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BTO Blueline
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BTO Blueline

Garrulus glandarius

Conservation listings

Europe: no SPEC category, (secure)
UK: Green

Long-term trend
England: fluctuating, with no long-term trend
Status summary
The UK Jay population remained stable in the species' preferred woodland habitat until the late 1980s, after which the population began to decline. This decrease followed an earlier decline on farmland CBC plots (Gregory & Marchant 1996). Long-term trends are shallowly downward overall, but BBS has recorded substantial increase since 1999. Although sample sizes are small, nest failure rates at the egg stage (21 days, comprising 16 days incubation and 5 days laying) have fallen considerably.
CBC/BBS England graph
Table of population changes for Jay
Source Period
Years Plots
Alert Comment
CBC/BBS England 33 1967-2000 192 -10 -27 14    
  25 1975-2000 228 -13 -28 5    
  10 1990-2000 384 -7 -16 0    
  5 1995-2000 550 -1 -7 6    
BBS UK 8 1994-2002 513 16 5 29    
BBS England 8 1994-2002 447 6 -5 18    
BBS Wales 8 1994-2002 53 1 -29 42    
BBS acknowledgement
BBS UK graph
BBS England graph
BBS Wales graph
Table of productivity information for Jay
Variable Period
Years Mean
Trend Predicted
in first year
in last year
Change Comment
Brood size 33 1968-2001 11 None       Small sample
Daily failure rate (eggs) 33 1968-2001 10 Linear decline 0.0548 nests/day 0.0209 nests/day -0.0339 nests/day Small sample
Insufficient data on clutch size
available for this species
Brood size graph
Egg nest failure graph
Insufficient data on nestling failure
available for this species


Insufficient data on laying date
available for this species



Insufficient data on CES
available for this species


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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