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given occafion to the impofition at Bruflels, where they are fhewrr 

 as the mix'd breed of a fowl and rabbit. 



I therefore do not conceive it to be abfolutely neceflary that 

 this tribe of birds mould change their feathers at all, or perhaps 

 they may do fo only the fecond or third year, and at a time 

 different from that in which other birds moult. 



But I will now alk the direct queftion of the partifans of migra- 

 tion, whether the feathers are renewed whilft the fwallow tribe- 

 are in Africa during the winter ? 



Now in all the birds which we are well acquainted with, 

 moulting begins in the autumn ; and therefore if fwallows drop 

 their plumage in Africa during the winter, it is nearly as much 

 contrary to what happens in relation to the change of feathers in 

 other birds, as the not being liable to any change at all. 



It is not alfo abfolutely impoflible that thefe birds may moult 

 during the time of their concealment, to which the fact already 

 mentioned of the Swift's plumage being moft bright and glofly, 

 when it firft appears in the fpring, feems to give fome coun- 

 tenance, and Ariftotle aflerts, that this happens to therpvyuv (com- 

 monly rendered the turtle-dove) whilft it is hid K 



How little do we know, with accuracy, in relation to the re- 

 newal of our own hair; which I rather believe to be brought 

 about by fuch degrees as to be almoft imperceptible, nor are the 

 hair-cutters, or frifeurs, perhaps capable of giving us any mate- 

 rial information on this head. 



Whatever weight, however, thefe anfwers may be thought to 

 carry with them, it is as much incumbent upon thofe who main- 

 tain the migration of fwallows from Europe to Africa, to inform 

 us where and when they moult, as it is upon thofe who deny 

 that they pals from one continent to another. 



i (putei. Arift. Nat. Hift. L. viii. c. 16.. 



