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GREY HERON
Ardea cinerea
Grey Heron © Mike Weston
 
Conservation listings

Europe: no SPEC category, secure
UK: Green

Long-term trend
UK, England, Scotland: moderate increase
Wales: shallow increase
 
Status summary

The BTO Heronries Census, which has monitored Grey Herons since 1928, shows the species to be more abundant now than ever before. The effects of harsh winters, which induce severe mortality in this species, are clearly visible in the long-term trend. The general increase that underlies these fluctuations may stem from reduced persecution, improvements in water quality, the provision of new habitat as new lakes and gravel pits mature, and increased feeding opportunities at freshwater fisheries (Gibbons et al. 1993, Marchant et al. 2004).

The data for Scotland are likely to underestimate the populations there by a relatively small amount because certain parts of the country have never been surveyed for the scheme. Results of the 75th National Heronries Survey: 2003-3004 will help to assess this and will provide a new estimate for the total number of herons in the UK.

 
Herons UK graph
 
Table of population changes for Grey Heron
Source Period
(yrs)
Years Plots
(n)
Change
(%)
Lower
limit
Upper
limit
Alert Comment
Heronries UK 71 1929-2000 282 66 . .    
  25 1975-2000 422 13 . .    
  10 1990-2000 465 14 . .    
  5 1995-2000 514 8 . .    
Heronries England and Wales 71 1929-2000 236 74 . .    
  25 1975-2000 332 16 . .    
  10 1990-2000 373 18 . .    
  5 1995-2000 406 9 . .    
Heronries England 71 1929-2000 201 72 . .    
  25 1975-2000 268 18 . .    
  10 1990-2000 310 18 . .    
  5 1995-2000 341 8 . .    
Heronries Scotland 69 1931-2000 35 71 . .    
  25 1975-2000 53 -6 . .    
  10 1990-2000 53 21 . .    
  5 1995-2000 71 27 . .    
Heronries Wales 65 1935-2000 38 20 . .    
  25 1975-2000 64 -3 . .    
  10 1990-2000 63 8 . .    
  5 1995-2000 65 15 . .    
BBS UK 8 1994-2002 477 32 18 46    
BBS England 8 1994-2002 387 8 -4 21    
BBS Scotland 8 1994-2002 41 113 37 229    
BBS Wales 8 1994-2002 35 23 -18 84    
BBS acknowledgement
 
Census of England graph
Census of England & Wales graph
Census of Scotland graph
Census of Wales graph
BBS UK graph
BBS England graph
BBS Scotland graph
BBS Wales graph
 
Table of productivity information for Grey Heron
Variable Period
(yrs)
Years Mean
annual
sample
Trend Predicted
in first year
Predicted
in last year
Change Comment
Brood size 33 1968-2001 44 Curvilinear 2.52 chicks 2.23 chicks -0.29 chicks  
Daily failure rate (eggs) 33 1968-2001 16 None       Small sample
Daily failure rate (chicks) 33 1968-2001 29 Linear decline 0.0599 nests/day 0.0007 nests/day -0.0592 nests/day Small sample
Laying date 33 1968-2001 31 Linear decline day 98 day 73 -25 days  
 
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
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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