House martin
The house martin arrives in the UK and leaves again in October to winter in sub-Saharan Africa and tropical Asia. It is a small, stocky, black and white bird with short, white-feathered legs. It has blue-black upperparts, brown wings, white rump, and white underparts. The short tail is forked, and the wings are triangular.
Its flight is fairly stiff and holds its wings angled back during active flight and stretched out when gliding. It can be seen flying over suburbs, rural areas, and lakes, coming to rest on roofs and wires, or swooping low onto puddles and other bodies of water. It has a short, dry call and twittering song.
House martins nest under the eaves and gables of the ends of buildings. The nest is closed on the top and has a small side entrance hole. Small groups will gather together to collect mud with which to build their nests. House martins produce 2 or 3 broods a season. Juveniles can be seen from late April.