114 THE COMPLETE WILDFOWLER 
ward movements of birds we cannot easily leave out the 
northward ; but in making observations on this subject it is 
practically necessary to compare the spring and autumn migra- 
tions, though here it is intended to deal chiefly with those of 
the autumn months. The latter are for many reasons much 
more easily and accurately observable than those of the spring. 
In the autumn there is a larger number of birds on the move, 
and many are immature, and have, of course, never before 
braved a lengthy flight. In the spring, however, every north- 
ward-journeying bird is one which has proved victor in a long 
flight, and, moreover, is an individual which has taken care of 
itself and survived the non-breeding season. ‘Thus it is that 
with many far-journeying species fewer are observed in the 
spring than in the autumn. Few mistakes are made by spring 
migrant birds compared with autumn migrants, as far as the 
right direction of their course is concerned. Nearly every 
autumn we have proof of this in the occurrence of some 
American species crossing the Atlantic ocean to our islands, 
such, for instance, as the pectoral sandpiper. Although in 
spring we seldom hear of mistakes made in the line of flight of 
migrants, yet we are told by a late learned ornithologist that 
he observed in high northern latitudes geese flying southwards 
when they should have been going north, and it was his 
opinion that in their eagerness to reach their breeding homes 
they had ‘‘ overshot the mark,” and were obliged to turn back, 
no doubt on account of their homes being frozen up. Many 
such instances of what might be termed fairly reasonable proof 
of errors made by migratory birds might be cited, but space 
will not allow. 
All migratory birds are subject to mistakes of some kind or 
other, which at times prove very disastrous to large numbers 
of them ; but what I wish to impress is that the spring migra- 
tion of birds seems to take place without such conspicuous 
error. Likewise, the spring migrants being physically better 
