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BTO Blueline
JACKDAW
Corvus monedula
Jackday © Tommy Holden
Conservation listings

Europe: SPEC category 4, (secure)
UK: Green

Long-term trend
UK, England: moderate increase
Status summary
Jackdaws have increased in abundance since the 1960s (Gregory & Marchant 1996), and more recent BBS data suggest the increase is continuing. As with Magpie, Rook and Carrion Crow, the increase has been associated with improvements in breeding performance and probably reflects the species' generalist feeding habits, which allow it to exploit diverse and ephemeral food resources. A minor increase long-term in average brood size has been compounded by substantial declines in nest failure rates during the egg stage (21 days, comprising 17 days incubation + 4 days laying) and chick stage (30 days). Overall, from egg-laying to fledging, the proportion of nests that fail has fallen by about two-thirds. Typically in this species, the younger chicks of a brood perish quickly if food becomes limited. Larger brood sizes and increases in fledging success are therefore likely to be due to improved parental provisioning success (Henderson & Hart 1993). Brood sizes were unusually small in 2001 and 2002, however.
 
CBC/BBS UK graph
 
Table of population changes for Jackdaw
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC/BBS UK 33 1967-2000 316 71 11 167    
  25 1975-2000 397 80 23 153    
  10 1990-2000 829 29 16 46    
  5 1995-2000 1308 15 7 22    
CBC/BBS England 33 1967-2000 253 58 1 163    
  25 1975-2000 316 63 12 147    
  10 1990-2000 660 29 13 49    
  5 1995-2000 1039 17 10 25    
BBS UK 8 1994-2002 1178 12 5 19    
BBS England 8 1994-2002 932 18 10 26    
BBS Scotland 8 1994-2002 88 15 -9 46    
BBS Wales 8 1994-2002 107 3 -16 26    
BBS N.Ireland 8 1994-2002 46 -11 -36 26    
BBS acknowledgement
 
CBC/BBS England graph
BBS UK graph
BBS England graph
BBS Scotland graph
BBS Wales graph
BBS N Ireland graph
 
Table of productivity information for Jackdaw
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 33 1968-2001 40 None        
Brood size 33 1968-2001 78 Curvilinear 2.62 chicks 2.66 chicks 0.04 chicks  
Daily failure rate (eggs) 33 1968-2001 49 Linear decline 0.0075 nests/day 0.0026 nests/day -0.0049 nests/day  
Daily failure rate (chicks) 33 1968-2001 47 Linear decline 0.0126 nests/day 0.0029 nests/day -0.0097 nests/day  
Laying date 33 1968-2001 20 Curvilinear day 113 day 110 -3 days Small sample
 
Clutch size graph
Brood size graph
Egg nest failure graph
Chick nest failure graph
Laying date graph
Insufficient data for 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