INTRODUCTION. xlv 



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, important 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. Dur- 

 ing the night their flight is attended with considerable noise ; 

 the loud cries which we hear, seem to be the marching 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. 



The direction of the winds is of great importance to the 

 migration of birds, not only as an assistance when favorable, 

 but to be avoided when contrary, as the most disastrous of 

 accidents, when they are traversing the ocean. If the breeze 

 suddenly change, the aerial voyagers tack to meet it, and di- 

 verging from their original course, seek the asylum of some 

 land or island, as is the case very frequently with the Quails, 

 who consequently, in their passage across the Mediterranean, 

 at variable times, make a descent in immense numbers on the 

 islands of the Archipelago, where they wait, sometimes for 

 weeks, the arrival of a propitious gale to terminate their jour- 

 ney. And hence we perceive the object of migrating birds, 

 when they alight upon a vessel at sea : it has fallen in their 

 course while seeking refuge from a baffling breeze or over- 

 whelming storm, and after a few hours of rest they wing their 

 way to their previous destination. That Nature has provided 

 ample means to fulfil the wonderful instinct of these feeble but 

 cautious wanderers, appears in every part of their economy. 

 As the period approaches for their general departure, and the 

 chills of autumn are felt, their bodies begin to be loaded with 



