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MUTE SWAN
Cygnus olor
Mute Swan © Mike Weston
 

• Population
  changes

• Productivity
  trends

• Additional
  information
Conservation listings
Europe: no SPEC category (concentrated in Europe, conservation status favourable)
UK: amber (>20% of European breeding population)
Long-term trend
UK, England: rapid increase
UK population size
28,000–30,000 adults in 1990 (Delany et al. 1992: APEP06); 23,900–25,600 pairs in 2000 (updated using CBC/BBS trend: BiE04); 28,600–35,200 birds in Britain in 2002 (Rowell & Spray 2004)
Status summary
Mute Swan populations, which had been fairly stable since the 1960s, have increased progressively since the mid 1980s, perhaps reflecting warmer winter weather and the replacement of anglers' lead weights, which had earlier caused many casualties, with non-toxic alternatives (Rowell & Spray 2004). WBS plots, likely to be a preferred habitat for breeding swans, show a more moderate rate of increase than CBC/BBS. Winter trends as measured by WeBS have shown a parallel upturn (Banks et al. 2006). The reductions in breeding performance, although statistically significant, may be to some extent artefacts of the relatively small and perhaps unrepresentative annual samples in the 1990s. The recent change of conservation listing from green to amber is unconnected with its UK trend.
 

Population changes
CBC/BBS UK graph
 
Table of population changes for Mute Swan

Source Period
(yrs)		 Years Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
CBC/BBS UK 38 1967-2005 74 216 60 632    
  25 1980-2005 105 159 86 331    
  10 1995-2005 218 19 2 51    
  5 2000-2005 238 -8 -20 6    
CBC/BBS England 38 1967-2005 64 193 29 548   Small CBC sample
  25 1980-2005 89 148 72 272   Small CBC sample
  10 1995-2005 186 9 -3 30    
  5 2000-2005 198 -2 -11 19    
WBS waterways 30 1975-2005 44 56 2 134    
  25 1980-2005 47 36 -1 88    
  10 1995-2005 56 10 -8 41    
  5 2000-2005 49 -7 -18 10    
BBS UK 10 1995-2005 203 17 -2 51    
  5 2000-2005 234 -7 -17 10    
BBS England 10 1995-2005 172 5 -9 29    
  5 2000-2005 195 0 -12 20    

BBS acknowledgement
 
CBC/BBS England graph
WBS UK graph
BBS UK graph
BBS England graph
 

Productivity trends
Table of productivity changes for Mute Swan

Variable Period
(yrs)		 Years Mean
annual
sample		 Trend Modelled
in first year		 Modelled
in 2005		 Change Comment
Clutch size 37 1968-2005 22 None       Small sample
Brood size 37 1968-2005 37 None        
Daily failure rate (eggs) 37 1968-2005 29 Curvilinear 0.62% nests/day 1.52% nests/day 145.2% Small sample
Daily failure rate (chicks) 37 1968-2005 24 None       Small sample
Laying date 37 1968-2005 13 None       Small sample

 
Clutch size graph
Brood size graph
Egg nest failure graph
Chick nest failure graph
Laying date graph

 

 

Insufficient data on CES
available for this species
 

Additional information
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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., Barimore, C., Coombes, R.H.,
Downie, I.S., Freeman, S.N., Joys, A.C., Leech, D.I., Raven, M.J., Robinson, R.A. & Thewlis, R.M. (2007)
Breeding Birds in the Wider Countryside: their conservation status 2007.
BTO Research Report No. 487. BTO, Thetford. (http://www.bto.org/birdtrends)

Pages maintained by Susan Waghorn and Iain Downie: Last updated 3 January, 2008