The behaviour of the male Barbary dove (Streptopelia risoria) in selecting nesting material and transporting it to the nest site is reduced after castration and is restored by treatment with testosterone propionate when castrated males received unilateral intracerebral implants of this androgen. Implants in the anterior hypothalamus, preopitc region, and the area of the ventral neostriatum intermediale were effective in reinstating the collection of nesting material, and in many instances restoration of the behaviour was to levels at or above those observed before castration. Implants in other areas, and implants without hormone, were generally without effect. Although the brain areas from which the gathering of nesting material can be elicited are comparable to those from which courtship displays have been induced in previous studies, it appears that testosterone propionate implants stimulate nesting activities more effectively and more persistently than courtship.