NATURAL HISTORY OF SOUTH AFRICA 



flocks when there are shoals of hsh about. They descend 

 perpendicularly from great heights on to their prey. Their 

 food consists entirely of fish, of which they destroy enormous 

 numbers. Their cry is harsh and raucous. This they emit 

 both when flying and when on their nest. About October 

 they congregate in large numbers on the breeding islands 

 round the coasts. Bird Island, near Port Elizabeth, forms 

 one of these breeding islands. Here they nest in countless 

 numbers side by side, almost touching one another. The 

 nest consists of a small depression in the sand, which is soon 

 surrounded by a ridge of dry excrement. One egg only is laid. 

 When newly laid it is pure white in colour, due to a chalky 

 layer which hides the underlying pale blue of the egg. They 

 measure approximately 3.12 by 2.0, and are oval in shape. 

 The bird sits very close, covering the egg with its feet and 

 breast. It is a wonderful sight to see this huge mass of birds 

 all squabbling or signalling to their mates. 



The young when hatched are covered with white down. 

 When able to fly they depart from the island, not returning until 

 they are adult. These birds, together with the duiker, are the 

 chief contributors to the guano deposits. This guano is 

 collected from the nesting sites after the birds have departed, 

 and forms a very valuable asset to the country. 



Hammerkop, or Paddevanger (Scopus lunbretta). 



(Vol. II., p. 205.) 



Description. — Sepia-brown above, with here and there a 

 slight purplish gloss. Crest on nape of neck about 3 in. long. 

 Tail similar to back and also glossy but paler, with a broad, 

 darker subterminal band and six or seven narrow transverse 

 bands above. Below brown, paler than back. Under tail 

 coverts barred. Iris dark brown. Bill and legs black. 



Lengthy 22.25 5 ^^'^^5 ^2.75 ; tail, 6.70. 

 Female resembles male. 



The nestlings are covered with white down ; rather greyish 

 on the back. 



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