Wider Countryside Report Header
BTO Blueline
Main WCR menu image Site navigation menu item Results overview menu item Other info menu item BTO website menu item
BTO Blueline
JACKDAW
Corvus monedula
Jackday © Tommy Holden
 
Conservation listings
Europe: no SPEC category (concentrated in Europe, conservation status favourable)
UK: green
Long-term trend
UK, England: moderate increase
Distribution maps
Maps and statistics from British and Irish
atlases can be viewed here.
Status summary
Jackdaws have increased in abundance since the 1960s (Gregory & Marchant 1996), and more recent BBS data suggest the increase is continuing, at least in England. 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 35 1967-2002 344 73 21 154    
  25 1977-2002 460 82 26 146    
  10 1992-2002 1023 28 19 41    
  5 1997-2002 1399 8 4 14    
CBC/BBS England 35 1967-2002 274 63 13 173    
  25 1977-2002 365 66 12 140    
  10 1992-2002 812 31 17 42    
  5 1997-2002 1101 12 6 16    
BBS UK 9 1994-2003 1203 20 13 27    
BBS England 9 1994-2003 947 30 22 39    
BBS Scotland 9 1994-2003 90 4 -17 31    
BBS Wales 9 1994-2003 110 3 -15 26    
BBS N.Ireland 9 1994-2003 52 4 -24 43    
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 34 1968-2002 39 None        
Brood size 34 1968-2002 78 Curvilinear 2.6 chicks 2.49 chicks -0.11 chicks  
Daily failure rate (eggs) 34 1968-2002 48 Linear decline 0.0075 nests/day 0.0024 nests/day -0.0051 nests/day  
Daily failure rate (chicks) 34 1968-2002 47 Linear decline 0.0128 nests/day 0.0027 nests/day -0.0101 nests/day  
Laying date 34 1968-2002 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
BTO blue divider
BirdWeb logo, click to go to BirdWeb

BTO Home | JNCC Home
BTO, The Nunnery, Thetford, Norfolk IP24 2PU, UK.
 © British Trust for Ornithology (Registered Charity Number 216652).
Terms and Conditions | Privacy Statement          Email:


This report should be cited as:
Baillie, S.R., Marchant, J.H., Crick, H.Q.P., Noble, D.G., 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. (2005)
Breeding Birds in the Wider Countryside: their conservation status 2004.
BTO Research Report No. 385. BTO, Thetford. (http://www.bto.org/birdtrends)

Pages maintained by Susan Waghorn and Iain Downie: Last updated 18 January, 2006