Some of our Whitethroats are missing

Whitethroat (Dave Williams)

In western Anglesey at the weekend came the scratchy call of Whitethroats from several hedgerows and patches of scrub. This trans-Saharan migrant has been missing from many of my days out this summer, but while we tend to notice if a familiar bird is absent, it’s harder to assess abundance from memory. Records are important, more so when collected systematically such as through the Breeding Bird Survey, run by the British Trust for Ornithology in association with the RSPB and JNCC.

The BBS shows that Whitethroat numbers dropped by 28% in Wales between 1995 and 2022, in contrast to the UK as a whole. In Scotland, Whitethroat abundance has more than doubled in the same period, while numbers in England increased by 15%.

BBS results for this year won’t be available until next spring, but a crude idea of the state of play is evident from BirdTrack, the online system to which 5.7 million sightings have already been added this year. Occurrence of a species on lists submitted by birdwatchers (known as the reporting rate) gives an idea of how frequently it is encountered. The rate for Whitethroat in Scotland has tracked above the average since mid-May when most Whitethroats arrive, but were 20-30% lower than the Welsh average, and by early July it is more than 50% lower. The deficit is most marked in Anglesey and Gwynedd.
​It’s hard to think why Whitethroats are doing worse in Wales than elsewhere in Britain. Previous fluctuations have caused by lower survival when rains fail south of the Sahara, reducing the abundance of invertebrates in the Sahel region to which many European migrants travel in autumn. But the differences between parts of Britain suggest something on their breeding areas. Let’s hope it is just a blip.

Scarcest sightings at the weekend were a Roseate Tern and Hooded Crow on the Clwyd estuary, both unusual east of the Great Orme. Another Roseate Tern was at Cemlyn, where North Wales Wildlife Trust wardens counted almost 1700 Sandwich Tern and over 300 Black-headed Gull chicks, welcome totals after last year’s bird flu tragedy. A Ruddy Shelduck is off Flint, two Whooper Swans at Porthmadog, and last week’s winds saw Storm Petrels pass Porth Ysgaden and a Sooty Shearwater from a ferry into Holyhead.

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