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ROOK Corvus frugilegus
 
Conservation Listings Long term trend

Unlisted/Green
Biodiversity Steering Group: Unlisted

UK: Shallow increase
 
Status Summary
As a colonial species, Rook is not monitored ideally by the CBC, but an index calculated from the available data shows a shallow, long-term increase (Wilson et al. 1998). This is supported by the results of the BTO Rook survey, which indicated an increase of 40% between 1975 and 1996 (Marchant & Gregory 1999). The increase has been associated with general improvements in nesting success and probably reflects the species' adaptability in the face of agricultural change.
 
 
Table of population changes for Rook
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
BBS UK 5 1994-1999 971 8 0 17    
BBS England 5 1994-1999 770 4 -5 13    
BBS Scotland 5 1994-1999 98 -6 -29 23    
BBS Wales 5 1994-1999 58 1 -32 51    
BBS N.Ireland 5 1994-1999 42 107 42 201   Small sample
The Breeding Bird Survey is jointly funded by BTO, JNCC and RSPB
 
 
Table of productivity information for Rook
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 30 1968-1998 12 Linear decline 4.05 eggs 3.32 eggs -0.73 eggs Small sample
Brood size 30 1968-1998 98 Linear increase 2.28 chicks 2.82 chicks 0.54 chicks  
Daily failure rate (eggs) 30 1968-1998 39 Curvilinear 0.0175 nests/day 0.0683 nests/day 0.0508 nests/day  
Daily failure rate (chicks) 30 1968-1998 60 None        
Laying date 30 1968-1998 12 None       Small sample
 
Insufficient data on CES
available for this species
   



The report should be cited as: Baillie, S.R., Crick, H.Q.P., Balmer, D.E., Bashford, R.I., Beaven, L.P., Freeman, S.N., Marchant, J.H., Noble, D.G., Raven, M.J., Siriwardena, G.M., Thewlis, R. and Wernham, C.V. (2001) Breeding Birds in the Wider Countryside: their conservation status 2000. BTO Research Report No. 252. BTO, Thetford. (http://www.bto.org/birdtrends)

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Last updated: Last updated: 9 April, 2001

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