INTRODUCTION. XXXvii 



sive voyages, are sedulously employed ; and hence, at certain 

 seasons, when they are usually in motion, we find their arrival 

 or departure accelerated by a favorable direction of the winds. 

 That birds also should be able to derive advantage in their 

 journeys from the acuteness of their vision, is not more wonder- 

 ful than the capacity of a dog to discover the path of his 

 master, for many miles in succession, by the mere scent of his 

 steps. It is said, indeed, in corroboration of this conjecture, 

 that the Passenger, or Carrying Pigeon, is not certain to return 

 to the place from whence it is brought, unless it be conveyed 

 in an open wicker basket admitting a view of the passing 

 scenery. Many of our birds, however, follow instinctively the 

 great valleys and river-courses, which tend towards their 

 southern or warmer destination ; thus the great valleys of 

 the Connecticut, the Hudson, the Delaware, the Susquehanna, 

 the Santee, and more particularly the vast Mississippi, are often, 

 in part, the leading routes of our migrating birds. But. in fact, 

 mysterious as is the voyage and departure of our birds, like 

 those of all other countries where they remove at all, the des- 

 tination of many is rendered certain, as soon as we visit the 

 southern parts of the Union, or the adjoining countries of Mex- 

 ico, to which they have retired for the winter ; for now, where 

 they were nearly or wholly unknown in summer, they throng 

 by thousands, and flit before our path like the showering leaves 

 of autumn. It is curious to observe the pertinacity of this 

 adventurous instinct in those more truly and exclusively insec- 

 tivorous species which wholly leave us for the mild and genial 

 regions of the tropics. Many penetrate to their destination 

 through Mexico overland ; to these the whole journey is 

 merely an amusing and varied feast. But to a much smaller 

 number, who keep too far toward the sea-coast, and enter the 

 ocean-bound peninsula of Florida, a more arduous aerial voy- 

 age is presented ; the wide ocean must be crossed, by the 

 young and inexperienced as well as the old and venturous, 

 before they arrive either at the tropical continent or its scat- 

 tered islands. When the wind proves propitious, however, 

 our little voyagers wing their unerring way like prosperous 



