48 



and that the bulk of each species betake them- 

 selves to some warmer climate when they disappear 

 in autumn. There is sufficient evidence on record 

 to establish the migration of birds of this genus; 

 at the same time that, from the inaccurate obser- 

 vation of the witnesses, it is difficult, in most cases, 

 to determine exactly the species alluded to. But 

 while it is pretty certain that the greatest number 

 of swallows migrate, it is not impossible that 

 many individuals of each of the species may be 

 concealed during winter near their summer haunts. 

 Nature may have provided the swallow with this 

 power of accommodating itself to accidental cir- 

 cumstances; and have enabled it, when hatched 

 late, or otherwise prevented from joining the 

 annual emigration, to sleep in security through 

 the season when it could not obtain its proper 

 food abroad ; and to be revived again on the 

 return of warm weather and of food. 



On the other hand, as there exists no proof of 

 the vernal reanimation of torpid swallows, it is 

 possible that their torpidity, perhaps induced 

 merely by cold and hunger, may, unless they be 

 roused by accident before it has gone on too long, 



