After nine months of flight since they left their nest, Swifts were over Corwen, Llanfair TH, RSPB Conwy and Aber Ogwen at the weekend. They use the same nest site in roof spaces each year, but scaffolding can prevent access to their homes. The RSPB has reminded householders and building companies that active nests of all species are protected by law and encouraged people to report screaming parties of Swifts and nest sites on the swiftmapper.org.uk website. Records can also be added to North Wales Wildlife Trust's Swift Recovery Project on the Cofnod website. 

Meanwhile, the Senedd Petitions Committee urged Welsh Government to take a cross-departmental approach to a call by more than 10,000 people for Swift Bricks to be mandatory on all new buildings in Wales.

In other migration news, Ring Ouzels have been seen from more sites than usual away from their Eryri breeding areas. These are probably birds moving farther north, but as we move into May, any Ring Ouzels showing evidence of breeding behaviour should be reported to county recorders, especially in Denbighshire where summer records are now scarce. Yellow Wagtails adjacent to the River Dee near Sealand include at least one of the continental Blue-headed form.

Groups of Whimbrels rested on their journey to breed in Iceland; larger groups included 80 on Traeth Lafan at Wig, 42 at Carmel Head and 30 on the Glaslyn from Porthmadog Cob. While most waders pause at the coast, one prefers the high life. Six Dotterels were on the western slope of Carneddau Llewelyn, the second highest summit in Wales, on Sunday, en route to Scotland or Scandinavia.

A White Stork flew over RSPB Burton Mere Wetlands from across the Welsh border and six Cattle Egrets remain beside the main road north out of Valley on Monday. Most winter visitors have departed, although the Menai Strait’s Kumlien’s Gull and Black-necked Grebe were at Aber Ogwen last week, from where an Egyptian Goose departed north over Penmon Point on Monday. 

The appearance of a Redpoll from the high Arctic seemed appropriate during a chilly Easter that broke weeks of dry and sunny weather. The bulky finch, nicknamed ‘snowballs’ by some birders, was found by Bardsey Bird Observatory staff on Sunday and still present on Monday.

Redpoll taxonomy has been fluid, and somewhat controversial, in recent years. Current genetic analysis ‘lumps’ Arctic, Common and Lesser Redpolls, the last of which nests in British woodlands. Consequently, the Welsh Ornithological Society recently reduced the three species on the Welsh List to one. Observatory warden Steve Stansfield is confident that this week’s sighting is of the Hornemann’s form that breeds in northeast Canada and Greenland, which would be the first ever recorded in Wales. There have been five Welsh records of the other Redpoll (Coue’s) that breeds in the far north, in Scandinavia and Russia, but none for more than 20 years.

Besides an American Wigeon on Anglesey’s Alaw estuary, sightings otherwise had a more southerly flavour: a Purple Heron at Cors Erddreiniog on Anglesey and a Red-rumped Swallow at RSPB Conwy that came down to feed during Saturday’s rain. A pair of Garganey were at RSPB Cors Ddyga, five Cattle Egrets remain at Valley and a Corncrake was reported on the Great Orme. Lesser Whitethroats, Garden Warblers and Whinchats were seen at several sites for the first time this year and there was a notable arrival of Grasshopper Warblers, including a remarkable 19 between Prestatyn and Gronant.

Ospreys in the Glaslyn valley laid eggs last week, but there has been high drama at Llyn Brenig where two males tussle for the attentions of the nesting female, one of which evicted the two eggs already laid. An Osprey, almost certainly colour-ringed as a nestling in Scotland, caught and ate a fish in the Conwy estuary, delighting visitors to the adjacent RSPB nature reserve.

​In a week that was warmer and drier in North Wales than parts of the Med, some of the visiting birds had a southern European feel: a Bee-eater over Rhosneigr, a Hoopoe at Parc Glynllifon, seven Cattle Egrets near Valley and a White Stork that wandered around Anglesey, feeding with gulls behind the plough on a farm near Llyn Alaw. It, or another, was over Gronant on Monday, and later on the Wirral peninsula. A study published recently shows that Iberian breeding storks have lost their migratory urge over the last 30 years. More than 70% now stay in southern Europe through the winter, compared to just 18% in 1995. Tracking shows that birds only travel to Africa in the first winter after they hatch and then become more sedentary, driven by year-round food availability at landfill dumps in Spain and Portugal.

