Winning Willow Warblers

07 Jul 2016 | No. 2016-28

A population increase of 73% between 1995 and 2014 has been revealed for the Willow Warbler in Northern Ireland in the latest Breeding Bird Survey report. Variations seen in regional population trends within the UK are thought to be largely influenced by changes in climatic conditions, and possibly differences in the timing of migration and distribution once on wintering grounds.

Willow Warbler is bucking the trend in Northern Ireland. BBS trends show statistically significant long-term declines in the UK (-8%) and England (-41%), but an increase of 23% in Scotland and a far larger increase of 73% in Northern Ireland. In Scotland and Northern Ireland, the species is expanding in range, north and westwards, possibly as climatic warming makes such habitats more suitable as breeding sites.

Sarah Harris, BBS Organiser at the British Trust for Ornithology, said “The descending call of the Willow Warbler is a really lovely sound and one that can be increasingly enjoyed in Northern Ireland! Volunteer coverage for the BBS increased in Northern Ireland by 16% from 2014 to 2015. This is very encouraging and our thanks go out to all involved in surveying squares in Northern Ireland and contributing to the 35 species trends for the country. However, we need to expand coverage in Northern Ireland - especially in the west - and would like to hear from any birdwatchers interested in taking part.” 

Neil McCulloch, Ornithologist, Northern Ireland Environment Agency, said “The BBS trend for Willow Warbler in Northern Ireland shows that there are still good news stories to be found amongst our bird community. The results do suggest, however, that we may be entering a period of change in the distribution of some of our commoner birds in response to a changing climate. The extraordinary contribution of BBS volunteers towards tracking these changes is extremely valuable and is particularly important at a time when the resources for monitoring by statutory bodies are increasingly limited.”
Kendrew Colhoun, Senior Conservation Scientist at RSPB Northern Ireland, added “The annual BBS is the primary source of information on the trends of our most common and widespread breeding birds and is keenly awaited each year. The abundance of Willow Warblers choosing Northern Ireland as their summer home isn’t surprising as this survey echoes the pattern we’ve been witnessing in small African migrant birds. As a result of climate change there has been a north and west distribution shift in warblers and Cuckoos. Willow Warblers are increasingly favouring the UK’s northern and western habitats of Scotland and Northern Ireland. This survey reinforces the effect of climate change on where nature makes its home.”

Notes for Editors

  1. Population trends for 35 bird species in Northern Ireland have been calculated in the latest BTO/JNCC/RSPB Breeding Bird Survey (BBS) annual report. BBS is the main scheme for monitoring the population changes of the UK’s common breeding birds.
  2. In 2015, 78 BBS squares were covered in Northern Ireland by volunteers. We are grateful to the Northern Ireland Environment Agency who funded, along with the BTO, training courses with the aim of increasing coverage in Northern Ireland.
  3. The latest report can be found at
  4. The Breeding Bird Survey(BBS) is run by the British Trust for Ornithology (BTO) and is jointly funded by BTO, the Joint Nature Conservation Committee (JNCC) (on behalf of the Council for Nature Conservation and the Countryside, Natural England, Natural Resources Wales and Scottish Natural Heritage), and the Royal Society for the Protection of Birds (RSPB).
  5. The BTO/JNCC/RSPB Breeding Bird Survey (BBS) is a UK-wide project aimed at keeping track of changes in the breeding populations of widespread bird species. The BBS involves around 2,700 participants who survey more than 3,700 sites across the UK, enabling us to monitor the population changes of over 110 bird species. Knowing to what extent bird populations are increasing or decreasing is fundamental to bird conservation.
  6. This important survey is carried out by volunteer birdwatchers throughout the UK, who receive no financial reward or expenses for their efforts. We are indebted to them for their tremendous support.
  7. The BTO is the UK's leading bird research organisation. Over thirty thousand birdwatchers contribute to the BTO's surveys. They collect information that forms the basis of conservation action in the UK. The BTO maintains a staff of 100 at its offices in Thetford, Stirling, Bangor (Wales) and Bangor (Northern Ireland), who analyse and publicise the results of project work. The BTO's investigations are funded by government, industry and conservation organisations.

Contact Details

Sarah Harris
(Breeding Bird Survey Organiser, BTO)

Office: 01842 750050
(9am to 5.30pm)
Email: sarah.harris [at]
Paul Stancliffe
(BTO Media Manager)

Office: 01842 750050
(9am to 5.30pm)
Mobile: 07585 440910 (anytime)
Email: press [at]
Shane Wolsey
(Oversees the BBS for the BTO in Northern Ireland)

Home: 02891 467 947
Email: shane.wolsey [at]
Kathryn Cochrane
(RSPB Northern Ireland)

Office: 028 9049 1547
Email: kathryn.cochrane [at]

Neil McCulloch

Office: 02890 569534
Email: Neil.McCulloch [at]
Images are available for use alongside this News Release. Please contact images [at] quoting reference 2016-July-28
The BTO has an ISDN line available for radio interviews. Please contact us to book an interview Office:01842 750050

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