Swallows, on the other hand, dart and glide about in the air, often low to the ground or at treetop height. They often tweet and chirrup from their perches, usually on telephone wires. They, too, like nooks and crannies in old buildings or barns, and build themselves a cup-shaped nest out of mud. They have a distinctive long, forked tail with tail streamers and have a red throat, white underside and a blueish sheen to their heads and backs, so more colourful to spot.
House martins are smaller and have shorter wings than swifts or swallows although they do have a similar forked tail. They have a pure white underside with blue-black upper parts. Just like swallows, house martins collect mud to build cup-shaped nests but they build them outside buildings rather than inside. They nest in colonies, which can amount to dozens of birds in the same place. They are most active in mornings and evenings and zoom around at mid-height, usually in flocks, coming down low over water and fluttering in and out of house eaves, chirruping softly.
