542 



THE AMERICAN MUSEUM JOURNAL 



southward to take advantage of the summer 

 there. 



The study of such questions necessitates 

 long residence in a country. During our 

 five and a half years together in the Belgian 

 Congo, Mr. Herbert Lang and I enjoyed a 

 golden opportunity for observations on the 

 periodic movements of the birds, especially 

 since we were always within a few degrees 

 of the equator. Here, as in South Africa, 

 in addition to the Palsearctic migrants, of 

 which about one hundred and fifty kinds 

 visit Africa, there was also a large number of 

 African migrants, some of which breed south 

 of the equator, but the greater number 

 north of it. 



It is worthy of mention that certain of the 

 "northern migrants" are much more com- 

 mon in South Africa, than in the central 

 parts, over which they pass hurriedly. It is 

 surprising, too, how early some of them come 

 south: we have seen white storks back in 

 the Congo on July 18, and it is about a 

 week later than this that the common sand- 

 piper and European swift arrive. The two 

 latter spend by far the greater part of their 

 year in Africa, where they remain until 

 April. 



The greater number of the northern mi- 

 grants arrives in central Africa in September 

 and October, and includes many of the birds 

 most familiar to Europeans, of which we 

 can mention here onlj' a few more: black 

 terns, two species of snipe and many other 

 shore birds, three species of harrier, the honey 

 buzzard, kestrels, osprey, cuckoo, roller, 

 swallow, sand martin, house martin, spotted 

 and pied flycatcher, whinchat, nightingale, 

 redstart, willow warbler, shrikes, wagtails, 

 tree pipit, and oriole. 



We made also a rough classification of 

 migrants in the field. In the Uele District, 

 for example, just on the northeastern border 

 of the forest, this included about fifty-five 

 northern migrants, and thirty-five regular 

 African migrants, not counting birds of 

 irregular occurrence — "partial migrants" — 

 whose numbers are difficult to fix definitely. 

 These were not the same birds that Sclater 

 had reported as leaving South Africa in the 

 winter, for most of them came to this district, 

 just north of the forest, to spend the dry 

 sea.son, which falls approximately in the 

 same months (December to April) as the 

 summer in South Africa. Of all the species 

 cited by Sclater as African or partial mi- 



grants, only ten were noted by us as at all 

 migratory in the Uele. 



This reappearance of certain birds at 

 stated seasons is well known to the black 

 inhabitants of the northeastern Congo, who 

 speak of such birds, in Bangala, the trade 

 dialect, as Ndeke na gala, meaning literally 

 "birds of the dry season." There are a few, 

 however, that come here to spend the rainy 

 season, or parts of it. Great regularity is 

 shown by the African migrants in their 

 arrival and departure. They do not await 

 the annual l)urning of the grass, but generally 

 make their appearance earlier, nor do they 

 all come and go together. Each species has 

 its own calendar. This we were able to 

 verify during the three dry seasons spent at 

 the northern edge of the forest. 



Even such observations as these need 

 confirmation and completion from other 

 regions by other observers; only in this way 

 can definite results be secured. Great 

 assistance can be drawn from books and 

 papers containing records of various species 

 with dates. The notes of von Heuglin on 

 birds of the upper Nile region have proved 

 especially helpful, and the articles in the 

 Ibis by Mr. G. L. Bates, who has lived so 

 many years in the southern Kamerun, are full 

 of valuable information. Mr. Sclater, in 

 South Africa, and other observers in many 

 different parts of the continent, have pub- 

 lished notes of extreme interest, for they 

 enable us to draw definite conclusions from 

 our own experience. The key to the problem 

 is a knowledge of the seasons at which each 

 species is on the move. 



We have now proceeded far enough with 

 this task to be able to point out, in some of 

 these African migrations, where the birds 

 breed, when and how far they go afterward, 

 and in a general way what weather they 

 encounter in the various regions. 



One of the migrants which visits South 

 Africa in summer, but, unlike most of its 

 comrades, does not nest there, is the white- 

 bellied stork (Abdimia abdimii). We found 

 this bird to be one of the few of Sclater's 

 African migrants that is also transient in 

 the upper Congo. There are two seasons 

 when it is seen — often in great flocks, which 

 circle in a huge vortex high overhead. These 

 are: (1) March and April, (2) October and 

 November. Notice how all this fits nicely 

 together. Looking through the literature, 

 we find that storks of this species have been 



