I MIGRATION ny 
from Greece to Iceland. What is left of Arabia and Africa, after 
taking off the above portions, with the addition of Madagascar 
and the Mascarene Islands, is the Athiopian Region; and all the 
rest of continental Asia, with the islands not included in the 
Australian Region, becomes the Jndian, or, as it has lately been 
ealled, the Oriental. It would be quite impossible to enumerate 
here the various Sub-regions and Provinces into which~ these 
several Regions may be divided. The views of Mr. Wallace are 
set forth at leneth in his excellent work, those of Mr. Sclater in 
The Ibis for 1891, pp. 514-557, and those of Professor Newton 
in lis Dictionary of Birds. Many writers would assign to Mada- 
gascar a higher rank than that of a Sub-region. 
Migration —Few peculiarities of Birds have excited more 
general interest than their seasonal Migration, which im many 
species 18 so marked as to have been observed from very remote 
times; and it is probable that nearly all species are subject to 
periodical movements of varying extent. These movements are 
greatest in the Birds which have their breeding quarters in the 
northern parts of the Northern Hemisphere; and, with some 
exceptions, it may be said that the more northerly is the range 
of a species the more extensive are its migratory wanderings. 
In the Southern Hemisphere the facts known are as yet 
insufficient to allow of safe deductions. Absence of a food- 
supply in winter is alone enough to account for migration in the 
above cases, and the return from the south in spring is_ prob- 
ably due to the desire of Birds to reoccupy their old haunts, or 
those in which they have been bred. But just as there are some 
‘species which habitually breed within the Arctic Circle and winter 
in the Tropics, there are others which may not go so far in either 
direction, and yet have their movements governed by exactly the 
same principle, with the result that in a temperate zone we 
have Birds coming from the north to winter with us, while 
others, arriving from the south in spring, spend the summer 
here, and depart towards autumn. Others again, the true “ Birds 
of Passage,” arriving like the last in spring, make little or no 
stay, but pass onward to more northerly lands, and re-appear for 
as short a time in autumn on their return journey southwards. 
Moreover, observation shews that, in most parts of the temperate 
zone, there are many Birds which, though resident as species, are 
migratory as individuals—that is to say, that while examples of 
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