The House Martin is one of the iconic birds of summer. They build nests below the roofs of the visitor centre and outbuildings. They fly over the lawns and the lake to catch insects and then fly up to the nests to feed their young. The Sand Martin is similar, but has a dark collar and is more of a brown colour, lacking the House Martin's blue sheen. The House Martin also has a white patch on its back, between the tail and wings.