146 



THE OSPREY. 



mollissiiiia (A Mr. St. Ouiiitin'.s had no food for much to contend with. It looks a.s if Mr. Bar- 



28 days, and a />ii>iini/tii iiiiiiipcs of Mr. Robert rinj^'ton's siif^^-e^tion was rij.,'^ht, yet it must be 



Swinhoe's none for 3,s. The yonn;,'^ i>f />ioiiiitlt'a renieniborod that there are .several sorts of birds 



has been thoug-ht to live on its own fat. and it is that lay a jfood many e}.rf;-s, such as tlie .hisfirs 



said that.//i/<'«()(/r/<-.s (/(■;«(';•.?<; can live two months and Cy!;>ii, which are known ti> be li^nH-'lived. 



without a morsel of food (Ibis, IShd, p, v^24). Weismann and < )ken liavo arg^ued that in St. 



These facts are suj^-f^estive, for surely all such Kilda |Boreray] so many young- Gannets {Sit/a 



famine-proof birds must in the race for life have /la.ssaini) are annually taken for food that, if this 



an advantage over the weaker /'iissiTis and were not a long-lived species, diminution in the 



Picarier. Grass-Finches, Manikins, Waxbills, stock would be observable; and the same applies 



Cut-throats, Ac, whatever maybe the casein to the Fulmar (/•'«/w(;/-«.v i;/(?(7'(;/;.v). This is in 



Africa, can last a very short time without seed some respects rather a false style of reasoning, 



in confinement here in Rngland. Tha Col mil htr because if there were not an annual slaug'hter 



and the '/'r/raoii uf irund /'/msiimidir also coiitaiu there would probably be an antnial throwing off 



genera which seem to want food often, even in of the surplus; but the argument must not be 



a wild state. pas.sed over. If it were admitted, it would apply 



The following is a selection of genera for com- in a less degree to Pi'idi.v liiit'iea and /.a,i;o/>iis 



parison, indicative of their normal length of stu/uus. which are shot by tens of thousands, 



life, from the list of ages to be presently given: — and also to several other birds. 



Years Search as we will, we hardly ever find a bird 



Cockatoo {Caraftta) 81 which has unmistakably died a nattn-al death, 



Goose (.-liiscr) 80 ^nA this has been put forward b3' some authors 



Swan (Cvi;>ii(S) 7(1 as a great argument for longevity. For the 



Raven (Corz'iis) d"' same reason g^reat age has been assig-ned to the 



Owl {Bu ho) 68 elephant, and such elephant-hunters as Sir 



Macaw {.Ira) 64 Sanniel Haker and Col. Pollock declare that they 



Heron (,/;■(/(■«) 60 have never come across the carcass of an 



Bateleur Eagle (/A/(i/(7n(«.s) 55 elephant. Allowing for the quick consumption 



Vasa Parrot ( Coriiiopsis) 54 "^ t'^*^ '^"f* parts by predaceous quadrupeds and 



CoudoT{Sairor/nini/>/iiis)........ 52 burying beetles, one would at least expect to 



Albatross {/>ioiiir</f(i) 46 *i"d t'"-' larger birds' skeletons occasionally, but 



Gull {/.urns) 44 such is very seldom the case. 



Pelican (/V/c((;««.5) 41 "^^^ period of a bird's incubation seems to 



Dove ( Titrtur) .... 40 have .something to do with the length of its life, 



Oyster-catcher (//(^rwa/o/>«.f) 30 albeit \.\^>: Psittad are the principal exceptions 



Emu (Droiiuriis) 28 which invalidate this theory. Referring to Mr. 



William Evan's "Table of Periods of Incuba- 

 Dr. Brehm thought that the smaller birds had tion" (Ibis, \»n. p. 57, 18»2. p. ,55). it will be seen 

 a shorter life than the larger ones, and some that Cockatoos take 21 davs, Cockateels 20, Par- 

 other naturalists have taken up the same idea, rakeets 18, and Macaws from 20 to 25, to hatch, 

 which is not improbable: but it is a theory Three weeks is very little for such a longlived 

 which is mere supposition, and one which is faniilv as this is commonlv suppo.sed to be, com- 

 almost incapable of proof, and I only mention it pared with the incubatioirof manv birds which, 

 as having Brehni's authority. I may here quote according to cmr present knowledge, do not live 

 some remarks from a correspondent who has j,o long as the Puttaci; liut the subject cannot 

 felt the same interest in this difficult matter be worked out without more facts which we have 

 that I have. "One of the puzzles," writes Mr. „ot got at present. Among long-lived birds 

 R. M. Harrington ;;; lit/., "of the ornithological ^hich take a long time in incubation, the prin- 

 census is the uniformity with which birds main- cipal are: 



tain their numbers. The tiuillemot (Vrvi Iniile) „ , v, i. -ir j ir- ^ 



.', J i 1- ■ ■ 1. Ill -nr Pii/io ;H(7,r;w«,\-, about ,55 davs (6«rHci'). 



with one egg does not d.m.n.sh, and the "W ren _^, ^^,^ 3„_3- ^^- ^-,,„„ -,_ 



('I'roglodytes parvutu,) and Teal [Q,,eni,,r,lul,,crecc,,) Sarrorhamphus. 54 davs {Brodcrip). 



do not seem to increase, al hough laying ,l„scr doJc.sticus, 30 daVs U>'<7«.v). 



many more eggs^ The mortality seems in ^.^ „^ ^^^^ 3,^ ^^^ (Slc-ve„so„). 



direct ratio to the birthrate .... It would ■ -^ - " 



seem that, broadly speaking, a bird which lays So far as they go these support the theory, but 



one egg must live longer than a bird which lays unfortunately there are also many exceptions to 



ten, if they both breed once annually." invalidate it. To take only one: a domesti- 



Whether "age" is or is not the solution of this cated Wild Duck requires 28 days to hatch her 



puzzle is a difficult question to answer, — there is egg's, and the domesticated Muscovy Duck 36 



no species of Duck in my list older than 20, and days; but one lives as long as the other so far as 



as to Wrens and Guillemots we know nothing. we know, though poultry-keepers do not com- 



The Guillemot has probably few enemies, and moiily give any Ducks the chance of very g^reat 



the Wren and Eong-tailed Titmouse cannot have longevitj'*. 



*It is generally lield by those best qualified to judge (though not by Prof. Newtou) that there is also some cor- 

 respondence between age and gestation in mammals, at any rale in the larger Mammalia. The subject has lately 

 been revived and ventilated in "The Field' newspaper (see Feliruary fith and l:Jth, ISiiS). und some facts and some 

 theories put forward l)y Col. Pollock and Mr Cameron. I'he idea is as old as Pliny, commenting on whom Wil- 

 lughby and Ray remark": "if Animals of different kinds be compared together, as for example Birds with Mensts. 

 those will sometimes Ije found to be most vivacious [long-lived] which are borne the least while iu the womb" 

 (Ornith., book i. eh. iv). Is incubation in I3irds e(iuivaleut to gestation in Beasts':" 



