76 



NA TURE 



LDecemp.er 26. 1895 



(lent sortant, Lord Kelvin, et le nouveau President, Sir J. Lister, 

 exprimer les liens d'estime, de reconnaissance et d'amitie qui les 

 attachent aux savants fran9ais. Dans presque tous les discours 

 qui ont ^te prononces, des paroles emues temoignaient de I'ad- 

 miration que nos voisins professent pour notre regrette Pasteur. 



"Je crois avoir ete lefidele interprete des sentiments qui nous 

 animent tous en assurant les membres de la Societe Royale de 

 notre estime et de notre sympathie et en rappelant combien nous 

 avons ete touches de rempressement avec lequel nos Confreres 

 et nos Correspondants anglais sont venus celebrer les fetes du 

 Centenaire de I'lnstitut de France. 



" Un autre motif encore m'avait valu I'honneur d'etre invite 

 par la Societe Royale. Cette savante Compagnie entreprend un 

 travail d'une haute importance pour la Science ; il s'agit de la 

 creation d'un grand Catalogue international, rassemblant tous les 

 travaux publics chaque annee dans le monde entier sur toutes les 

 branches de la Science. 



" La plupart de nos Confreres connaissent deja le magnifique 

 Ouvrage dans lequel la Societe Royale a rassemble, sous le nom 

 de chaque auteur, les titres des travaux publics en tous pays 

 depuis I'annee 1800 jusqu'a nos jours. Chacun peut trouver, 

 dans ce Recueil, la serie de ses propres publications : Livres, 

 Memoires et jusqu'aux moindres Notes y sont classes par ordre 

 chronologique, avec indication precise du titre et de la date de 

 leur impression. Mais un tel Recueil, excellent lorsqu'il s'agit 

 de retrouver les travaux successifs d'un auteur, se prete mal aux 

 recherches bibliographiques . sur un sujet donne. C'est pour 

 combler cette lacune que la Societe Royale veut entreprendre 

 I'oeuvre colossale dont je viens de parler. 



" Dejabeaucoup d'entre nous ont ete pressentis relativement a 

 I'opportunite d'un tel travail, et c'est sur I'avis favorable de notre 

 Compagnie que la Societe Royale a resolu de faire adresser 

 diplomatiquement a tous les Gouvernements la demande de 

 designer des delegues pour une Conference internationale, 

 destinee a rechercher les meilleurs moyens de realiser cette 

 publication. Jusqu'ici, les reunions du Comite du Catalogue de 

 la Societe Royale n'ont ete que preparatoires ; il semble toute- 

 fois que, sur certains points, I'accord doive etre unanime. II 

 faut, par exemple, que le titre de chaque travail en indique 

 aussi explicitement que possible la nature et les conclusions ; il 

 faut que les titres de certaines Notes se repetent en differents 

 points du repertoire, lorsqu'elles se rattachent naturellement a 

 plusieurs sections du Catalogue. Sur tous ces points, et sur bien 

 d'autres encore, la Commission internationale devra statuer. 



" L'importance de I'entreprise ne parait pas discutable, le 

 nombre toujours croissant des publications scientifiques rend 

 aujourd'hui presque impossible la connaissance des travaux 

 effectues sur un sujet donne ; les revendications de priorite 

 occupent, dans les Ouvrages scientifiques, une place excessive, 

 et beaucoup de savants depensent en pure perte des mois et des 

 ann^es pour avoir ignore des travaux anterieurs sur I'objet de 

 leurs etudes. 



' ' La question est du reste a I'ordre du jour ; plusieurs 

 Societes savantes ont deja des Catalogues tres complets , d'autres 

 sont moins bien partagees, mais peuvent deja fournir de precieux 

 elements pour le travail d'ensemble. L'^merique, la Belgique, 

 la France et plusieurs autres nations ont dernierement realise de 

 grands progres dans la maniere de cataloguer les publications 

 scientifiques. On peut done esperer que, si Taction diplo- 

 matique est assez prompte, les delegues des differentes nations 

 pourront se mettre a I'oeuvre des I'annee prochaine et feront 

 concentrer pour un travail commun toutes les forces eparses 

 aujourd'hui. 



" Dans I'esprit de la Societe Royale, les dernieres annees de ce 

 siecle seraient consacrees a introduire, dans le classement des 

 documents scientifiques, tous les perfectionnements que I'ex- 

 perience montrera necessaires, afin que, des I'an 1901, I'oeuvre 

 puisse se poursuivre regulierement dans sa forme definitive. 



