AN ORNITHOLOGICAL LECTURE. 99 
men recognize the fact that the snipe and woodcock have 
returned, not because the rigorous winter days are wholly 
passed, but because the frost is sufficiently out of the ground 
to allow the worms to come to the surface; and know that 
in warm, springy meadows these birds may often be found 
all through the year. Man no doubt influences the mi- 
gratory habits of birds. To many he offers inducements 
in the shelter, and in the abundance of insects which his 
industry occasions, to linger later in the fall than was their 
wont, and return earlier in the spring. While, on the con- 
trary, the persecution which the shy wild-fowl have received 
has caused them generally to repair to secluded breeding- 
places, far north of their haunts of fifty years ago. But 
the migrations of most birds are somewhat irregular, and 
we have so few reliable data that we can hardly yet deter- 
mine the laws which govern their seasonal movements, 
much less assert the ancient origin of the “ migratory in- 
stinct,”’ so called, or state the varied influences that have 
led to the present powerful habit, and have pointed out 
the routes which the flocks now follow, spring and fall, 
The geologist must aid the zoological student in solving 
these problems. 
The true home of a bird, then, is where it rears its young, 
even though it be not there more than a third of the year, 
