MIGRATION OF SHORE-BIRDS r13 
fieldfare. It may be that the individual fieldfares which in 
hard winters become victims of the rigours of the weather here, 
have reached their southern limit of migration, and that their 
knowledge or power of further progress is also limited. On 
the other hand, some birds may be said to have exceeded the 
range of necessary migration by accomplishing enormous and 
incredible distances. I would here mention the whimbrel, 
curlew-sandpiper, and little stint. There is no absolute need 
for these species to journey so far. 
For the benefit of those who have not closely studied the 
migration of birds, I will mention a very generally accepted 
theory on the subject. This migration of birds is a mystery 
which may ever remain unsolved, and, beyond stating that it 
is undoubtedly an evolution of a habit which has with the 
hand of time become a natural instinct, I leave this point to 
others. Furthermore, it is thought by those persons who have 
scientifically studied birds that a common desire or custom to 
return to where they were bred is more or less evident, should 
unavoidable circumstances have been instrumental in driving 
them from their nesting-ground. In all creatures some power 
instils a longing to return to the land of birth, provided a 
return is practicable. This is but common natural history. 
Supposing, as we are led to do, that somewhere near the 
North Pole was the first home of birds, and that through 
the ages, with changing meteorological conditions transform- 
ing the climatic status, the birds each year have been com- 
pelled to seek lands anew, with the advent of a possible chance 
to return to their old homes they would, witha natural impulse, 
rush thither. In this manner, in the course of time (how long 
it would be difficult to estimate), this wonderful migration has 
been brought about. 
In the southern hemisphere bird migration is totally dis- 
similar to that of the northern, and what little is noticed is said 
to be entirely of local origin. When speaking of the south- 
H 
