Clear and present dangers
20th century|Algoa Bay’s Bird Island|arid areas|breed|breeding islands|census|fish stocks|gannet numbers|guano|Ichaboe|Lambert’s Bay|Malgas|Mercury|mid-1950s|Namibia|natural fertiliser|offshore islands|overfishing|Possession|sardine population|seabird excrement|South Africa|southern Namibia|terrestrial predators