MIGRATION OF BIRDS IN AFRICA 



543 



discovered nesting only north of the forest 

 belt, from northern Nigeria to Al)yssinia, 

 and Aden in southern Arabia, southward to 

 British East Africa. In this area they are 

 found from March to September, building 

 nests in colonies on trees or even on roofs, 

 like the white stork of Europe. 



Then comes the great migration already 

 noticed, which obliges numbers of them to 

 cross the Congo forest, where they can find 

 food only in the scattered clearings made by 

 man. Others avoid the forest by going 

 through East Africa, and many reach 

 Cape Colon}', their wanderings thus tak- 

 ing them farther south of the equator than 

 their breeding range lies north of it. They 

 nest, then, during the rainy season to the 

 north, and enjoy the rainy months, or sum- 

 mer, in southern Africa. 



One of the common birds to invade the 

 Congo every year in late October, and which 

 I took at first for a visitor from Asia, is the 

 white-necked bee eater (Aerops albicollis). 

 Abundant, not only in the more open dis- 

 tricts but also about clearings in the forest, 

 these bee eaters often gather in large noisy 

 flocks, especially toward evening. At this 

 season they even extend out into the savan- 

 nah country south of the forest, but do not 

 breed. 



Bates reports that they spend the months 

 from November to April in the Kamerun, 

 and there are records at this season from as 

 far west as Senegal. In the northeastern 

 Congo they remain regularly till early June, 

 and I have known them to stay in the Uele 

 till as late as June 15. 



The breeding range of the species, to which 

 they now betake themselves, extends from 

 the Sudan to Abyssinia and southern Ara- 

 bia, southward in Africa to Uganda. To 

 this territory they are confined through 

 most of the rainy season — that is from July 

 to Septemljer — after which they again 

 return southward, and many cross the 

 equator. The northern limit of the breeding 

 range is close to latitude 20° N., the southern 

 edge of the "winter" range about lati- 

 tude 10° S. Those which stay in the forested 

 territory do not suffer from drought, and 

 south of this they find the rainy season in 

 progress. 



The white-necked bee eater is not held 

 back by the Congo forest; but the greater 

 number of the Sudanese birds which come 

 south to the Uele for the dry season do not 



usually go beyond the border of the savannah. 

 It is often said that birds in the tropics prefer 

 to breed in the rainy season, but this rule has 

 many exceptions. Among these birds visiting 

 the ITele in the dry season, a number nest 

 regularly — • for example, a large bustard {Otis 

 denhami), a nocturnal plover (Oedicnemus 

 senegalenis) , a wattled lapwing {Lobivanellus 

 senegaUus), a buzzard (Buleo auguralis), a 

 gray hornbill (Lophoceros nasutus), a hoopoe 

 (l^pupa senegalensis) a beautiful kingfisher 

 {Halcyon senegalensis), the standard-winged 

 nightjar {Macrodipteryx macrodiplerus) and 

 a sunbird {Hedydipna platura). 



Others do not nest while in the Uele. As 

 an example of this we may take the red- 

 winged buzzard {Butastur rufipemiis), a bird 

 of prey feeding mainly on grasshoppers — 

 often captured on the wing before an advanc- 

 ing bush fire, which attracts many other birds, 

 such as kites, swallows, and beautiful rosy 

 bee eaters. This buzzard is common in the 

 Uele from November to the end of March, 

 and has been collected at the same season as 

 far west as northern Kamerun. To lareed, 

 however, it goes northward in April to the 

 White Nile, as far as Khartoum, where Mr. 

 A. L. Butler has observed that it disappears 

 in October. 



So far the migrants considered have all 

 been birds that nest north of the equator. 

 One of the best instances of a species which 

 breeds south of the equator and migrates 

 north to the Sudan is the pennant-winged 

 nightjar {Cosmetornis vexillarius) . The male 

 is a striking bird with long narrow plumes 

 waving out behind its broad wings, and we 

 found that both males and females cross the 

 forest belt each year in February and March, 

 after which they become common in the 

 savannah country to the northward. 



In July and August however, they take 

 their departure again, without having laid 

 eggs, and at this season they are again to be 

 seen at dusk about villages in the forest, or 

 aroused from their slumbers in the daytime, 

 on the ground in clearings or open swampy 

 spots. They are on their way south, for 

 they breed in September, October, and 

 November, from Angola and Lake Tangan- 

 yika to Damaraland and the Transvaal. 

 Many of Sclater's South African migrants 

 may be compared with this bird, though 

 they range for the most part, while breeding, 

 farther south, and do not travel so far 

 northward. 



