INTRODUCTION. 
23 
by atmospheric phenomena alone ; and hence we find that their ap- 
pearance is frequently a concomitant of the approaching season, 
and the wild Petrel of the ocean is not the only harbinger of storm 
and coming change. The currents of the air, in those which make 
extensive 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 wonderful, than the ca- 
pacity 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 Susquehannah., the 
Santee, and more particularly the vast Mississippi, are often, in 
part, the leading routes of our migrating birds. But, in fact, mys- 
terious as is the voyage and departure of our birds, like those of 
all other countries where they remove at all, the destination of many 
is rendered certain, as soon as we visit the southern parts of the 
Union, or the adjoining countries of Mexico, 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 insectivorous species, which wholly leave us for the 
mild and genial regions of the tropics. Many penetrate to their 
destination through Mexico over land ; to these the whole journey 
is merely an amusing and varied feast ; but to a much smaller num- 
ber, who keep too far toward the sea-coast, and enter the ocean-bound 
peninsula of Florida, a more arduous aerial voyage 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 scattered islands. When the wind proves 
propitious, however, our little voyagers wing their unerring way 
like prosperous fairies; but, baffled by storms and contrary gales, 
they often suffer from want, and at times, like the Quails, become 
victims to the devouring waves. On such unfortunate occasions, 
