Spring migration of birds is still underway, unusual for the end of May. Cuckoos, Wood Warblers, Garden Warbler and Whinchat are among those seen on Bardsey at the weekend, with 49 Spotted Flycatchers there on Sunday and 11 at South Stack on Monday. More, along with Tree Pipits, Redpolls and Siskins paused on the Great Orme, and I watched dozens of Swallows flying over the waves at the southern tip of the Isle of Man, that would have left north Anglesey a couple of hours earlier. A northerly airflow for much of the month is thought to be the reason for the delayed arrival. Other sightings include a pair of Avocets at Cemlyn, Serin over RSPB South Stack, Wood Sandpiper and Black-necked Grebe at Llyn Trawsfynydd,l and two Cranes over Llangybi, near Pwllheli, then south over Bardsey on Friday.

Wildlife Trust wardens at Cemlyn, Anglesey, reported the first Sandwich Tern chick hatched on Monday, after announcing that breeding numbers were half last year’s total and Highly Pathogenic Avian Influenza had been confirmed at the colony. The UK Government reports that Black-headed Gulls and Common Terns tested positive for bird flu on Anglesey and in Flintshire. Elsewhere in Wales, images from Grassholm in Pembrokeshire show significant gaps in the huge Gannet colony but RSPB Cymru reports no obvious signs of disease yet this year, and Montgomeryshire Wildlife Trust reopened its Llyn Coed y Dinas reserve at Welshpool following a suspected outbreak in Black-headed Gulls.

After last week featuring the places with most bird sightings on BTO’s Birds on Your Doorstep, where has recorded the fewest species in the last decade? A sliver of coast north of Barmouth had just three regularly occurring species, but 63 when passage migrants were included. Two upland areas each had 14 regularly occurring species, the 10km square dominated by Aran Fawddwy between Bala and Dolgellau, and around Llanarmon Dyffryn Ceiriog in North Berwyn. Perhaps the biggest contribution we could all make to bird data in Wales is to spend time recording birds in places that others don’t. If you want to know where to start, sign up to BirdTrack to make your sightings count.

​Yellow Wagtail is, sadly, now a rare breeding species in North Wales, but small numbers pass through on migration, including distinctive forms that breed elsewhere in Europe. Identification can be a challenge, however, especially as hybrids are not uncommon. A Grey-headed (Yellow) Wagtail, en route to Scandinavia, was at Morfa Nefyn earlier in the month, identified following a post on social media. Another visited Cemlyn last week, along with a Blue-headed bird from central Europe, plus Little Gull, Tree Sparrow and Hen Harrier. Other sightings include Wood Sandpipers near Chwilog and RSPB Burton Mere Wetlands, Turtle Dove at Silver Bay, near Rhoscolyn, 59 Spotted Flycatchers on Bardsey, and a Black Kite reported over Esclusham Mountain, near Wrexham.

Bird sightings collected by volunteers over the last 50 years and collated by the British Trust for Ornithology show how populations have changed. The headline is pretty stark: the UK is home to a net 73 million fewer breeding birds than in 1970. The total declined from 232 million birds to 159 million. The total losses - of species such as Skylark and Yellowhammer - are actually greater, because they are partly offset by increases in species such as Wren and colonising species such as Cetti's Warbler. Visit Birds on your Doorstep, enter a postcode and call up a summary of changes in that 10-km square. In the coming weeks, thanks to Dr Simon Gillings at BTO, I’ll pick out some of the key findings in North Wales.

Where in the region are the most bird species recorded? Perhaps it’s no surprise that it is coastal headlands and islands, which attract migrant birds and birders in equal measure. Ynys Enlli/Bardsey, Uwchmynydd and Aberdaron is the top-scoring grid square, with 257 species in the last 10 years – 40% of the total ever recorded in Britain. Squares SH39 on the north Anglesey coast, including Cemlyn, has recorded 240 species and the north of Holy Island, with 236, is close behind, containing well-watched sites such as RSPB South Stack and Beddmanarch Bay.

More results from Birds on your Doorstep will be published here in the coming weeks...

Bardsey Bird & Field Observatory warden Ed Betteridge had a surprise last Tuesday when one of the first birds he found on the island was a Song Sparrow. This streaky songbird, not closely related to our House Sparrow, is resident across the northern states of the USA, but look quite different in each part of North America, caused by local environmental conditions not genetics. Song Sparrows that breed in southern Canada leapfrog their sedentary relatives to winter in the mid West and Gulf Coast states. It is only the 11th Song Sparrow found in Britain, and with the exception of one in Yorkshire in 1964, all were found around the Irish Sea or on Fair Isle, just south of Shetland. This may point to it riding on a ship for all or part of its voyage. This was the second Bardsey record, coming 53 years almost to the day after the first, but unlike the 1970 visitor, this was a one-day wonder.

