154 THE MIGRATIONS OF BIRDS 



The migrations of birds in Africa are comparable 

 to those recorded for South America, though, as on 

 that continent, information available from the tropi- 

 cal area is meagre, since ornithologists interested in 

 the subject have seldom been resident for sufficient 

 time to make prolonged observations. As a winter 

 resort for migrants from the Northern Hemisphere, 

 Africa is more popular than South America, prob- 

 ably because of the comparative ease with which it 

 is reached by cautious wayfarers. Spain, Italy, and 

 near-by islands, and Arabia, offer passageways on a 

 broad front for birds that do not care to attempt 

 directly a crossing of the comparatively narrow 

 width of the Mediterranean. If blown aside by 

 storm, migrants have fair chance of a landing some- 

 where on the broad land area of either the northern 

 or southern continent, so that the dangers of crossing 

 are little more than those incurred in flight over 

 land. The physical barriers imposed against mi- 

 grants are thus more favorable than in the New 

 World, where the Gulf of Mexico and the Caribbean 

 Sea extend at an angle, with a narrow line of islands, 

 separated by considerable distances in some cases, 

 forming the only barrier from the open sea on the 

 east. It has been said that more migrants cross the 

 Mediterranean Sea than any other sea in the world 

 though whether more pass than fly across the Carib- 

 bean and the Gulf of Mexico combined is perhaps 

 open to question. 