​The first Little Terns were seen at Gronant at the weekend, where Denbighshire Council is appealing for volunteers to help set up the fences that are so essential to keeping predators, dogs and other visitors away from the nests of one of the most productive colonies in Britain.

Other summer migrants arriving before the weather turned inclement included the first Cuckoos at Dyserth last Thursday, and Mynydd Llandygai and the Aber Valley on Saturday, an influx of Willow Warblers on Holy Island, a Blue-headed Wagtail on Bardsey and more than 100 White Wagtails at Cemlyn. A Slavonian Grebe remains in the Menai Strait, a Surf Scoter off Llanddulas with four Velvet Scoters, and a Tree Sparrow sang at Uwchmynydd, on the tip of Pen Llŷn.

Rarest visitor was a Bonaparte’s Gull, present on RSPB Conwy’s lagoons and the adjacent estuary at the weekend. This North American vagrant has occurred in North Wales on fewer than a dozen occasions, and this was the first record in the Denbighshire vice-county used for wildlife recording.
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It's not too late to sign up for the Heathland Bird Survey, which is seeking to find Dartford Warblers between now and June. Later in the summer, evening visits will be required to find churring Nightjars. I made the first of two visits to one of my allocated squares and was pleased to find Dartford Warblers present, a species that is moving north with a warming climate but with only a toe-hold in North Wales. They nest in gorse and heather, so are especially vulnerable to the spate of fires across the region in recent weeks. Volunteers to survey for Dartford Warblers are needed in western Anglesey, Pen Llŷn, the Carneddau and on moorland north of Llangollen. Details at bto.org/our-science/projects/heathland-birds-survey.

Black Grouse surveyors in northeast Wales will hope that the high-pressure system with its clear weather holds through April. Counting birds requires a calm dawn to locate a lek – the gathering that is often a precursor to mating – by the male’s characteristic bubbling call. One bird in Mynydd Hiraethog took the unusual step of displaying on top of a pole carrying low voltage powerlines, caught on video by Dave Parry. Scroll to the bottom of this page to see the clip. Some have speculated that the Black Grouse, which roost in trees to avoid predation, was responding to its own reflection in the glass insulators. Survey volunteers will be scouring the forests and moors, rather than electricity poles, this month to see whether last year’s population increases have been maintained.

Three Hoopoes on Bardsey and one in an Anelog garden were among at least 150 reported in southwest Britain and the south coast of Ireland in recent weeks; a Wryneck on seacliffs across Bardsey Sound made a similar journey from Africa. These overshot their breeding areas in mainland Europe during recent warm weather, as did a Black Kite that flew over my head beside Anglesey’s Llyn Penrhyn on Friday, where the Red-necked Grebe is developing its colourful summer attire. A White Stork wandered widely over Anglesey on Monday and Tuesday, and being unringed was also likely to be a European breeder. Multiple Ring Ouzels were at South Stack and the Great Orme. Other summer migrants included the region’s first Reed Warblers at RSPB Conwy and Gronant on Monday, Sedge Warbler at RSPB Cors Ddyga on Sunday, while Saturday brought a Yellow Wagtail to the Clwyd estuary, Whinchat at Aberffraw and Pied Flycatcher at Llanberis. Common Sandpiper, Tree Pipit and Whimbrel were also recorded in North Wales last week, and eight Little Ringed Plovers paused at RSPB Cors Ddyga. Three Glossy Ibises that flew along Nant Llugwy near Capel Curig were not relocated.

Last week’s call for dog-owners to protect nesting birds by using a short lead prompted readers to remind owners to deposit dog hair in the bin, not to leave it for birds to use as nesting material if dosed with insecticide tick and flea treatments. A study by the University of Sussex showed that several types of insecticide were found in more than 90% of Blue Tit and Great Tit nests sampled, and that a higher number of dead chicks or unhatched eggs were found in nests exposed to the pesticides. Previous studies have highlighted the toxic effects of pet treatments on aquatic life from dogs treated with spot-on, spray or shampoo flea treatments containing chemicals such as fipronil, which was banned for use in agriculture more than a decade ago.