26 
INTRODUCTION. 
We shall not here enter into any detailed description of the man- 
ner in which each species conducts its migration ; but shall con- 
tent ourselves with citing the single remarkable example of the 
motions of the Cranes. Of all migrating birds, these appear to be 
endowed with the greatest share of foresight. They never under- 
take the journey alone : throughout a circle of several miles, they 
appear to communicate the intention of commencing their route. 
Several days previous to their departure, they call upon each other 
by a peculiar cry, as if giving warning to assemble at a cen- 
tral point; the favorable moment being at length arrived, they 
betake themselves to flight, and, in military style, fall into two 
lines, which, uniting at the summit, form an extended angle with 
two equal sides. At the central point of the phalanx, the chief 
takes his station, to whom the whole troop, by their subordination, 
appear to have pledged their obedience. The commander has not 
only the painful task of breaking the path through the air, but he 
has also the charge of watching for the common safety ; to avoid 
the attacks of birds of prey; to range the two lines in a circle, at 
the approach of a tempest, in order to resist with more effect the 
squalls which menace the dispersion of the linear ranks ; and, lastly, 
it is to their leader that the fatigued company look up to appoint 
the most convenient places for nourishment and repose. Still, im- 
portant as is the station and function of the aerial director, its 
existence is but momentary. As soon as he feels sensible of fatigue, 
he cedes his place to the next in the file, and retires himself to its 
extremity. During the night, their flight is attended with con- 
siderable noise ; the loud cries which we hear, seem to be the march- 
ing orders of the chief, answered by the ranks who follow his 
commands. Wild Geese, and several kinds of Ducks, also make 
their aerial voyage nearly in the same manner as the Cranes. The 
loud call of the passing Geese, as they soar securely through the 
higher regions of the air, is familiar to all ; but as an additional 
proof of their sagacity and caution, we may remark, that when 
fogs in the atmosphere render their flight necessarily low, they steal 
along in silence, as if aware of the danger to which their lower path 
now exposes them. 
To assist the efforts of birds, and sustain them through their long 
journeys, it is often necessary to borrow the aid of the winds ; but 
that this element may assist, it is proper that it meet them ; or be 
in the reverse of its aid to the navigator. This observation is so 
far verified, that to succeed in the chase of birds upon the water, it 
