All the available data, largely unpublished, are assembled for sea-birds breeding in African waters, about 36° N.-36° S. An ill-defined breeding season by any species at any station is exceptional. North of the Equator practically all sea-birds breed in spring or summer. South of the Equator there is much more variation. Round the Cape there is a good deal of mid-winter breeding, mainly in stations affected by the warm Agulhas current. On the east coast most of the breeding takes place in the period June-August from the Gulf of Suez (27° N.) to the mouth of the Zambesi (19° S.) and beyond, i.e. in the hottest months north of the Equator and the coolest months south of it.