News of the Song Sparrow rather overshadowed another trans-Atlantic arrival, an American Golden Plover at Cemlyn, on Anglesey. Other unusual birds last week include a Quail at Sealand, Wood Sandpiper at Cemlyn, Garganeys at RSPB Cors Ddyga and Tree Sparrows at RSPB South Stack. A White-tailed Eagle reported flying up the Dee valley near Holt on Sunday may be a young bird released in southern England as part of a reintroduction project.

The latest Wetland Bird Survey results show big declines of several species in Wales in the last 10 years. Non-breeding populations of Pochard fell 66%, Bar-tailed Godwit by 64%, Grey Plover by 52%, Coot by 42% and Red-breasted Merganser by 37%. There were positive increases in Whooper Swan, Gadwall, Eider, Pale-bellied Brent Goose, Turnstone and Little Egret in Wales over that period. The Dee estuary remains the fourth most important wetland in the UK for waterbirds, with another Liverpool Bay estuary, the Ribble, in second place.

Many of our summer migrants have now arrived, with a rush of warblers and Swifts in the last week, and Spotted Flycatchers are due now, usually the last to make it to Britain. At Cemlyn lagoon, North Wales Wildlife Trust wardens report that Sandwich Terns and Black-headed Gulls are on nests, that Arctic Tern numbers are higher than usual but have yet to lay eggs, and a Roseate Tern visited on Sunday.

Rarity of the week was a Black-crowned Night Heron on the Afon Wen near Chwilog. Wood Sandpipers visited RSPB Cors Ddyga and Llyn Trawsfynydd last week, and a Short-eared Owl was over Gronant and Talacre, where Little Terns are starting to nest and Denbighshire Council and RSPB wardens are reminding dog-walkers to keep their pets on a lead. Two Dotterels were on the summit of Foel Fras and 10 on Carnedd Llewellyn, a brief pause en route to a Scottish or Norwegian mountain-top. A couple of Avocets stopped on the Clwyd estuary last week and a Black-winged Stilt and Spoonbill visited several sites on the Dee estuary.

The results of January’s RSPB Big Garden Birdwatch show House Sparrows topping the Welsh chart once again, with numbers higher than elsewhere in the UK. There were 49 species recorded in Welsh gardens over the Birdwatch weekend, with the biggest changes including a 68% increase in Blackcaps compared to 2022 and a 41% increase in Long-tailed Tits. Redwing, Fieldfare and Goldcrest sightings were also up. Nuthatch numbers were down by more than 20% and Jays by a massive 73%, which reflects the abnormal winter numbers in 2022 that followed a huge movement into Wales the previous autumn. The number of Pheasants recorded in gardens was also down by more than 20%, which may reflect lower volumes being released by shoots last year because avian influenza meant eggs and poults were more difficult to obtain.   
 
The GWCT Big Farmland Bird Count results were also published recently, which recorded 95 species in Wales during two weeks in February. Robin, Blackbird and Carrion Crow were seen on more than 50% of farms participating.

Text updated on 9 May with additional information about 10 Dotterels in the Carneddau on Sunday 7th.

​The appearance of a couple of Black-winged Stilts on the Clwyd estuary last week may be a consequence of water shortage in North Africa and Iberia. These elegant wading birds should be nesting on saltpans and lake edges around the Mediterranean, but occurred at more than 30 sites across Britain and Ireland this week, including one at RSPB Burton Mere Wetlands. Stilts have bred sporadically in Britain, but these were the first sightings in North Wales for 26 years. Another Mediterranean wetland species, Black-crowned Night Heron, was reported at more than 60 sites in Britain & Ireland last week.

A two-year drought, exacerbated by irrigation diverting water to vegetable and soft-fruit farming, has led to the world-famous Coto Doñana drying out. Home to rare waterbirds including Marbled Duck, Crested Coot and thousands of Greater Flamingos, it is further threatened from proposals by Andalucia’s government to allow irrigation for strawberries and blueberries grown as out-of-season exports to northern Europe.

Other rare visitors to North Wales include a Pectoral Sandpiper at RSPB Cors Ddyga, Long-tailed Duck on the Afon Glaslyn at Porthmadog, two Dotterels and a Blue-headed Wagtail on the Great Orme, Little Gull on the Alaw estuary and two Avocets at Gronant. Among migrants on the North Wales coast was a Corn Bunting on the Great Orme, now a rare bird in Wales that is just hanging on as a breeding species on the Shropshire border. Whinchats, Whimbrels and Swifts are now arriving across the region.

Tragic scenes are unfolding near Welshpool, at a wetland home to one of the most important Black-headed Gull colonies in Wales. The species is among those worst hit by ‘bird flu’ across northern Europe so far this year, and is suspected to be responsible for the death of dozens of gulls at a nature reserve in the Severn Valley and meres across Cheshire. Black-headed Gull is already on the Red List of conservation concern in Wales because of a huge decline in the breeding population, and avian flu could push it to the brink of extinction.