Great white pelicans on Dyer Island , in the Western Cape region of South Africa , were culled during the 19th century .
Pelicans ' predation of the eggs and chicks of guano - producing seabirds was seen to threaten the livelihood of the guano collectors .
Great white pelicans on Dyer Island , in the Western Cape region of South Africa , were culled during the 19th century because their predation of the eggs and chicks of guano - producing seabirds was seen to threaten the livelihood of the guano collectors .