24 INTRODUCTION. 



(as Mr. Bullock * witnessed in a voyage near to Vera Cruz late in 

 autumn,) the famished travellers familiarly crowd the decks of the 

 vessel, in the hope of obtaining rest and a scanty meal, preparatory 

 to the conclusion of their unpropitious flight. 



Superficial observers, substituting their own ideas for facts, are 

 ready to conclude, and frequently assert, that the old and young, 

 before leaving, assemble together for mutual departure ; this may be 

 true, in many instances, but in as many more a diiferent arrange- 

 ment obtains. The young, often instinctively vagrant, herd together 

 in separate flocks previous to their departure, and guided alone by 

 tlie innate monition of nature, seek neither the aid nor the company 

 of the old ; consequently in some countries flocks of young of par- 

 ticular species are alone observed, and in others, far distant, we 

 recognise the old. From parental aid, the juvenile company have 

 obtained all that nature intended to bestov*^, existence and education ; 

 and they are now thrown upon the world among their numerous com- 

 panions, with no other necessary guide than self-preserving instinct. 

 In Europe it appears that these bands of the young always affect 

 even a warmer climate than the old ; the aeration of their blood 

 not being yet complete, they are more sensible to the rigors of cold. 

 The season of the year has also its effect on the movements of 

 birds; thus certain species proceed to their northern destination 

 more to the eastward in the spring ; and return from it to the south- 

 westward in autumn. 



The habitudes and extent of the migrations of birds admit of con- 

 siderable variety. Some only fly before the inundating storms of 

 winter, and return with the first dawn of spring ; these do not leave 

 tlie continent, and only migrate in quest of food, when it actually 

 beo-ms to fail. Among these may be named our common Song 

 Sparrow, Chipping Sparrow, Blue-bird, Robin, Pewee, Cedar-bird, 

 Blackbird, Meadow Lark, and many more. Others pass into warmer 

 climates in the autumn, after rearing their young. Some are so 

 given to wandering, that their choice of a country is only regulated 

 by the resources which it offers for subsistence ; such are the Pigeons, 

 Herons of several kinds. Snipes, Wild Geese and Ducks, the wan- 

 dering Albatros, and Waxen Chatterer. 



The greater number of birds travel in the night ; some species, 

 however, proceed only by day, as the diurnal birds of prey. Crows, 

 Pies, Wrens, Creepers, Cross-bills, Larks, Blue-birds, Swallows, and 



* Travels in Mexico. 



