roof

House martin Delichon urbicum at nest in the eaves

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

Waterloo International Station diagram showing how the roof echoes the curve of a pangolin Illustration from “30 Animals that made us smarter” by Patrick Ayree (BBC Books)

House martin Delichon urbicum coming to feed chicks in a nest under the eaves of a roof, small vignette