​Roseate Terns are Britain’s rarest breeding seabird, so it is always special to see them in North Wales. Two adults and a juvenile were at Cemlyn Bay on Sunday, the metal leg rings on one of the adults denoting that it had been raised on Rockabill, the island in Dublin Bay that is the most important site for the species in Europe. Another Roseate Tern was at Rhos Point on Monday. Thankfully, the Irish colony appears to have avoided the huge outbreak of high pathogenic avian influenza (HPAI) that is having devastating consequences for seabird colonies in Scotland and eastern England. Terns are also fledging from Welsh colonies, including a pair of Roseate Terns from the Skerries, off the northwest coast of Anglesey. That is very welcome news, as the only significant colony in Britain, Coquet island in Northumberland, has been badly affected by HPAI, which has killed at least a quarter of the adult population.

A Black Tern was an unusual visitor off The Skerries at the weekend, while other scarce visitors to Anglesey included a Ring-necked Duck and Purple Heron at RSPB Valley Wetlands, Curlew Sandpiper and Little Stint on the Alaw estuary, and a Ring Ouzel near Bryngwran. The heron was the 200th species to be recorded on the island this year, reports the Anglesey Bird News blog.

Mediterranean Gulls continue to arrive from the southeast, with 43 on the Alaw estuary, nine at Rhos Point and eight at Cemlyn and on the Afon Glaslyn. Yellow Wagtails have been spotted at RSPB Conwy, with a count of 57 Little Egrets and a couple of Great White Egrets there. Waders are arriving daily, many still in their colourful breeding garb: several Turnstones and a Knot at Rhos Point looked were freshly in on Monday, as were Greenshanks at Morfa Madryn and the Alaw.

Thank you for the positive response to last week’s plea to help Hawfinches by suspending provision of waters and feeders in gardens in Meirionnydd. If you missed the story, click here.

RSPB Cymru and BTO Cymru have called on householders in Meirionnydd to suspend providing food and water for birds for the remainder of the summer. This area includes the towns of Blaenau Ffestiniog, Bala, Penrhyndeudraeth and Barmouth. The move is an effort to reduce the risk of Trichomonosis spreading in the Hawfinch population. People have been reporting sick and dead Hawfinches in gardens throughout spring and summer in the Dolgellau area, making it the worst year since studies began 10 years ago.

Hawfinch is a scarce and localised woodland breeding bird that is attracted to sunflower seeds provided in gardens. The area around Dolgellau holds one of the five most important populations in the UK and is one of the two principal breeding areas in Wales.

Trichomonosis is the primary cause of a 79% decline in Greenfinch in Wales over the last 10 years, and a 38% decline in Chaffinch, so a similar decline could be catastrophic for the Hawfinch population. Trichomonosis causes lesions in the throat, which makes it progressively hard for the bird to swallow food. Sick birds may be lethargic, fluffed-up, regurgitate food, salivate excessively or show laboured breathing. It is bird-specific, and does not pass to mammals, including humans.

Diseases can be spread by birds congregating at bird feeders and water. Householders elsewhere in North Wales are reminded to maintain good hygiene where food and water are provided, and to withdraw food and fresh water if sick birds are seen. Birds will disperse across the countryside where they are less prone to transmitting disease. Despite the dry weather, there is plenty of fruit, nuts and fresh water in Meirionnydd during the summer. In this area, householders are advised not to provide bird baths to reduce the risk to the survival of Hawfinches. To find out more about Hawfinch studies in North Wales, see this Daily Post article from 2017.

The first of a new generation of North Wales Ospreys took to the air at the weekend, with the maiden flight of the eldest chick in Nant Glaslyn. Three Spotted Redshanks were at Connah’s Quay nature reserve last week, a Marsh Harrier has spent a week on Bardsey, and a small number of Mediterranean Gulls are scattered around the coast.

