BTO - Breeding Birds of the Wider Countryside: Moorhen

MOORHEN
Gallinula chloropus

Conservation listings

Europe: no SPEC category (favourable conservation status in Europe, not concentrated in Europe)
UK: green

Long-term trend

UK, England: shallow increase

Distribution maps

Maps and statistics from British and Irish
atlases can be viewed here.

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.

Table of population changes for Moorhen

Source Period
(yrs) Years Plots
(n) Change
(%) Lower
limit Upper
limit Alert Comment

CBC/BBS UK 35 1967-2002 210 31 2 65

25 1977-2002 257 4 -14 26

10 1992-2002 484 16 4 27

5 1997-2002 620 21 14 27

CBC/BBS England 35 1967-2002 191 39 8 74

25 1977-2002 234 10 -9 35

10 1992-2002 446 16 4 32

5 1997-2002 567 22 15 31

WBS waterways 27 1975-2002 75 -13 -34 21

25 1977-2002 75 -15 -34 16

10 1992-2002 81 0 -13 14

5 1997-2002 66 -2 -12 7

BBS UK 9 1994-2003 508 32 19 45

BBS England 9 1994-2003 467 26 14 39

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 34 1968-2002 93 Linear decline 6.51 eggs 6.05 eggs -0.46 eggs

Brood size 34 1968-2002 77 Curvilinear 3.3 chicks 4.43 chicks 1.13 chicks

Daily failure rate (eggs) 34 1968-2002 109 Curvilinear 0.014 nests/day 0.021 nests/day 0.007 nests/day

Daily failure rate (chicks) 34 1968-2002 33 None

Laying date 34 1968-2002 69 None

Insufficient data on nestling failure
available for this species

Insufficient data on CES
available for this species


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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