322 
COLUMBA MIGRATOR I A. 
been observed, that the pigeons, when passing over a 
steril part of the country, keep high in the air ; but 
if, on the contrary, the land is richly covered with food, 
they will fly low, in order to discover the places most 
abundant in food. The form of these migrating bodies 
is an elongated oval, steered by a long, well-plumed 
tail, furnished with well set, and very muscular wings, 
for the size of the individual. If a single bird is seen 
gliding through the woods, and close by, it passes as 
if by magic; and, on trying to see it again, the eye 
searches in vain — the bird is gone. 
The multitudes of these birds almost pass belief. In 
the autumn of 1813, Audubon left his house at Hen- 
derson, on the banks of the Ohio, on his way to 
Louisville. Having met the pigeons flying from N.E. 
to S.W. in greater numbers than usual, he felt an 
inclination to enumerate the flocks that would pass 
within the reach of the eye in the course of one hour. 
He dismounted, and, seating himself on a small emi- 
nence, began to mark, in his pocket-book, a dot for every 
flock which passed. Finding, however, that this was 
scarcely possible, and feeling unable to record the flocks, 
as they constantly increased, he rose, and, counting 
the dots already put down, found that 163 had been 
made in twenty-one minutes. He travelled on, and 
still met more the farther he went. The air was 
literally filled with pigeons ; the light of noon-day 
became dim, as during an eclipse. Whilst waiting for 
dinner at the Sun, Audubon saw, at his leisure, immense 
legions still going by, and he says, “ But I cannot 
describe to you the extreme beauty of their aerial 
evolutions, when a hawk chanced to press upon the 
rear of a flock. At once, like a torrent, and with a 
noise like thunder, they rushed into a compact mass, 
feathers of the tail close together, and closing the wings, they thereby 
render the action of the air predominant on the posterior part of 
the body, which directs the anterior part downwards, and delivers 
it over entirely to the influence of gravity. 
The tail can strengthen the action of the wing, by directing 
itself towards it. 
