ON THE MIGRATION OF SWALLOWS. 2J5 



Britain aud Ireland. Indeed, considering the great strength 

 of wing, and velocity, ol' the swallow tribe, it must have 

 been a tremendous gule that could drive them off the land: 

 byt, the previous weather was nothing boisterous, and cap- 

 tain Tnomson experienced little more than a steady breeze. 



4. The great number of these birds is another argument 

 against the supposition of their having been carried to sea 

 by a storm. Such instances in solitary birds of weak wing 

 are not uncommon. I once caught a golden crested wren 

 {motacUla re^ulns, Lin.) iu the shrouds of a vessel, when 

 driven off the coast of Scotland by a sudden tempest ; but 

 instances of iai ge flocks of birds, so strong and active as 

 the swallow tribe, becoming the sport of the winds, are 

 certa lily very uncommon, even when the weather has been 

 tempestuous. 



5. Captain Thomson expressly mentions both swallows There were at 



and martins ; and he stated to 4ne, that they differed in ''r^^'^ ^^'° *P*' 

 • r¥ » 1 • p .1 cies. 



size. Hence, there were, at least, two species or swallows 



observed by him. As he does not pretend to the character 

 of a naturalist, perhaps, there were not only the chimney 

 swallow, or hirundo rustica, and martin, or h. urbicot but 

 the swift, or /^. aptiSy and even the sand swallow, or h. ripa- 

 ria. This account, at least, supplies, in some degree, an 

 omission of Mr. Adanson ; who, in his interesting observa- 

 tions on the appearance of swallows in Africa, has omitted 

 to state what species he observed there, or whether he ob- 

 served more than one kind of swallow. 



The preceding extract affords, in my opinion, another Their being 

 argument to prove the annual migration of swallows. That ^°""^ *^"^^f 



" ' . • J J • • water very 



swallows sometimes have been found dormant, in the win- questionable. 

 ter season, in cold climates, I am not disposed to deny. 

 But had a bird so common with us generally remained 

 here all the winter in a dormant state, we, probably, 

 should have discovered it more frequently than has ever 

 been pretended. I will even admit, that swallows have been 

 found concealed amid rushes, by the banks of rivers, in this 

 state: but that they have ever been discovered alive at the 

 bottom of pools and rivers, or otherwise excluded from the 

 access of atmospheric air, we must be permitted to doubt, 

 ^11 it is proved, that the respiratory organs of swallows 



differ 



