nest box

Swift Apus apus parent visiting its nest in the eaves of a brick barn

House martin Delichon urbicum at nest in the eaves

Swift Apus apus in flight showing sickle shaped wings and dark stomach

Swift Apus apus and House martin Delichon urbicum comparison of the two birds in flight

Nesting tower for swifts, martins, & bats diagram showing the slots for bats, curved slits for swifts and nests for martins