LINES OF MIGRATORY FLIGHT 155 



In the Cape region of South Africa W. L. Sclater 

 has recorded seventy-six migrant species from 

 Europe and Asia that come for the period of the 

 northern winter; while J. P. Chapin, working 

 mainly in the forest belt of equatorial Africa, has 

 recorded approximately fifty visitors from the Palae- 

 arctic region. On the face of it one might suppose 

 that the great desert of the Sahara would interpose a 

 barrier to flight as perilous to cross as that of some 

 great sea, but apparently this is hardly true since, 

 though bird life is scant in areas of shifting sands, 

 zoological exploration of recent years has yielded a 

 varied avifauna in many districts in the Sahara. 

 Hartert has recorded 24 or more Northern Hemi- 

 sphere migrants in Air in the central Sahara, where 

 they were associated with many obviously tropical 

 species; and there are broad areas where desert 

 mountains and semi-arid valleys offer favorable 

 conditions. To the eastward the Nile Valley and the 

 eastern coast-line offer ready fly lines, which lead as 

 far south as the bird may care to go. The valley of 

 the Nile in particular is favored by multitudes of 

 shore-birds, cranes, ducks, and other fowl that nest 

 in northern Europe and Siberia. 



The northern migrants that reach southern Africa 

 arrive in October and leave for the north in March 

 and April. Among them are included such well- 

 known European birds as the golden oriole, four 



