES) 14 1984-1998 85 Smoothed trend 132 productivity index 100 productivity index -24%  
Percentage juveniles (CES) 10 1988-1998 97 Smoothed trend 86 productivity index 100 productivity index 17%  
Percentage juveniles (CES) 5 1993-1998 104 Smoothed trend 87 productivity index 100 productivity index 15%  
 

 

   



The report should be cited as: Baillie, S.R., Crick, H.Q.P., Balmer, D.E., Bashford, R.I., Beaven, L.P., Freeman, S.N., Marchant, J.H., Noble, D.G., Raven, M.J., Siriwardena, G.M., Thewlis, R. and Wernham, C.V. (2001) Breeding Birds in the Wider Countryside: their conservation status 2000. BTO Research Report No. 252. BTO, Thetford. (http://www.bto.org/birdtrends)

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