Blog by Simon Wotton, Senior Conservation Scientist, RSPB Centre for Conservation Science.

The 37th Wetland Bird Survey (WeBS) report, for 2017/18, has just been published. WeBS is the principal scheme for monitoring the populations of the UK's wintering waterbirds, providing an important indicator of the status of waterbird populations and the health of wetlands.  The survey is run by the British Trust for Ornithology (BTO), in a partnership between the BTO, RSPB and the Joint Nature Conservation Committee (JNCC), in association with the Wildfowl & Wetlands Trust (WWT).

The 2017/18 report documents waterbird counts at 2,847 wetlands across the UK, surveyed by 3195 WeBS counters. WeBS aims to assess the size of waterbird populations, determine trends in numbers and distribution, and assess the importance of individual sites.  Many of the sites monitored under WeBS are of international importance and designated as Ramsar Sites and Special Protection Areas (SPAs), including the four principal WeBS sites over the past five years: The Wash, the Ribble Estuary, Morecambe Bay and Thames Estuary. The Wash remains the most important site for wintering waterbirds in the UK, with 382,523 birds counted in 2017/18, followed by Morecambe Bay with 182,017 waterbirds counted. Counts were generally lower in 2017/18 compared with particularly high counts in 2016/17 caused by the cold weather in Central Europe but were similar to the 2015/16 counts.

Photo: Cover of the Wetland Bird Survey (WeBS) report, for 2017/18

Most goose species are showing increasing population trends, with notable increases for Pink-footed goose and the three Barnacle goose populations. However, the Greenland white-fronted goose and European white-fronted goose are continuing to decline. Mute swan has a fairly stable population and Whooper Swan attained its highest ever index in 2017/18, but Bewick’s swan is continuing a long-term decline in the UK, reaching a record low population index in 2017/18.

The index for several duck species with Eastern European breeding populations, such as Pintail, Wigeon and Teal, dropped back to more typical recent numbers, following high numbers in 2016/17, which were influenced by cold weather on the continent pushing more birds to the UK. Pochard, Mallard and Goldeneye are continuing to decline, with long-term negative trends of 70%, 39% and 61% respectively. Common Scoter recorded another high index, the second highest on record.

Most waders are showing long term-declines, although some, including Dunlin, Oystercatcher and Knot, seem to be showing recent signs of population stabilisation. Curlew continues to decline, recording its lowest index value since 1983/84. Some wader species are increasing; Sanderling had a record high index value in 2017/18, and Avocet and Black-tailed Godwit continue to show strong long-term population increases.

Detailed data on WeBS sites and species are available through the BTO WeBS interactive website ( A copy of the 2017/18 report can be downloaded here.

For more information contact Simon Wotton, Senior Conservation Scientist, or Chiara Ceci, Science Communications Executive, or follow us on Twitter @RSPBScience