LONGEVITY OF BIRDS. 203 



a considerable distance." In the Old "World, choosing a time when 

 the winds are favourable, most migratory birds direct their flight 

 towards the south-west in the autumn, and the north-east in 

 spring. In America the migratory birds take a south-east direc- 

 tion in autumn, and the reverse in spring. These aerial travellers 

 instinctively direct their flight to the same regions often to the 

 same district ; and there are good grounds to believe that the same 

 pair frequently find their way year after year to the same nest. 



The duration of the life of birds in a state of nature is one of those 

 subjects on which little is known. Some ancient authors Hesiod 

 and Pliny, for example give to the Crow nine times the length 

 of life allotted to man, and to the Eaven three times that period ; 

 in other words, the Carrion Crow, according to these authors, attains 

 to seven hundred and twenty years, and the Raven two hundred 

 and forty. The Swan, on the same authority, lives two hundred 

 years. This longevity is more than doubtful. Paroquets, how- 

 ever, are known to have reached more than a hundred. Goldfinches, 

 Chaffinches, and Nightingales unquestionably, even in the con- 

 finement of a cage, have lived four-and-twenty years. A Heron, 

 Girardin tells us, lived fifty-two years, which was testified by 

 the ring which he bore on one of his legs, and even then 

 he lost his life by an accident, while in full vigour. A couple of 

 Storks, moreover, have been known to nestle in the same place for 

 more than forty years. All that we can affirm is that birds live 

 much longer than the Mammalia. 



We can easily fix a circumscribed geographical boundary to any 

 species of Mammalia. They may be limited to a country, or even 

 a district. Can we impose a like distribution on birds ? At first 

 sight this seems difficult : their powerful organs of locomotion 

 permit of their travelling rapidly ; and, moreover, their nature, 

 essentially mobile, and their wandering humour, lead them to 

 continual change; and then their organisation adapts them for 

 great extremes of temperature circumstances which would lead 

 us to consider them quite cosmopolite. Nevertheless, many species 

 reside habitually in countries of very limited range. A Sovereign 

 Hand has traced on the surface of the globe limits that cannot 

 be passed. How such small creatures are able to perform such dis- 

 tant journeys, pausing only at far-severed resting-places for neces- 