" Tels sont les points qui ont ete discutes dans la seance du 

 Comite a laquelle j'ai eu I'honneur d'assister et que je me suis 

 charge de vous transmettre officieusement, en attendant que 

 notre Compagnie en soit saisie d'une maniere officielle." 



THE HABITS OF THE CUCKOO. 

 T N an interesting and very valuable series of papers, 

 ■■■ published in the Journal fur Ornithologie, and 

 the Ornith. Monatschrift, Dr. E. Reh records his latest 

 observations on the parasitic habits of the common 



NO. 1365, VOL. 53] 



cuckoo, which seem to entirely confirm what he has. 

 already given us in his larger work, " Altes und Neues 

 aus dem HaushaUe des Kuckucks." 



In 1893, not more than two kilometres from Leipzig, 

 no less than 70 nests were found containing cuckoo eggs ; 

 of which, 58 (83 per cent.) were in nests of the Red-backed 

 Shrike (Lanius collurio). 



In this year it was observed that five females were 

 missing, while at the same time eight females were 

 detected as new to the locality. Four new foster-parents 

 were also noted. An approximate balance is thus pre- 

 served. Fresh arrivals are recognised by means of their 

 eggs ; for Dr. Reh finds that the colouration of the ^^■g 

 of every female is peculiar to itself, and constant. Each 

 cuckoo returns every year to the same locality, and lays 

 its eggs only in the nests of that particular species which 

 it, or its ancestors, happen to have adopted for that pur- 

 pose. Thus, not only can every egg in a district be 

 identified, but the number laid by any given female can 

 be determined with a tolerable degree of accuracy. 



This yearly census of the cuckoo population seems to^ 

 show that the young do not return to their birthplace to 

 breed ; or that, if they return, they do not succeed in 

 laying eggs, being driven away by the parent birds. 

 The evidence for this view is based partly on the fact that 

 the numbers remain approximately fixed for each locality,, 

 and partly on the assumption that the egg of the daughter 

 cuckoo would be similar to, but not exactly like that of the 

 parent. It has been found, however, that the eggs which 

 are presumably new to a locality are of types totall}' 

 distinct from the types of eggs laid by birds which, so to 

 speak, belong to the neighbourhood. 



Cuckoos would seem to be more prolific than is 

 generally supposed, an egg being deposited on alternate 

 days from the middle of May to the middle of July. 

 Occasionally it happens that an &'g% is laid every day for 

 a short period, but such an occurrence is rare. Sometimes 

 two eggs are found in the same nest. Such cases- 

 can always be referred to particular birds which seem to 

 have a tendency to colonise, as is the case with an 

 American ally, Crotophaga. 



It is related that on one occasion a male cuckoo was- 

 seen leaving a shrike's nest, noisily calling the while, and 

 pursued by one of the infuriated owners — whether male 

 or female could not be determined — until at length both 

 were lost to view. The whole proceeding produced the 

 impression that the male had purposely provoked the 

 chase in order to give the female time to deposit its ^^g. 

 When the shrike returned it was accompanied by its 

 mate. On the previous day this nest had been found 

 empty ; at 3 p.m. on the afternoon on which the chase 

 occurred it contained one shrike's ^^^ ; on a third 

 inspection it was observed that a cuckoo's egg had been 

 added. 



As an additional piece of evidence in support of the 

 contention that the cuckoo first deposits its ^^% on the 

 ground and thence carries it to the selected nest, Dr. 

 Reh quotes a case in which a cuckoo's ^■gg was found 

 smeared with red earth similar to that which occurred i» 

 the immediate vicinity of the nest from which this egg 

 was taken. 



As is well known, cuckoos' eggs found in the nests of 

 some species of host diflfer widely one from another in 

 colouration, while those from the nests of certain other 

 species show a great similarity amongst themselves. 

 Dr. Reh points out further that precisely the same features- 

 obtain among the species with which these eggs are 

 found. Thus cuckoos' eggs from nests of the red-backed 

 shrike show a wide dissimilarity in colouration, but not 

 more so than do those of the shrikes themselves ; but, on 

 the other hand, cuckoos' eggs from the nests of the wren 

 exhibit great uniformity of colouration, just as do those of 

 the host. As an explanation of these facts, it is suggested 

 that this variability is due to the nature of the food upon, 



