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
.
MOORHEN Gallinula chloropus
 
Conservation Listings Long term trend

Unlisted/Green
Biodiversity Steering Group: Unlisted

UK: Fluctuating with no long-term trend
Lowland farmland: Moderate decline
 
Status Summary
Moorhen numbers on linear waterways have fluctuated and show no long-term trend. However, numbers on farmland CBC plots have shown a moderate decline since 1972, which may indicate a decline in number and quantity of farm ponds and other standing waterbodies. The decline has been associated with significant reductions in breeding performance. Average clutch size has declined by nearly half an egg and the failure rate of nests over the full 25-day egg period (20 days for incubation and 5 days for laying) has increased from 31% to 40%.
 
 
Table of population changes for Moorhen
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC all habitats 30 1968-1998 100 -5 -28 17    
  25 1973-1998 101 -22 -37 -5    
  10 1988-1998 90 -7 -19 6    
  5 1993-1998 94 -8 -16 0    
CBC farmland 30 1968-1998 57 -32 -48 -11 >25  
  25 1973-1998 55 -45 -54 -31 >25  
  10 1988-1998 52 -3 -12 7    
  5 1993-1998 53 -5 -14 7    
WBS waterways 23 1975-1998 79 -11 -33 16    
  10 1988-1998 90 12 -9 34    
  5 1993-1998 96 0 -8 8    
BBS UK 5 1994-1999 478 18 6 30    
BBS England 5 1994-1999 438 17 5 29    
The Breeding Bird Survey is jointly funded by BTO, JNCC and RSPB
 
 
Table of productivity information for Moorhen
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 30 1968-1998 98 Linear decline 6.52 eggs 6.08 eggs -0.44 eggs  
Brood size 30 1968-1998 80 Curvilinear 3.51 chicks 4.43 chicks 0.92 chicks  
Daily failure rate (eggs) 30 1968-1998 113 Curvilinear 0.0146 nests/day 0.0199 nests/day 0.0053 nests/day  
Laying date 30 1968-1998 74 None        
 
Insufficient data on nestling failure
available for this species
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: 18 April, 2001

Page created by Susan Waghorn