38.2 Mr. A. L. Butler on the 



256. Hydrochelidon leucoptera (Meisner & Schinz). 



257. Hydrochelidon hybrida (Pall.). 



258. Hydrochelidon nigra (Linn.). 



259. Sterna anglica Mont. 



260. Sterna caspia Pall. 



All these Terns are common winter visitors to the White 

 Nile, remaining far into May, by which time they have 

 acquired their full breeding-plumage. 



I have seen Sterna caspia at Khartoum on July 8th. 



261. Rhynchops flaviventris Vieill. 

 a. ? . Khartoum, Sept. 1905. 



The African Skimmer is a common bird on those parts of 

 the Nile where there are sand-banks on which it can rest. In 

 the "sudd" regions of the Upper White Nile I have not 

 seen it. The bird is crepuscular in its habits, and spends 

 most of the day resting in small flocks on the sand-banks. 



Mr. W. G. Percival tells me that he found many nests on 

 some little islands opposite the mouth of the Atbara in April. 

 They were generally deeply scraped hollows, often surrounded 

 with a collection of small shells, and contained two or three 

 eggs. 



262. Larus fuscus Linn. 



A few Lesser Black-backed Gulls are generally to be seen 

 on the White Nile in winter, but they are rare compared 

 with the Terns. 



263. Phojnicopterus sp. inc. 



I have only once or twice seen a Flamingo on the White Nile. 



264. Plectropterus rueppelli Sclat. 



RiippelPs Spur- winged Goose is fairly common on all the 

 Soudan waters south of Khartoum, but nothing like so 

 abundant as the Egyptian Goose. This species and the 

 Comb-Goose are most plentiful in the swamp and "sudd" 

 portions of the country, which the Egyptian Goose cares for 

 least. 



I have never seen so many as in April 1903, when I found 

 thousands collected on a lonely lagoon called Ras Amir, 

 between the Rahad and Dinder Rivers. 



