388 Lieiit.-Col. K. Meincrtzhagen on [Ibis, 



colonies which breed in Soutli Africa are resident com- 

 munities who have dropped the migratory habit as redundant 

 to their life. 



Again, we find the Sandpiper {Totanus hypoleucus) nesting 

 in tropical East Africa (Van Someren), and the writer 

 observed the young of this species with their parents on the 

 Kajiado River near Nairobi in 1915. The Pratincole is 

 reported to have bred in a colony near Durban in November 

 1917 (Ibis, 1908, p. .385), GeoUVoy's Sand- Plover is sus- 

 pected of breeding in Somaliland (Archer) and the Swallow 

 [Hirundo r. rusticn) in Uganda and on Kilimanjaro. 



It is iield that these cases of expansion of the breeding- 

 range are directly attributable to migration, as they all 

 occur among species in which the migratoi-y instinct is 

 strongly developed. Whether or no these instances are 

 oases of incii)ient isolation remains to be seen. If this is 

 the case, we shall get dift'erentiation, as in the case of Corvus 

 comix, the Hooded Crow, which has two communities, in 

 Egvpt and on the Persian Gulf, both of which have lost the 

 miffratorv habit, and one of which has assumed considerable 

 dirterentiation. 



It has been stated (Eagle Clarlj|, ' Migration of Birds,^ i. 

 pp. 15-17) that southern tropical regions are not suited as a 

 nurserv for the hardy nortliern birds, and if breeding were 

 attempted in such regions the species would become extinct. 



Facts do not entirely support this view, though doubtless 

 it is true as a broad principle. We have already referred 

 to the Hooded Crow, an essentially hardy northern species 

 and one of the few birds remaining in Arctic Norway in 

 winter, as breeding under one form [Corviis capeUanus) 

 on the shores of the Persian Gulf, one of the hottest parts 

 of the world and eelijising the heat of any part of tropical 

 Africa, while yet another unditferentiated form is resident 

 in Egypt and northern Sinai. We find a Swallow {I/irundo 

 savi(j>ni) breeding in Egypt, various forms of the White Owl 

 and Kestrel throughout the tropics of Asia and Africa, and 

 other birds such as Saxicohi torquata, the Stonechat, with 

 o-eographical races equally at home from the xVretic Regions 

 to Cape Town. 



