The British Trust for Ornithology
CHIFFCHAFF
Phylloscopus collybita
Chiffchaff © Tommy Holden
Conservation listings

Unlisted/Green
Biodiversity Steering Group Conservation Concern List
Long-term trend
UK: Fluctuating with no long-term trend
Status summary
Chiffchaff abundance crashed in the late 1960s/early 1970s in common with that of other trans-Saharan warblers (Siriwardena et al. 1998). After remaining stable for a decade, the population recovered strongly. This recovery is evident from both CBC and CES data. Climate change may partially explain the trend towards earlier laying (Crick & Sparks 1999). However, over-winter survival may be the critical factor responsible for changes in abundance, as it is for Whitethroat and Sedge Warbler.
 
 
Table of population changes in Chiffchaff
Source Period
(yrs)		 Years Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
CBC all habitats 31 1968-1999 132 16 -4 52    
  25 1974-1999 137 74 45 114    
  10 1989-1999 155 29 16 45    
  5 1994-1999 165 25 16 35    
CBC farmland 31 1968-1999 44 67 23 170    
  25 1974-1999 43 138 74 296    
  10 1989-1999 52 54 26 114    
  5 1994-1999 56 58 36 101    
CBC woodland 31 1968-1999 67 -14 -34 11    
  25 1974-1999 72 31 6 61    
  10 1989-1999 86 10 -1 24    
  5 1994-1999 91 11 4 19    
CES adults 15 1984-1999 63 73 . .    
  10 1989-1999 74 8 . .    
  5 1994-1999 81 8 . .    
CES juveniles 15 1984-1999 75 107 . .    
  10 1989-1999 89 11 . .    
  5 1994-1999 99 27 . .    
BBS UK 6 1994-2000 918 4 -2 12    
BBS England 6 1994-2000 783 5 -1 12    
BBS Scotland 6 1994-2000 20 114 12 306   Small sample
BBS Wales 6 1994-2000 90 -10 -26 10    
BBS N.Ireland 6 1994-2000 20 -28 -61 35   Small sample
The Breeding Bird Survey is jointly funded by BTO, JNCC and RSPB
 
 
Table of productivity information for Chiffchaff
Variable Period
(yrs)		 Years Mean
annual
sample		 Trend Predicted
in first year		 Predicted
in last year		 Change Comment
Clutch size 31 1968-1999 27 None       Small sample
Brood size 31 1968-1999 30 Linear decline 5.12 chicks 4.81 chicks -0.31 chicks Small sample
Daily failure rate (eggs) 31 1968-1999 34 None        
Daily failure rate (chicks) 31 1968-1999 30 None        
Laying date 31 1968-1999 40 Linear decline day 137 day 125 -12 days  
Percentage juveniles (CES) 15 1984-1999 83 Smoothed trend 89 productivity index 100 productivity index 12%  
Percentage juveniles (CES) 10 1989-1999 98 Smoothed trend 109 productivity index 100 productivity index -8%  
Percentage juveniles (CES) 5 1994-1999 107 Smoothed trend 90 productivity index 100 productivity index 11%  
 




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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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