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GREY HERON
Ardea cinerea
Grey Heron © Mike Weston
 

• Population
  changes

• Productivity
  trends

• Additional
  information
Conservation listings
Europe: no SPEC category (favourable conservation status in Europe, not concentrated in Europe)
UK: green
Long-term trend
UK, England: moderate increase
Wales, Scotland: shallow increase
UK population size
14,200 nests in 2003 (Heronries Survey 2003: APEP06); 13,316 (12,803–14,192) nests in 2007 (Heronries Census)
Status summary
The BTO Heronries Census, which has monitored Grey Herons since 1928, shows the species to be more abundant in the early 2000s than ever before. The effects of harsh winters, which induce severe mortality in this species (Besbeas et al. 2002), 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). High rates of nest failure at the chick stage were noted in the late 1960s, but not subsequently. The mean laying date has advanced by almost a month since 1968. In the latest special survey of UK heronries, carried out in 2003 to mark the 75th anniversary of the Heronries Census, a record total of more than 10,397 Grey Heron nests were counted. The current population estimates for that year, implying that almost 3,400 nests in the UK were not reported to the survey, allow for known heronries (mostly in Scotland) that were not visited in 2003, but not for the few areas, mainly in Scotland and Northern Ireland, where heronries have never been counted. This issue was addressed by random tetrad searches conducted in 2003 and 2004.
 

Population changes
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 77 1929-2006 312 58 27 84    
  25 1981-2006 487 16 7 26    
  10 1996-2006 564 5 0 10    
  5 2001-2006 586 -3 -7 2    
Heronries England and Wales 77 1929-2006 259 64 29 88    
  25 1981-2006 398 17 8 25    
  10 1996-2006 463 4 -1 9    
  5 2001-2006 475 -3 -7 1    
Heronries England 77 1929-2006 218 63 32 94    
  25 1981-2006 328 18 9 29    
  10 1996-2006 392 4 -1 8    
  5 2001-2006 404 -3 -7 1    
Heronries Scotland 71 1935-2006 44 35 . .    
  25 1981-2006 72 42 . .    
  10 1996-2006 85 42 . .    
  5 2001-2006 92 13 . .    
Heronries Wales 71 1935-2006 40 12 . .    
  25 1981-2006 66 1 . .    
  10 1996-2006 67 3 . .    
  5 2001-2006 69 -6 . .    
BBS UK 11 1995-2006 589 17 7 26   Non-breeders included
  10 1996-2006 608 16 7 25   Non-breeders included
  5 2001-2006 705 -1 -7 5   Non-breeders included
BBS England 11 1995-2006 478 12 1 22   Non-breeders included
  10 1996-2006 492 15 4 25   Non-breeders included
  5 2001-2006 575 6 -1 12   Non-breeders included
BBS Scotland 11 1995-2006 47 38 5 71   Non-breeders included
  10 1996-2006 49 23 -6 50   Non-breeders included
  5 2001-2006 51 -7 -25 9   Non-breeders included
BBS Wales 11 1995-2006 43 5 -17 38   Non-breeders included
  10 1996-2006 45 4 -18 34   Non-breeders included
  5 2001-2006 51 -11 -27 7   Non-breeders included

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
 

Productivity trends
Table of productivity changes for Grey Heron

Variable Period
(yrs)		 Years Mean
annual
sample		 Trend Modelled
in first year		 Modelled
in 2006		 Change Comment
Brood size 38 1968-2006 47 None        
Daily failure rate (eggs) 38 1968-2006 14 None       Small sample
Daily failure rate (chicks) 38 1968-2006 26 Linear decline 5.4% nests/day 0.04% nests/day -99.3% Small sample
Laying date 38 1968-2006 26 Linear decline Apr 8 Mar 11 -28 days 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
BTO blue divider
 

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This report should be cited as:
Baillie, S.R., Marchant, J.H., Leech, D.I., Joys, A.C., Noble, D.G.,
Barimore, C., Grantham, M.J., Risely, K. & Robinson, R.A. (2009).
Breeding Birds in the Wider Countryside: their conservation status 2008.
BTO Research Report No. 516. BTO, Thetford. (http://www.bto.org/birdtrends)

Pages maintained by Iain Downie, Mandy T Andrews and Laura Smith: Last updated 18.02.2009