Wetland winners and losers

Signs of dramatic changes for some wetland birds are reported today as some species reach their highest and lowest recorded population levels in the UK in winter. The latest population figures on wetland birds, and a host of other species, are contained in the State of the UK’s Birds 2011 report published by a coalition of the RSPB, British Trust for Ornithology (BTO), and the Wildfowl & Wetlands Trust. The report provides a ‘one-stop-shop’ for the results of bird surveys and monitoring schemes and projects from across the UK from as recently as 2010.

Overall, numbers of wintering waterbirds have been in shallow decline since the late 1990s, but the underlying story is more complex. One of the greatest losses recorded in the report has been our most familiar duck, the Mallard. Winter numbers have declined by 38% since 1982 and by 22% since 1998. On the other hand, the Shoveler has increased by 27% since 1998.

The Whooper Swan has reached its highest ever levels (increasing by 122% in the last 10 years) but Bewick’s have declined by 44% over the same period.

The reasons for the changes are complex and not yet fully understood. Results from waterbird monitoring schemes in other parts of Europe have shown that some changes are likely to be explained by birds not migrating as far because of milder conditions elsewhere: a phenomenon known as ‘short-stopping’. But for other species, such as the Bewick’s, international cooperation has proven that numbers are declining across northern Europe.

Other species which have declined since 1998 are: Pochard (-46%); Dunlin (-39%); Bar-tailed Godwit (-29%); and Ringed Plover (-26%).

Wintering wetland birds that have increased since 1998, include: Avocet (+95%); Black-tailed Godwit (+53%); and Pink-footed Goose (+27%). The avocet and pink-footed goose have both reached their highest population levels since records began.

Neil Calbrade, WeBS Research Ecologist at the British Trust for Ornithology, says: “This shows the value of continued monitoring of wetland sites through long-running schemes such as the Wetland Bird Survey (WeBS).

“For more than 60 years, WeBS counters have carried out monthly surveys of over one and a half million birds annually which allows us to build up a picture of the fortunes of these waterbirds and how they may be affected by climate change, habitat loss and development."

Richard Hearn, Head of Species Monitoring with the Wildfowl & Wetlands Trust, says: "We are seeing increasingly rapid changes in wintering waterbird numbers in the UK. Some species such as Goldeneye are most likely moving elsewhere, but others such as Long-tailed Duck and Velvet Scoter, are thought to be declining everywhere and require urgent conservation action.

“An icon of the UK migration season, Bewick’s Swans also need continued focus to ensure conservation actions are implemented. And with so many of these migratory birds reliant on our wetlands, the loss of 45% of wetland habitat in the UK in the last 75 years is a major concern.”