NATURAL HISTORY OF SOUTH AFRICA 



dislike to picking up a fish alive even when it is lying 

 helpless on the shore. 



During the Government experimental nettings 

 which I carried out in the Zwartkops tidal river 

 during 191 5-1 6, the gulls hovered round in large 

 numbers and ate up any dead fish which were left 

 on the banks. Sometimes a gull would seize a small 

 fish, and when in mid-air, if the victim showed signs of 

 life, the gull instantly dropped it. On other occasions 

 I have seen mullet leap on to the shore when pursued 

 by a large fish, and watched the gulls swoop down and 

 stand a few yards away and not attempt to seize the 

 fish until its struggles had ceased. 



At Algoa Bay the black-backed gulls {Larus 

 dominicanus) do magnificent scavenging work by 

 eating up all the fish offal cast upon the sand and 

 in the water by fishermen. 



Some years ago the beach to the south of Port 

 Elizabeth was thickly strewn with dead fish, and the 

 gulls gathered from afar and ate them up. The 

 denizens of the ocean are subject to attacks of epidemics 

 of diseases, as are their more evolved kindred of terra 

 firma. Gulls, by eating the bodies of those that die 

 of disease, are largely instrumental in keeping fish 

 diseases in check. Gulls are therefore guardians of 

 the health of the ocean's population, as well as acting as 

 scavengers of the seashores and dirty, insanitary villages 

 adjacent to the seashore. When pressed for food, 

 gulls penetrate inland for miles in search of grass- 

 hoppers, locusts, and caterpillars. 



Black-backed gulls, which I kept in captivity for 

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