DO SWALLOWS HIBERNATE? 165 



it is impossible to believe that, however brilliant the 

 moonlight may be, any bird could distinguish, at the ele- 

 vation of a mile or more, the limited area of its former 

 summer haunts, the particular thicket in which it nested 

 the foregoing summer ; or, in the case of swallows, the 

 little bluff wherein a colony had had their subterranean 

 summer homes. The most that can be claimed is their 

 recognition of the particular river valley wherein they 

 have been accustomed to spend the summer. Granting 

 this, if they migrated at night, then it is early in the 

 morning after their arrival that we should expect to see 

 them resting in scattered numbers after their journey ; 

 and when thus wearied from a protracted flight, and 

 damped with the dews that have bathed surrounding 

 Nature, they might well present the appearance of hav- 

 ing arisen from the waters beneath, rather than fallen 

 from the clouds above. 



Continuing our consideration of these bank-swallows, 

 let us now pass to the time of their annual disappearance, 

 late in autumn, or at the onset of winter. Two condi- 

 tions cause the change of habitation, or, at least, the dis- 

 appearance from their summer haunts a much lower 

 temperature, and absence of insects, their only food. 

 Now, severe frosts often occur in October, or they may 

 be delayed until November, but this alone does not de- 

 cide the movements of the swallows ; for often they have 

 wholly disappeared before October, and then a year may 

 pass, with flitting swallows skimming o'er the lea, un- 

 daunted by the chill November fogs. The supposed 

 regularity of their comings and goings is not applicable 

 to their New Jersey haunts, however it may be in more 

 northern localities. 



What, therefore, I have seen of their movements in 

 autumn that has possible bearing upon alleged hiberna- 



