1920.] Birds of the Cancnij Islands. 565 



Sparrow, (^haffinches (of the F. ccelebs groiip), Linnet, 

 Corn Bunting, Titmice, etc. The list could be increased of 

 those residents which have probably never passed south 

 beyond the latitude of the Canary Archipelago. 



The remarkable fact that we have in the Canaries a Black 

 Oystercatcher may possibly be put down to the same cause. 

 Its nearest ally is an inhaljitant of South Africa, but does 

 not now extend farther north than Damaraland on the West 

 Coast. Either the bird has gradually pushed farther and 

 farther north until its present home was reached, or it once 

 lived commonly in these latitudes and for some reason has 

 been slowly pushed soutliwai-ds down the coast of West 

 Africa, leaving no trace save the fast disapj)earing subspecies ; 

 for it has become markedly difllerentiated, isolated in the 

 desert islands of the eastern Canary group. I lean to the 

 foiiner explanation of its presence there, otherwise surely 

 we should find other races in the islands or on the mainland 

 between the Canaries and the habitat of its nearest ally. 

 The lessons to be learnt from studying this bird alone are 

 typical of what may be gleaned when the avifauna of a 

 whole Archipelago is under examination. 



Only migration from the continent to the islands and 

 vice versa has been discussed here. That a certain amount 

 of local migration takes place in the islands themselves (not 

 betiveen the islands) seems evident, caused by local weather 

 conditions or even influenced by human agency. 



Meade-Waldo (Ibis, 1889, p. 2) speaks of the iniiuigration 

 of the Blackbird {Turdus merula cahrerce) in Tenerife from 

 the lowlands to the highlands of that island. C*uriouslv 

 enough they " swarmetl in the high forests during the 

 winter," when one would imagine they wonld seek the 

 warmer zone of the coast. The same observer notes that 

 large numbers of Canaries ascend to the high mountiiin 

 woods to breed, going up about the end of April. A[)parently 

 they returned to the lowland valleys after breeding. 



Von Thanner remarks that it is quite the exception to 

 find a Hoopoe in the higher districts of Gran Canaria and 

 Tenerife during the winter, though he has found them 



