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BTO Blueline
BLUE TIT
Cyanistes caeruleus
 Blue Tit © George H Higginbotham
 

• Population
  changes

• Productivity
  trends

• Additional
  information
Conservation listings
Europe: no SPEC category (concentrated in Europe, conservation status favourable)
UK: green
Long-term trend
UK, England: shallow increase
UK population size
3,535,000 territories in 2000 (1988–91 Atlas estimate updated using CBC/BBS trend: BiE04, APEP06)
Status summary
Blue Tit populations have increased in abundance, in parallel with those of Great Tits, with brief pauses in the long-term upward trend. The recent years of the CBC/BBS index show fluctuations but no clear trend. Food provision by humans during winter and availability of nest boxes, which may reduce egg and nestling predation, have both increased and may have contributed to the rise in population. Decreasing clutch and brood sizes, and a substantial decline in the proportion of young birds in early autumn, have accompanied the population increase.
 

Population changes
CBC/BBS UK graph
 
Table of population changes for Blue Tit

Source Period
(yrs)		 Years Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
CBC/BBS England 36 1967-2003 528 35 19 50    
  25 1978-2003 685 15 6 25    
  10 1993-2003 1422 9 5 12    
  5 1998-2003 1656 2 -1 4    
CBC/BBS UK 36 1967-2003 636 37 25 54    
  25 1978-2003 830 19 9 30    
  10 1993-2003 1735 13 9 17    
  5 1998-2003 2051 4 2 7    
CES adults 19 1984-2003 94 4 -11 22    
  10 1993-2003 108 13 4 24    
  5 1998-2003 105 -7 -15 2    
CES juveniles 19 1984-2003 93 -24 -40 -1    
  10 1993-2003 108 -10 -22 1    
  5 1998-2003 105 8 -4 19    
BBS UK 10 1994-2004 1772 17 13 22    
BBS England 10 1994-2004 1437 10 6 15    
BBS Scotland 10 1994-2004 123 46 23 72    
BBS Wales 10 1994-2004 148 30 14 47    
BBS N.Ireland 10 1994-2004 57 80 32 146    

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
 

Productivity trends
Table of productivity changes for Blue Tit

Variable Period
(yrs)		 Years Mean
annual
sample		 Trend Modelled
in first year		 Modelled
in 2003		 Change Comment
Clutch size 35 1968-2003 83 Curvilinear 9.14 eggs 8.39 eggs -8.2%  
Brood size 35 1968-2003 135 Curvilinear 8.04 chicks 7.17 chicks -10.8%  
Daily failure rate (eggs) 35 1968-2003 134 Linear decline 0.5% nests/day 0.22% nests/day -56%  
Daily failure rate (chicks) 35 1968-2003 115 None        
Laying date 35 1968-2003 116 Curvilinear May 1 Apr 24 -7 days  
Juvenile to Adult ratio (CES) 19 1984-2003 98 Smoothed trend 152 Index value 103 Index value -34% >25  
Juvenile to Adult ratio (CES) 10 1993-2003 112 Smoothed trend 130 Index value 103 Index value -23%  
Juvenile to Adult ratio (CES) 5 1998-2003 110 Smoothed trend 90 Index value 103 Index value 11%  

 
Clutch size graph
Brood size graph
Egg nest failure graph
Chick nest failure graph
Laying date graph
CES productivity graph
 

Additional information
BTO blue divider
BirdWeb logo, click to go to BirdWeb

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This report should be cited as:
Baillie, S.R., Marchant, J.H., Crick, H.Q.P., Noble, D.G., Balmer, D.E., 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. (2006)
Breeding Birds in the Wider Countryside: their conservation status 2005.
BTO Research Report No. 435. BTO, Thetford. (http://www.bto.org/birdtrends)

Pages maintained by Susan Waghorn and Iain Downie: Last updated 2 May, 2006