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BTO Blueline
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BTO Blueline
Ardea cinerea
Grey Heron © Mike Weston

• Population

• Productivity

• Additional

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); 12,959 (12,358–13,795) nests in 2008 (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 at any time in the last 80 years. 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). A downturn evident since 2001 seems unrelated to winter weather and is, as yet, unexplained. 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 10,441 Grey Heron nests were counted. The current population estimates for that year, implying that around 3,300 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. Numbers have risen rapidly across Europe since 1980 (PECBMS 2010).
Herons UK graph

1929-2008: 57% (confidence interval 27% to 87%)

Population changes in detail
Demographic trends
Additional information

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This report should be cited as: Baillie, S.R., Marchant, J.H., Leech, D.I., Renwick, A.R., Joys, A.C., Noble, D.G., Barimore, C., Conway, G.J., Downie, I.S., Risely, K. & Robinson, R.A. (2010). Breeding Birds in the Wider Countryside: their conservation status 2010. BTO Research Report No. 565. BTO, Thetford. (http://www.bto.org/birdtrends)

Pages maintained by Iain Downie, Mandy T Andrews and Laura Smith: Last updated 18.02.2010