One of the joys of sleeping with open windows has been waking to the sound of Swifts that nest above our roof soffits. The adults have been screaming down the street until sunset, and then at first light drop from the nest above the bedroom window, off to find flying insects to feed their young. We came home recently to the sad sight of a young Swift that fell to its death on the doorstep, just days before its maiden flight. Despite this disaster, all three nests remain active within our eaves. The chicks should fledge in the coming days, destined to remain airborne until 2024, when we hope to welcome them back. I added these nests, and others spotted in recent days, to swiftmapper.org.uk, so the information is available to those working to save Swifts.

The prospect of record-breaking temperatures should concentrate all our minds on the need for urgent action to tackle climate change. New research by the British Trust for Ornithology adds another example to the growing list of rapid changes facing nature. Willow Warblers have become scarcer in England in recent years but more common in Scotland, and climate has been a suspected factor. The study shows that optimal average ground temperature during the breeding season is 11° Celsius for Willow Warblers, and 13.5°C for the similar Chiffchaff. In just over 20 years to 2017, the breeding season temperature averaged 12.7°C in England where Willow Warblers are declining and 10.2°C in Scotland where they are increasing. Although the study didn’t analyse data in Wales, we might expect a similar northward shift, and that further temperature increases will be bad news for Chiffchaffs too. The heatwave should remind us to ensure we maintain water in gardens to help wildlife, but also to ensure that birdbaths are cleaned regularly to minimise the risk of transferring disease.

Waders are trickling back from the Arctic as the breeding season draws to a close. Whimbrels from Iceland, Green Sandpipers from Scandinavia and Greenshanks from Fennoscandia are at the forefront of migration, while Curlews landing on our beaches may have come from elsewhere in Britain, or as far east as Finland and Poland, while Great White Egrets on the Conwy estuary and at RSPB Cors Ddyga may have originated from France or the Low Countries.

With its long tail streamers, Roseate Tern is one of our most elegant seabirds and one of Britain’s rarest, so the sight of dead birds on the tideline and confirmation of high pathogenic avian influenza (HPAI) at our only colony was a bitter blow this week for those who have spent 20 years helping its population to recover. Just 150 pairs breed on Coquet Island in Northumberland, with a handful of nests elsewhere in the UK, including an occasional one on Anglesey. Seabird die-offs have been witnessed in Germany, The Netherlands, and France, as well as the south coast of England.

It is the latest bodyblow for seabirds, already struggling with the twin impacts of climate change and long-term declines in fish stocks. The list of species and number of colonies affected is lengthening. Initially confirmed in Great Skuas in Scotland, each day through June has seen more images of dead and dying birds, including Gannets, Sandwich and Common Terns, Guillemots and Razorbills. Testing to confirm HPAI has been sporadic, but the scale of gaps in colonies that should contain thousands of birds shows this is the biggest outbreak ever in wild birds. The disease jumped from farmed poultry to wild birds in east Asia in 2003, and more recently in Central Asia. Migration has brought HPAI to our shores with devastating consequences.

Seabirds around the Irish Sea have been less affected to date, but it is impossible to know how this will play out. Wardens at tern colonies in Anglesey and Denbighshire report that chicks are fledging, and it is hoped that at least some will move way from mass gatherings in which the disease spreads rapidly. Rockabill island in Dublin Bay holds around 1700 pairs of Roseate Terns, so an outbreak there would be even more catastrophic.

Meanwhile, the RSPCA has stopped accepting sick or injured seabirds to its rescue centres and several islands are closed to visitors, including the Farnes in Northumberland. The public are being urged not to touch dead or sick birds nor allow dogs to do so, and to ring Defra on 03459 335577 if you find three or more dead waterbirds, seabirds or raptors.

Recent notable sightings include a Cattle Egret on the Alaw estuary, Quail at RSPB Cors Ddyga, up to 40 Mediterranean Gulls on Porthmadog’s Llyn Bach, Great White Egret and Green Sandpiper at RSPB Conwy, and a young Cuckoo at Cemlyn.