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Our birds which build protected nests, or which are able to protect 
their nests are not migratory birds as a rule. I know of but one clear 
exception, the sapsucker. Our birds which build unsafe nests or which can- 
not protect them are migratory birds asa rule. I know of no exception that 
is clear. The Phoebe arrives when its food is scarce, and it leaves a land of 
plenty, a land of insects; food cannot be the attraction. That climate is 
not the compelling cause is shown by the fact that many birds arrive when 
the climate is very severe; it even kills thousands of them sometimes. 
That birds are indigenous in the north; that they are migrating in 
the fall instead of the spring; that in the spring they are just going to 
their preglacial home; and that nostalgia is the real cause requires us to 
believe that birds have a way of preserving a record of their lost Atlantis 
that we do not possess, and may be dismissed as wholly psychological. 
The salmon goes a thousand miles up the Columbia to spawn; the eel 
question has at last been solved; it goes to the deep sea to spawn. Sea- 
birds go to isolated rocks for the same purpose. It is the conclusion of 
this paper—there being no shred of evidence against it, and many weighty 
reasons for it—that our migratory birds go north for safety in nesting. 
