MIGRATION OF SHORE-BIRDS 115 



fitted in general for a long flight than in the autumn, fewer 

 individuals succumb to storms and exhaustion. Thus we do 

 not hear so often in spring as in autumn of the finding 

 of some species of migratory bird which has fallen exhausted 

 to die. Birds migrate at night as well as day ; thus, if a 

 number pass over the observer without giving any call notes at 

 night, nothing can be recorded of them if the night is dark. 

 It often happens that spring migrants arrive at their breeding 

 haunts some time during the night, and the first that is noted 

 of them is that they are seen there by the observer on the 

 following morning. This is particularly the case with our 

 common summer visitor, the corncrake, or landrail. One 

 seldom sees this bird arrive. He is, however, frequently shot 

 on our shores at the time of his departure in the autumn. 



The distances traversed by some migratory birds are cer- 

 tainly beyond the conception of man, as far as how the journey 

 is so accurately performed. We have birds visiting our islands 

 on passage to and from the north every year. These creatures 

 journey a distance nearly equal to that from the Equator to 

 the Pole. Birds as a rule perform their spring migration 

 much more quickly and with more punctuality than they do 

 their autumnal. Many very sufficient reasons are advanced in 

 support of this statement. In the case of tardy southward 

 movements the birds may be waiting for the young to attain 

 full growth and flight, etc. ; but it must not be supposed that 

 this in all cases holds good, for swallows have been known to 

 leave their young in the nest to perish rather than delay their 

 southward movement. In spring the dates of arrival of 

 familiar migrants can now, after our somewhat lengthy ex- 

 perience and observations, be fixed with fair accuracy, and it 

 is singular to find, despite the weather, that these birds arrive 

 annually within a few days of their time. For seven years, 

 during the first few days of May, I visited a certain grassy 

 common where moor-dotterels halted for a brief period on 



