98 Age of' Northern Birds. . 



birds, is in the impossibility to trace a bird from its birth to its 

 death, except in the case of tame birds, which live a much 

 shorter time than the same species would doubtless do in the 

 wild state, and partly from the advanced age of birds being 

 marked out by no striking phenomenon, and that most of them 

 become a prey to enemies before reaching the natural hmits of 

 existence. 



As far as we know, the larger birds live longer than the 

 smaller. In all, the length of their lives is in direct proportion 

 to that of their unfruitful period, that species living longest 

 which is latest in arriving at maturity. We have some positive 

 observations on this head. The great, age of the eagle is well 

 known : it amounts even to a hundred years, and is several years 

 before breeding. I am acquainted with an instance of a tame 

 fishing eagle, which was taken in the year 1806 out of the nest, 

 and in its tenth year had not received the white tail character- 

 istic of the breeding state. Olafsen notices two eider-ducks, 

 which returned for twenty years to the same breeding-place. 

 The male of this species spends also four or live years in its un- 

 fruitful state. Those species to which the inhabitants of the 

 north attribute a high age, are all more than a single year be- 

 fore breeding, as the Colymhus glacialis, Cygnus musicus, Sula 

 aJba, Falco islandicus. But certainly the age of the swan and 

 the raven is placed too high when estimated at a hundred years. 



According to the ideas which I have on the age of northern 

 birds, and which scarcely admit of being precisely demonstrated, 

 the unfruitful period in those species which are several years of 

 propagating their kind, is to the whole life as one to ten. Up- 

 on this principle, the fishing eagle would live a hundred years, 

 being ten years unfruitful ; the male eider-duck forty years, be- 

 ing four years in the young plumage ; Larus glaucus, marinus, 

 Leucopterus tridactylus^ Sula alba, or solan-goose, and Cephus 

 grylle^ thirty years ; Lestris, Anas clangida^ glacialis, histrio- 

 nictty twenty years, &c. This proportion seems to hold in those 

 smaller species which are only one year before breeding, as the 

 singing tribes, for these little birds scarcely exceed an age of ten 

 years. In the larger species, however, which are only one year 

 of reaching puberty, as most of the Gralla? and of the Palmi- 

 pedes, the guillemot (Uria)^ auk (Alca J, Mormon, the near 



