Dipper: the canary of Welsh rivers

Dipper feeding chick (Jason Hornblow)

A report published today shows that almost half of the commonest native bird species are declining in Wales, trends in the wrong direction for Welsh Government’s ambition to bend the curve of loss by 2030. Curlew, Swift and Yellowhammer are among species that have declined by at least three-quarters in Wales since 1995. Breeding Bird Survey results from the BTO, JNCC and RSPB also highlight several river species in trouble: Dipper numbers in the UK have fallen by 32% since 1998.

Reliant on aquatic invertebrates, Dippers are an excellent indicator of water quality, so what does the decline say about the state of our rivers, or for other life such as fish that also depend on insects? Pioneering research on Dippers and Grey Wagtails in Wales during the 1980s showed the impact of sulphur deposition from acid rain. Numbers recovered when air pollution was tackled but nitrate and phosphates washed into streams from farmland, and pollution from sewage treatment overflows may have sent that recovery backwards. A recent Dutch study shows that ecosystem function risks collapse because of neonicotinoid insecticides.

The urgency was emphasised by the Future Generations Commissioner’s recent report that criticised politicians and public bodies for applying short-term fixes to long-term problems. Highlighting that 60% of Welsh rivers recognised for their nature importance are failing to meet water quality targets, the Commissioner called for government and institutions to prioritise wildlife with “a statutory incentive required to ensure that nature recovery is built into decisions on infrastructure, housing, flood prevention and pollution control”.

​With most spring migrants back on their breeding grounds, birders’ attention turned to continental species that “overshot” their intended destination. A Black Kite was over Aberdaron and Bardsey, with a Black Stork pushing farther into Pen Llŷn, near Rhoshirwaun, on Sunday, and a Hoopoe in a Criccieth housing estate. Flypasts reported included a Montagu’s Harrier reported over Rhoscolyn and a Bee-eater over the Great Orme. A couple of Spoonbills passed Wylfa Head, with another on the Inland Sea, and perhaps the same at Pwllheli on Thursday. Blue-headed Wagtails were on Bardsey and at Cemlyn, where a Little Gull and Roseate Tern joined the colony and a Curlew Sandpiper paused on migration. A Wood Sandpiper dropped into Gronant, an Avocet at Porthmadog, four Cattle Egrets are at Shotwick and a Quail calls at Marford.