Migration of Birds in Africa 



Bv JAMES P. CHAPIN 



THE many fascinating volumes that 

 have been written on the travels of 

 birds deal especially with those of the 

 North Temperate and Arctic regions, 

 and these migrations are beyond a doubt the 

 most striking; but it is well known that 

 certain species in the Southern Hemisphere 

 have similar instincts. In the Argentine, 

 in South Africa, and in Australia there are 

 land birds that withdraw to the northward 

 during the cold season; and some of the 

 oceanic birds nesting on the islands of the 

 southern seas migrate in the same direction. 

 One among them, Wilson's petrel, is common 

 even in our northerly latitude in July. 

 Within the tropics, however, the compara- 

 tively uniform temperature throughout the 

 year would seem to favor the development of 

 sedentary habits, and this is generally agreed 

 to be the case. 



Nevertheless there is some change of season 

 even close to the equator, where the continued 

 heat and damp trade winds produce a moist 

 and sultry zone known as the "equatorial 

 calm belt, " the "doldrums" of sailors. As a 

 result of the inclination of the earth's axis, 

 this belt is farthest north in July, and farthest 

 south in January, hence at latitudes of five 

 to twenty degrees there is a regular alterna- 

 tion of rainy and dry seasons of four to seven 

 months each, and nearer the equator it is apt 

 to rain throughout the year. 



To these conditions West Africa owes its 

 great rain forest, covering most of the shores 

 of the Gulf of Guinea and the middle of the 

 Congo basin. This forest is a factor of 

 prime importance in the distribution of 

 African birds; and the traveler in tropical 

 Africa, almost without reflection, classifies 

 them as water birds, forest birds, and plains 

 or savannah birds. There are, to be sure, 

 also mountain birds, but African mountain 

 ranges are never long and high enough to act 

 as effectual barriers. 



To a savannah bird, on the other hand, 

 this great forest, hundreds of miles wide, is a 

 real obstruction, while the true bird of the 

 forest seldom ventures far from its shade, 

 and may even show a strong dislike for 

 second growth. These forest birds, enjoying 

 a perpetual rainy season, certainly have 



little reason to migrate, and indeed seldom 

 do so. It is among the birds of "bushveldt" 

 and plains, where drought reigns for part 

 of the year, that we find the migratory 

 instinct better developed. Some of these 

 even cross the wide forest region on their 

 journeys. 



While considering the conditions in the 

 equatorial region, we must not lose sight of 

 those in South Africa. These conditions 

 are admirably summed up in Mr. W. L. 

 Sclater's paper on The Migration of Birds 

 in South Africa, read in 1905 before the 

 British Association in Johannesburg. Of 

 the 814 species known from that region, 

 76 are migrants from Europe and Asia, 21 

 are "African migrants," coming in summer 

 to South Africa, where most of them nest, 

 and 49 others — -"partial migrants" — are 

 somewhat migratory, but are fairly numer- 

 ous at all times of year in that territory. 

 The 36 "island breeders" — all sea birds 

 nesting on oceanic islands — are found on the 

 South African coasts in winter. 



Mr. Sclater's object was to stimulate the 

 interest of South Africans, and to secure 

 further information. Scores of white storks, 

 banded in Germany, have been found in 

 South Africa, where a few of this species 

 sometimes remain throughout the year, but 

 do not breed. The European bee eater does 

 actually nest occasionally in South Africa, 

 and the purple and gray herons, of the same 

 species as in Europe, do so regularly. 



Still more needed were observations from 

 farther north, in central Africa, to show where 

 the South African migrants "wintered." 

 We find this already stated in 1892, in Charles 

 Dixon's volume on The Migration of Birds. 

 The fact that certain northern species, for 

 example: Bonaparte's sandpiper, the eastern 

 golden plover, the turnstone, the eared grebe, 

 and the quail, were supposed to breed also in 

 the Southern Hemisphere, led him to postu- 

 late a "neutral zone," not only in central 

 Africa, but probably in Brazil and the Malay 

 Archipelago as well, where certain species 

 would be found throughout the year, yet 

 never breeding; for some would go north to 

 nest during the northern summer, and the 

 remainder at the opposite season repair to the 



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