Habitats: New Report Reveals Troubling Declines in UK’s Wintering Waterbirds​

23 May 2025
By James Hamilton
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Long-tailed ducks by Sarah Kelman

​The UK plays a crucial role in supporting internationally significant numbers of wintering waterbirds. Vital monitoring programmes - the Wetland Bird Survey (WeBS) and the Goose and Swan Monitoring Programme (GSMP), continue to provide the data needed to inform conservation policies for these species.

With contributions from over 3,800 dedicated volunteers, these surveys deliver an annual snapshot of bird populations across the UK’s coasts, estuaries, lakes, reservoirs, and rivers. Ducks, geese, swans, waders, and other waterbirds are all closely tracked as they reside or pass through these critical habitats.

The 2023/24 WeBS report highlights ongoing changes in the status of many of these species, including worrying declines in some of the UK’s most familiar waterbirds.

Bird Flu's Lasting Impact

​Highly Pathogenic Avian Influenza (HPAI), or bird flu, has caused significant mortality among wild birds in recent years, particularly those that gather in large flocks such as seabirds and wildfowl. Among the hardest hit are Mute Swans, a species well-known to the public.

Mute Swans were the most frequently confirmed bird flu cases among wild birds in 2021 and the second most in 2022. A newly published study estimates that approximately 1,000 Mute Swans were found dead due to the virus between 2021 and 2023.

The latest WeBS findings show that Mute Swan numbers across England, Scotland, and Wales have plummeted to their lowest levels in 25 years. While it is not yet clear to what extent this decline is directly attributable to avian influenza, the trend highlights the vulnerability of even common species to disease and environmental pressures.

Spotlight on Protected Sites

The latest WeBS report also includes an update on ‘WeBS Alerts’, a periodic review of how waterbird populations are faring within the UK’s legally protected sites versus the wider landscape.

The findings show consistent and concerning declines for several species on these protected sites. Seaducks such as Scaup, Velvet Scoter, and Long-tailed Duck have seen declines of more than 70%. Other species in trouble include Goldeneye, Curlew, Grey Plover, and Ringed Plover.

These declines mirror broader trends linked to climate change, habitat shifts, and other large-scale pressures, underscoring that even protected sites cannot shield species from every threat.

However, there are signs of conservation success. In more than half of the 472 species assessments conducted, populations within protected sites were either outperforming regional or national trends or recovering from previous declines. Increasing numbers of Avocet and Black-tailed Godwit, for instance, are now spilling into less optimal wetland areas as their core populations grow.

Assessing the quality and role of protected sites is essential for guiding future conservation efforts and ensuring these refuges remain effective havens for vulnerable species.

Expert Voices

Dr Teresa Frost, Head of Waterbird Monitoring at the BTO, emphasized the importance of continued tracking:
“We live in a rapidly changing world, and wetland environments are exposed to all kinds of pressures. Monitoring is essential not only for tracking recovery from diseases like bird flu but for understanding the full range of threats that affect waterbird numbers.”

Simon Wotton, Senior Conservation Scientist at the RSPB, highlighted the broader environmental implications:
“Many WeBS-monitored sites are of international significance. The sharp declines in species like seaducks and waders point to the wide-reaching impact of climate change on bird populations and migration patterns.”
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Dr Kirsi Peck, Evidence Specialist at JNCC, reinforced the need for vigilance:
“In a world increasingly shaped by climate change, habitat loss, and disease, we cannot take our wintering waterbirds for granted. Programmes like WeBS and GSMP provide vital insight and help shape effective conservation strategies for these crucial species.”

Read the full 2023/24 WeBS Report.
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This year’s WeBS Alerts were funded by Natural England and WeBS partners.
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