The Slender-billed Gull is rarely reported in Iberia away from its few breeding colonies in Andalucía and the Levant and the nearby coasts. It was a rarities committee bird in Portugal until 2008 but has since become a frequent presence in coastal Algarve. There are few published records from anywhere else in Portugal or from NW and Atlantic coastal Spain. I was therefore surprised to see a flock of seven adults flying north at the Ría de Aveiro, south of Porto, Portugal on 13 May. I then found four adults resting and feeding on the Spanish side of the Rio Miño estuary (the northern Portuguese/Spanish border) on 18 May and have learned of two appearing further north, at A Coruña, earlier this month. Evidently a small influx has occurred into the region. Any further records of this species away from its regular easterrn and southern sites are of interest and would be welcomed by SPEA or SEO/Birdlife.