Some birds use buildings as nesting sites in urban areas. Sheltered led provide elev places wh adults c raise yo above bu streets a nearby pa supply ins and ot food during warmer months. For species that naturally occupy rocky cliffs, a building can offer familiar physical features in an unfamiliar setting. The surrounding landscape still matters: a suitable ledge is less useful if food is difficult to obtain. Nesting success therefore depends on both the structure and the resources within reach. Changes to building surfaces can alter these opportunities even when the number of buildings stays the same.

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