White Swallow is one in several million

Swallow (Michael Thackeray)

This almost white Swallow stopped Anglesey farmer Phillip Siddall in his tracks while checking his cattle on a drizzly evening near Newborough last week (11 August). Almost unable to believe his eyes, he called on local birdwatcher Michael Thackeray, who took some photographs as it swooped over the pasture with other Swallows and House Martins.

Most birdwatchers know about leucism, the term for a genetic mutation that inhibits the dark melanin pigments from being deposited in the feathers, but that is the limit of knowledge for most of us. I sought the advice of Aurora Tarodo, an ornithologist studying for a PhD at the University of Gloucestershire, who has studied colour pigment aberrations in wild birds. “What an amazing bird!” she said, “it’s the first time that I have seen this mutation in a Swallow”.

“I’d call this non-phaeomelanin schizochroism,” explained Aurora. The bird is lacking phaeomelanin, the body’s chemical that provides reddish colours. Feathers that are usually black, dark blue or red grow as white, or sometimes shades of grey as on the head and rump of this Swallow. The short tail-streamers suggests that it hatched this year, perhaps locally, but it will soon be on its way to spend winter in Africa. It’s impossible to know whether the genetic mutation was passed from its parents to a whole brood or was spontaneous in this individual.

Other sightings at the weekend include a scarce Melodious Warbler at Port Meudwy and a Wood Sandpiper at RSPB Cors Ddyga, while up to 77 Mediterranean Gulls have been on Anglesey’s Alaw estuary. Eight Spotted Redshanks are at Connah’s Quay nature reserve and RSPB Conwy hosted two Ruddy Shelducks and an Osprey on the ground beside the lagoon. Strong winds on Monday brought Great and Arctic Skuas around the coast, and Balearic Shearwaters past Point Lynas and RSPB South Stack.

UPDATE:
Remarkably, within a week of publishing the photograph from Newborough, two more 'White' Swallows were brought to my attention. On Saturday 14 August, a photo of one was posted on a Facebook group in Ireland, seen in Ballinamore, Co. Leitrim, and on Friday 20 August, one was photographed by North Wales birder Marc Hughes while visiting Spurn, East Yorkshire. It is very tempting to believe that all three could have come from the same source to the north, perhaps in Scotland - but we will never know. Click on the thumbnails below to see the images.