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WREN
Troglodytes troglodytes
Wren © Tommy Holden
 
Conservation listings

Europe: no SPEC category, secure
UK: Green

Long-term trend
England: moderate increase
 
Status summary
Following a rapid increase into the mid 1970s, Wren abundance has fluctuated; BBS results suggest further recent rise in all parts of the UK. Abundance can vary sharply from year to year in this species, influenced by mortality rates that may be very high in severe winters and by the species' high breeding potential (Peach et al. 1995b), although this is largely concealed by smoothing in the CBC/BBS trends. Breeding performance has shown some small improvements in the long term.
 
CBC/BBS England graph
 
Table of population changes for Wren
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC/BBS England 33 1967-2000 472 88 61 115    
  25 1975-2000 567 -2 -13 10    
  10 1990-2000 1064 10 5 15    
  5 1995-2000 1621 14 11 17    
CES adults 17 1984-2001 93 48 . .    
  10 1991-2001 109 11 . .    
  5 1996-2001 112 7 . .    
CES juveniles 17 1984-2001 92 49 . .    
  10 1991-2001 107 7 . .    
  5 1996-2001 110 13 . .    
BBS UK 8 1994-2002 1784 14 10 18    
BBS England 8 1994-2002 1389 7 3 10    
BBS Scotland 8 1994-2002 174 38 19 59    
BBS Wales 8 1994-2002 152 19 8 32    
BBS N.Ireland 8 1994-2002 59 64 27 112    
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 Wren
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 33 1968-2001 99 Linear increase 5.58 eggs 5.86 eggs 0.28 eggs  
Brood size 33 1968-2001 128 Linear increase 3.63 chicks 4.58 chicks 0.95 chicks  
Daily failure rate (eggs) 33 1968-2001 147 None        
Daily failure rate (chicks) 33 1968-2001 102 None        
Laying date 33 1968-2001 90 None        
Percentage juveniles (CES) 17 1984-2001 97 Smoothed trend 99 productivity index 101 productivity index 1%  
Percentage juveniles (CES) 10 1991-2001 113 Smoothed trend 110 productivity index 101 productivity index -9%  
Percentage juveniles (CES) 5 1996-2001 115 Smoothed trend 98 productivity index 101 productivity index 2%  
 
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