A device for deterring birds from roosting or nesting on building ledges and the like having one or more wires (12, 13, 14) linking the opposing faces of two wire attachment means (10, 11) that are fixedly mounted on said ledge or the like. The wire(s) are connected to one wire attachment means (10) by retracting means (15) which adjusts the length and tension on the wire(s) when attached to the opposing wire attachment means (11). When more than one wire is used, the wires may be separately or collectively sprung by means of a spring loaded drum.
