The House Martin is one of the iconic summer birds. They arrive in large numbers to build nests below the roofs and archways. They fly very low over the lawns and meadows to catch insects and then fly up to the nests to feed their young. They build their nests on the outside of buildings, and swallows tend to build inside buildings (such as barns). You can distinguish a House martin from similar species by its all white underside. These are nesting on the walls near the shopping area at Wallington.