12 



called the " Duiker " in South Africa. It is a well-known 

 enemy of fish everywhere and, in some countries, rewards are 

 offered for the destruction of these pests of the fishermen. 

 Unfortunately, in South Africa, it is the best producer of guano, 

 and thus arises the conflict between the interests of the fisher- 

 men and the farmers, who obtain from Government this 

 valuable fertilizer at a rate less than the open market value. 

 These birds are rigorously protected by law, landing on the 

 islands being prohibited, especially during the breeding season. 

 The fishermen seem to have, therefore good cause for their 

 complaints, as this protection of the chief enemies of fish will 

 naturally be detrimental to the fishing industry. 



That the Duiker is a very expert fisher was very clearly 

 demonstrated on one occasion at the Marine Laboratory at 

 vSt. James. At times the bird seems to be affected by some 

 illness, which causes it to seek the shore, and isolated indi- 

 viduals may be seen perched on some rock where they can be 

 readily approached. On one occasion a Duiker was observed 

 so affected that it could be picked up with hardly any attempt 

 to escape. To discover the nature of its illness if possible, it 

 was brought into the tank-room. Here it remained quite motion- 

 less and seemed to be in a dying condition. As it was thought 

 that it might be revived in its natural element, it was placed in 

 one of the larger tanks, which contained a number of fish, chiefly 

 Dasjes, Harders and Sardines. Immediately the bird seemed 

 to recover, and, to our astonishment, attacked the fish with 

 the greatest vigour. By means of its webbed feet it was able 

 to swim at a rapid rate, turning and changing its course with 

 the greatest facility, apparently by the aid of its wings. The 

 long neck was evidently of great utihty in seizing the fish when 

 within striking distance. It managed to capture several before 

 it could be removed, which was done before much damage 

 could be effected. It may be that such birds are in reality 

 suffering from hunger. (See observation on Duikers dying off, 



P-I3)- 



The Duikers seem capable of concerted action in their 



fishing operations, and I am informed by Mr. Daneel, a member 



of the Fishery Board, that he has seen them surrounding a 



shoal of fish, rounding them up like a flock of sheep, in which 



crowded condition they could be more easily captured. They 



certainly seem to endeavour to drive the fish into shallow 



water, where they can be more easily secured. Thus at Knysna it 



has been observed (Henkel) that the birds form into wide 



circles, drive the fish into shallow water, and cause great 



damage. This is also stated by the fishermen, and has been 



observed on several occasions near the Marine Laboratory at 



