Contents of report
Breeding Bird Survey
Common Birds Census
Constant Effort Sites
Nest Record Scheme
Waterways Bird Survey
Alerts
Summary
What the categories mean
Return to BTO Home Page
.
RAVEN Corvus corax
 
Conservation Listings Long term trend

Unlisted/Green
Biodiversity Steering Group: Unlisted

UK: Unknown
 
Status Summary
The Raven's range has contracted from some areas of northern Britain and gaps in the distribution have been linked to persecution associated with grouse moors (Gibbons et al. 1993, 1995). The BBS indicates current stability in the population, but breeding performance went through a trough in the 1980s in terms of brood size and egg nest losses.
 
 
Table of population changes for Raven
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
BBS UK 5 1994-1999 150 15 -9 44    
BBS England 5 1994-1999 41 22 -19 83   Small sample
BBS Scotland 5 1994-1999 40 19 -26 91   Small sample
BBS Wales 5 1994-1999 56 -8 -35 30    
The Breeding Bird Survey is jointly funded by BTO, JNCC and RSPB
 
 
Table of productivity information for Raven
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 30 1968-1998 12 None       Small sample
Brood size 30 1968-1998 54 None        
Daily failure rate (eggs) 30 1968-1998 19 Curvilinear 0.0024 nests/day 0.0049 nests/day 0.0025 nests/day Small sample
Daily failure rate (chicks) 30 1968-1998 24 None       Small sample
Laying date 30 1968-1998 11 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)

[ Welcome | Contents | Introduction | CBC | WBS | BBS | Heronries | CES | NRS | Alerts ]
[ Summary | Discussion | References | Help | BTO Home Page ]

© British Trust for Ornithology
BTO, The Nunnery, Thetford, Norfolk IP24 2PU
Tel: (+44) (0) 1842 750050 Fax: (+44) (0) 1842 750030 Email:

Last updated: 4 July, 2001

Page created by Susan Waghorn