SIRDS. 23 



plumage ; but then the smjiller kinds make up for this defect by 

 the melody of their voices. The birds of the torrid zone are 

 very bright and vivid in their colours ; but they have screaming 

 voices, or are totally silent. The frigid zone, on the other hand, 

 where the seas abound with fish, arc stocked with birds of the 

 aquatic kind, in much greater plenty than in Europe ; and these 

 are generally clothed with a warmer coat of feathers ; or they 

 have large quantities of fat lying underneath the skin, which 

 seiTCS to defend them from the rigours of the climate. 



In all countries, however, birds are a more long-lived class 

 of animals than the quadrupeds or insects of the same cli- 

 mate. The life of man himself is but short, when compared to 

 what some of them enjoy. It is said that swans have been known 

 to live three hundred years; geese are often seen to live four- 

 score ; while linnets and other little birds, though imprisoned 

 in cages, are often found to reach fourteen or fifteen. How 

 birds, whose age of perfection is much more early than that of 

 quadrupeds, should yet live comparatively so much longer, is not 

 easily to be accounted for : perhaps, as their bones ai-e light- 

 er, and more porous than those of quadrupeds, there are few- 

 er obstructions m the animal machine ; and nature thus finding 



plyinj the heat were attended to ; for death, in most cases, seems to be pro. 

 duo'd not by the cold, but by the incautious application of heat, which 

 bursts the vessels and destroys the texture of the body. It is well known 

 that if any part of the body be frost-bitten, an incautious application of heat 

 infallibly produces mortification, and destroys the part. There is a re- 

 markable example, in the 28th volume of the Philosopliical Transactions, 

 page 265, of a woman almost naked lying- buried for six days under the 

 snow, and yet recovering. In this case it is scarcely possible to avoid sup. 

 posing that the woman must have been in a state of torpor, otherwise she 

 would certainly have endeavoured to find her way home. 



Many authentic facts prove the migration of our summer birds ; and that 

 they desert temperate zones at the approach of winter to seek a better 

 climate in lower latitudes. Besides all the tribe of birds of passage feed up. 

 on insects, which disappear and become torpid, either in a perfect or em- 

 bryo state, soon after the autumnal equinox : they are therefore compelled 

 to migrate southward, in search of their natural food. 



'1 he ^vintor birds of passage forsake the frosty confines of the arctic circle, 

 to spend the winter in the more temperate parts of Europe : the jacksnipe, 

 redwing, woodcock, and fieldfare are of tliis tribe. About the end of April 

 they return to the north, to pass the breeding season. It is also well kuo\vn 

 that swallows winter in different parts of Africa, 



