Had a quick walk at Castle Howard with Solomon in a rucsac. A large flock of c100 Sand Martins over the water plus 3 Swallows. When the sun came out, a Willow Warbler started singing close to me in a hedge, my first of the year. Not much on the water of note, apart from two Goldeneye. Several Buzzards noted around the area. A beautiful warm Spring morning, with vibrant green exploding all around.