Some urban birds used to be cliff nesters before towns and cities existed: House Martins and Swallows, Swifts, Barn Owls, and some seagulls. Kittiwakes are birds of the open seas. They do not use rubbish tips to feed, like other gulls, and they are only brought inland when gales or storms push them out of their preferred habitat. They only come to land to breed and cliffs are great magnets for them: they will perch their nests made of grass, mud and seaweed in small ledges. In the cliffs where they nest their constant calls contribute to create a wonderful atmosphere in the breeding season.
Buildings on seaside towns offer them artificial cliffs, safe from predators. We watched the large Kittiwake colony in Scarborough. Some nest in luxury, single occupation ridges on the ornate walls of the Grand Hotel.
Others cram in apartment buildings, having to share their window ledges with two other pairs. These were making such a rattle I couldn't imagine the human occupants of the building would get much sleep.
The lower kittiwake classes have to content themselves with a nest under the bridge. One adult fed little fish to the adult on the nest in the middle.