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appreciable effect on migration, which should not be overlooked. 

 There can be no doubt that were it not for the latter, hundreds 

 of thousands of Finches and Larks would have to seek sus- 

 tenance elsewhere. In the same manner individuals of other 

 species, like the Hooded Crow, of which the great body regu- 

 larly migrate, are enabled to find an existence near villages, 

 even in high northern latitudes. SeebohM and Harvie Brown's 

 observations on the Snow Bunting in the Petchora Valley will 

 also illustrate the foregoing remarks (" Siberia in Europe"). 



It is only necessary to imagine the before-mentioned condi- 

 tions prevailing in Northern regions to see how the great migra- 

 tory movements of to-day have been developed, and how birds 

 have acquired that power or sense by means of which they are 

 able to unerringly find their way during the long journeys they 

 now accomplish. 



As has been previously pointed out the movements of birds, 

 will, until the cold became very severe, have been confined to 

 those daily wanderings in search of food before described. But 

 as the spells of frost grew longer and more severe and their 

 extent affected a larger area, so will the distance to be traversed 

 have increased and the intermittent opportunities for return, or 

 attempts to return, to the familiar home have grown less frequent. 

 At the same time the attachment to the old haunts will not have 

 diminished, and on the other hand the power of finding their way 

 and the sense of locality will have constantly become more and 

 more acute owing to the new surroundings requiring their daily 

 exercise. 



It now remains to be seen in what direction these early 

 migrations were likely to have trended. Whether we assume 

 that it was want of light or want of food which first induced 

 birds to temporarily forsake their original home is not of much 

 consequence. Both would be felt most severely in the north. 

 The general tendency, therefore, will be to wander in the 

 opposite direction. The effects of severe frost will be least 

 apparent along sea coasts, the shores of lakes and in river 

 valleys ; indeed at almost all times of the year food is found in 

 such localities in greatest abundance. It seems natural to 

 suppose, therefore, that those individuals and species which 



