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BTO Blueline
MOORHEN
Gallinula chloropus
Moorhen © G H Higginbotham
 
Conservation listings

Europe: no SPEC category, secure
UK: Green

Long-term trend
UK, England: shallow increase
 
Status summary
While the long-term trend is of shallow increase, much of the population increase took place before 1974, when WBS monitoring began, and may have been a recovery from heavy mortality during the cold winters of the early 1960s. On both CBC/BBS and WBS evidence, there was decrease during the 1970s and 1980s, but this has been followed by a partial recovery. A decline in the number and quality of farmland ponds, and the spread of American mink Mustela vison, which is an important predator especially along watercourses, have been suggested as possible causes of decline. The decline has been associated with significant reductions in breeding performance. Average clutch size has declined and the failure rate of nests over the full 25-day egg period (20 days for incubation and 5 days for laying) has increased, but average brood sizes have improved.
 
WBS UK graph
 
Table of population changes for Moorhen
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC/BBS UK 33 1967-2000 201 20 -7 58    
  25 1975-2000 234 -9 -26 11    
  10 1990-2000 406 4 -10 15    
  5 1995-2000 607 7 0 14    
CBC/BBS England 33 1967-2000 182 27 0 61    
  25 1975-2000 213 -3 -22 18    
  10 1990-2000 374 3 -6 20    
  5 1995-2000 557 7 3 14    
WBS waterways 25 1975-2000 76 -13 -33 15    
  10 1990-2000 83 4 -14 22    
  5 1995-2000 78 -3 -12 6    
BBS UK 8 1994-2002 503 22 11 35    
BBS England 8 1994-2002 461 18 6 30    
BBS acknowledgement
 
CBC/BBS UK graph
CBC/BBS England graph
BBS UK graph
BBS England graph
 
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 33 1968-2001 95 Linear decline 6.48 eggs 6.1 eggs -0.38 eggs  
Brood size 33 1968-2001 78 Curvilinear 3.36 chicks 4.49 chicks 1.13 chicks  
Daily failure rate (eggs) 33 1968-2001 111 Curvilinear 0.0143 nests/day 0.021 nests/day 0.0067 nests/day  
Daily failure rate (chicks) 33 1968-2001 32 None        
Laying date 33 1968-2001 72 None        
 
Clutch size graph
Brood size graph
Egg nest failure graph

 

 

Insufficient data on nestling failure
available for this species

Laying date graph

 

 

Insufficient data on 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