THE OSPREY. 



An lllustr«.ted \/i.a^azine of Popular Ornithology. 



Published [S^onthlv except in July and Auy6st. 



VOLUMK 111. 



JUNE, 1899 



NUMBBR 10. 



Original Articles. 



ON THE COMPARATIVE AGES TO WHICH BIRDS LIVE.* 

 r,v J. H. GuKNEv, F.X.S. 



How many thins^ there are in ornith<ilo};-y. in 

 spite of our boastin^;- proficiency at tlie present 

 day, of which we are really profoundly ig-nor- 

 antl And one of these is the ag-e of birds. Who 

 can say what g-uides birds on mi'4ration, in spite 

 of all which has been written on the subject— 

 whether any of them have the power of sniel- 

 liii^,'-- what their powers of vision are. or even 

 wliat becomes of them when they are dead? 



There is still much difference of opinion as to 

 whether many species moult the major part of 

 their plumaj^-e or recolour. and the best ornitho- 

 loijists are divided as to the heiifht at which birds 

 mig-rate, the speed at which they go, and the ag-e 

 to which they can, under the most favourable 

 conditions, live, which is the subject of the pre- 

 .sent paper. No one, up to now, has been at the 

 pains to collect and compare the facts about age 

 scattered in many books, but I hope to make at 

 least a step in tliat direction. Birds are not to 

 be compared to human being's. Thej' are in 

 truth handicapped in the race for life, for it is 

 ordained that all the feathered tribes .should be 

 very much expo.sed to death from a great many 

 accidental causes. We may so call death fnnn 

 insufficiency of food (oftenest arising from the 

 extremes of heat and frost), from ravenous 

 Hawks and (jther predaceous animals, and from 

 tlie hand of man with his gun and snare. 

 Almost every species of bird migrates, and they 

 have to reckon on .storms during migration, 

 which doubtless dash them into the sea in hun- 

 dreds every year. 



Because of these perils, it may well be believed 

 that not one bird in fifty reaches its full possi- 

 ble duration of life, perhaps not one in two hun- 

 dred. However, the subject for di.scussion in 

 this article is not the average to which birds 

 commonly live, but rather the full e.xtent of age 

 to which they can live, all things being in their 

 favour; but "both divisions of the subject are in- 

 teresting-, and I am surprised that no recent 

 writer has inquired into them. 



The Great Lord Bacon, in his treatise on 

 'Leng-th and Shortness of Life in Living- Crea- 

 tures,' has a g-reat deal to say about the age of 

 birds, and concluded that more kinds were found 

 to be long-lived than of beasts, setting forth 

 various reasons why this was probably so. He 

 particularly lays emphasis on the mixed motion 

 of birds in' their flying, as being a kind or exer- 



cise conducive to longevity, which is denied to 

 beasts, and he assigns to .several .sorts what was 

 believed to be the maximum of their longevity 

 in his day. 



Willug'hby and Ray (1(5761, the pioneers of 

 British Ornithology, devote a chapter to "The 

 Age of Birds," which shows that attention had 

 been turned to the subject by older authors than 

 themselves, like Aldrovandus. Something also 

 uiay be found in Philos. of N. H. ii. p. 416, and 

 in '-Domestic Habits of Birds," 1833, from the 

 pen, I believe, of Prof. J. Rennie; but the liter- 

 ature of the subject in modern times is very 

 scant}', though a certain number of incidental 

 notices are scattered about such journals as 'The 

 Field' newspaper and 'The Zoologist.' 



In Thompson's 'Birds of Ireland' (1851) there 

 is a useful article, and in 'The Naturalist' for 

 18')7, p. 129, there is a paper by Mr. Oxley Grab- 

 haui on "Owls and their Longevity." Allusion 

 should also be made to Mr. W. B. Tegetmeier's 

 article on "Length of Life in Zoological Collec- 

 tions" ('The Field,' June ,5th, 1869). ' 



Again, in Knapp's 'Journal of a Naturalist,' 

 the duration of animal life is discussed at p. 180. 

 Remarking on the longevity of the Eagle, 

 Raven, and Parrot in a captive condition, the 

 author opines that "in a really wild state the)' 

 would expire before the period which they attain 

 when under our attention and care:" and again 

 he says "it is probable that few animals in a 

 perfectlv wild state live to a natural extinction 

 of life."" 



It is easier to subscribe to the second opinion 

 here expressed than to the first. Cage-birds are 

 too often neglected to have an easy time of it, 

 but perhaps a semi-demesticated bird like Cygtiiis 

 olor has the best chance of longevity of any. 



It is more than probable that some families, 

 and it may be even allied genera, attain a 

 greater age than others, and to elicit informa- 

 tion on this head has been the chief object of 

 inquiry. The tenacity of life in Sarcoi'lia>npi)tus 

 gryp/itis and Ciyps Jii/viis is great, and all Eag-les 

 and carrion-eating birds are reputed to exist a 

 long time without food; a neglected Aquila 

 c/irvsactus, for example, live 21 days, and most 

 Birds of prey are capable of subsisting for 

 months without water. 



Some of the sea-birds can fast a very long 

 time, such as Puffiiuis aiii^lontin. A Soi)iatcria 



♦Communicated by the Author and reprinted -with some revisions from THB Ibis (London) for January, 18iia. 



