Contents of report
Breeding Bird Survey
Common Birds Census
Constant Effort Sites
Nest Record Scheme
Waterways Bird Survey
Alerts
Summary
What the categories mean
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MUTE SWAN Cygnus olor
 
Conservation Listings Long term trend

Unlisted/Green
Biodiversity Steering Group Conservation Concern List

UK: Moderate increase
 
Status Summary
Mute Swan populations have increased continually 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 30 1968-1998 20 174 34 403   Unrepresentative? small sample
  25 1973-1998 22 165 23 317   Unrepresentative?
  10 1988-1998 23 73 37 128   Unrepresentative?
  5 1993-1998 27 35 14 69   Unrepresentative?
WBS waterways 23 1975-1998 43 67 21 156    
  10 1988-1998 52 54 28 97    
  5 1993-1998 60 27 14 43    
BBS UK 5 1994-1999 159 16 -3 38    
BBS England 5 1994-1999 139 -15 -28 1    
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 30 1968-1998 19 Linear decline 5.88 eggs 5.09 eggs -0.79 eggs Small sample
Brood size 30 1968-1998 34 Curvilinear 4.47 chicks 3.74 chicks -0.73 chicks  
Daily failure rate (eggs) 30 1968-1998 26 Curvilinear 0.0086 nests/day 0.0556 nests/day 0.047 nests/day Small sample
Daily failure rate (chicks) 30 1968-1998 21 None       Small sample
Laying date 30 1968-1998 12 None       Small sample
 
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)

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Last updated: 19 April, 2001

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