The British Trust for Ornithology
MUTE SWAN
Cygnus olor
Mute Swan © Mike Weston
Conservation listings

Unlisted/Green
Biodiversity Steering Group Conservation Concern List

Long-term trend
UK: Moderate increase
 
Status summary
Mute Swan populations have increased progressively on both WBS and CBC plots since the mid-1980s, perhaps reflecting the replacement of anglers' lead shot with non-toxic alternatives and warmer winter weather (Gibbons et al. 1993). The trends in breeding performance, although statistically significant, may be due to relatively small, and perhaps unrepresentative, annual samples in the 1990s.
Table of population changes for Mute Swan
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
CBC all habitats 31 1968-1999 20 216 66 487   Unrepresentative? small sample
  25 1974-1999 22 196 87 368   Unrepresentative?
  10 1989-1999 24 88 51 165   Unrepresentative?
  5 1994-1999 27 46 22 85   Unrepresentative?
WBS waterways 24 1975-1999 44 76 12 152    
  10 1989-1999 54 56 27 85    
  5 1994-1999 61 28 13 44    
BBS UK 6 1994-2000 167 20 1 41    
BBS England 6 1994-2000 144 -5 -19 11    
The Breeding Bird Survey is jointly funded by BTO, JNCC and RSPB
Table of productivity information for Mute Swan
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Clutch size 31 1968-1999 19 Linear decline 5.87 eggs 5.09 eggs -0.78 eggs Small sample
Brood size 31 1968-1999 33 None        
Daily failure rate (eggs) 31 1968-1999 26 Curvilinear 0.0081 nests/day 0.0437 nests/day 0.0356 nests/day Small sample
Daily failure rate (chicks) 31 1968-1999 20 None       Small sample
Laying date 31 1968-1999 12 None       Small sample
Insufficient data on CES
available for this species




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This report should be cited as:
Baillie, S.R., Crick, H.Q.P., Balmer, D.E., Beaven, L.P., Downie, I.S., Freeman, S.N., Leech, D.I., Marchant, J.H.,
Noble, D.G., Raven, M.J., Simpkin, A.P., Thewlis, R.M. and Wernham, C.V.
(2002) Breeding Birds in the Wider
Countryside: their conservation status 2001. BTO Research Report No. 278. BTO, Thetford. (http://www.bto.org/birdtrends)

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This page last updated: 21 April, 2008

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