48 



ORNITHOLOGY 



Blasius, of Prof. Cabanis and of Sundevall. To the 

 present writer the order thus prescribed seems to be almost 

 the very reverse of that which the doctrine of Evolution 

 requires, and, so far from the Turdidx being at the head of 

 the Osdnes, they are among its lower members. There is 

 no doubt whatever as to the intimate relationship of the 

 Thrushes (Turdidx) to the Chats (Saxicolinx), for that is 

 not borne admitted by nearly every systematizes Now most author- 

 " '.' l,v ities on classification are agreed in associating with the 

 "' latter group the Birds of the Australian genus Petrwca 

 and its allies — the so-called " Robins " of the English- 

 speaking part of the great southern communities. But it 

 so happens that, from the inferior type of the osteological 

 characters of this very group of Birds, Prof. Parker has 

 called them (Trans. Zool. Society, v. p. 152) " Struthious 

 Warblers." Now if the Prfra'ca-group be, as most allow, 

 allied to the Saxicolinx, they must also be allied, only 

 rather more remotely, to the Turdidx — for Thrushes and 

 Chats are inseparable, and therefore this connexion must 

 drag down the Thrushes in the scale. Let it be granted 

 that the more highly-developed Thrushes have got rid of 

 the low " Struthious " features which characterize their 

 Australian relatives, the unbroken series of connecting 

 forms chains them to the inferior position, and of itself 

 disqualifies them from the rank so fallaciously assigned to 

 them. Nor does this consideration stand alone. By 

 submitting the Thrushes and allied groups of Chats and 

 Warblers to other tests we may try still more completely 

 their claim to the position to which they have been 

 advanced. 



Without attaching too much importance to the system- 

 atic value which the characters of the nervous system 

 afford, there can be little doubt that, throughout the 

 Animal Kingdom, where the nervous system is sufficiently 

 developed to produce a brain, the creatures possessing one 

 are considerably superior to those which have none. Con- 

 sequently we may reasonably infer that those which are 

 the best furnished with a brain are superior to those which 

 are less well endowed in that respect, and that this infer- 

 ence is reasonable is in accordance with the experience of 

 every Physiologist, Comparative Anatomist, and Paleon- 

 tologist, who are agreed that, within limits, the proportion 

 which the brain bears to the spinal marrow in a vertebrate 

 is a measure of that animal's morphological condition. 

 These preliminaries being beyond contradiction, it is clear 

 that, if we had a series of accurate weights and measure- 

 ments of Birds' brains, it would go far to help us in 

 deciding many cases of disputed precedency, and especially 

 such a case as we now have under discussion. To the 

 nor by dispraise of Ornithotomists this subject has never been 

 size of properly investigated, and of late years seems to have been 

 )ram, wholly neglected. The present writer can only refer to the 

 meagre lists given by Tiedemann (Anat. und Naturgesch. 

 der Vogel, i. pp. 18-22), based for the most part on very 

 ancient observations ; but, so far as those observations go, 

 their result is conclusive, for we find that in the Blackbird, 

 Turdus merula, the proportion which the brain bears to 

 the body is lower than in any of the eight species of Oscines 

 there named, being as 1 is to 67. In the Redbreast, 

 Erithacus nibecula, certainly an ally of the Turdidx, it is 

 as 1 to 32 : while it is highest in two of the Finches — the 

 Goldfinch, Carduelis eiegans, and the Canary-bird, Serin/us 

 i inarius, being in each as 1 to 1 I. The signification of 

 these numbers needs no comment to be understood. 



Evidence of another kind may also be adduced in proof 

 that the high place hitherto commonly accorded to the 

 Turdidx is undeserved. Throughout the Class Aves it is 

 observable that the young when first fledged generally 

 assume a spotted plumage of a peculiar character — nearly 

 each of the body-feathers having a light-coloured spot at 



its tip — and this is particularly to be remarked in most 

 groups of Oscines, so much so indeed, that a bird thus 

 marked may, in the majority of cases, be set down with- 

 out fear of mistake as being immature. All the teachings 

 of morphology go to establish the fact that any characters 

 which are peculiar to the immature condition of an animal, 

 and are lost in its progress to maturity, are those which 

 its less advanced progenitors bore while adult, and that 

 in proportion as it gets rid of them it shews its superiority 

 over its ancestry. This being the case, it would follow that 

 an animal which at no time in its life exhibits such marks 

 of immaturity or inferiority must be of a rank, compared 

 with its allies, superior to those which do exhibit these 

 marks. The same may be said of external and secondary 

 sexual characters. Those of the female are almost invari- 

 ably to be deemed the survival of ancestral characters, 

 while those peculiar to the male are in advance of the 

 older fashion, generally and perhaps always the result of 

 sexual selection. 1 When both sexes agree in appearance 

 it may mean one of two things — either that the male has 

 not lifted himself much above the condition of his mate, 

 or that, ho having raised himself, the female has success- 

 fully followed his example. In the former alternative, as 

 regards Birds, we shall find that neither sex departs very 

 much from the coloration of its fellow-species ; in the latter 

 the dej)arture may be very considerable. Now, applying 

 these principles to the Thrushes, we shall find that without nor by 

 exception, so far as is known, the young have their first char- 

 plumage more or less spotted ; and, except in some three ai j ter 

 or four species at most, 2 both sexes, if they agree in 

 plumage, do not differ greatly from their fellow-species. 



Therefore as regards capacity of brain and coloration of 

 plumage priority ought not to be given to the Turdidx. 

 It remains for us to see if we can find the group which is 

 entitled to that eminence. Among Ornithologists of the 

 highest rank there have been few whose opinion is more 

 worthy of attention than Maegillivray, a trained anatomist 

 and a man of thoroughly independent mind. Through the 

 insufficiency of his opportunities, his views on general 

 classification were confessedly imperfect, but on certain 

 special points, where the materials were present for him to 

 form a judgment, one may generally depend upon it. 

 Such is the case here, for his work shews him to have 

 diligently exercised his genius in regard to the Birds which 

 we now call Oscines. He belonged to a period anterior to 

 that in which questions that have been brought uppermost 

 by the doctrine of Evolution existed, and yet he seems not 

 to have been without perception that such questions might 

 arise. In treating of what he. termed the Order Vagatores, 3 Ean '< of 

 including among others the Family Corvidx — the Crows, ( -'"''<'<" v 

 he tells us (Brit. Birds, i. pp. 485, 486) that they "are to 

 be accounted among the most perfectly organized birds," 

 justifying the opinion by stating the reasons, which are of 

 a very varied kind, that led him to it. In one of the 

 earlier treatises of Prof. Paekee, he has expressed (Trans. 

 Zool. Society, v. p. 150) his approval of Macgillivray's 

 views, adding that, " as that speaking, singing, mocking 

 animal, Man, is the culmination of the Mammalian series, 

 so that bird in which the gifts of speech, song, and 

 mockery are combined must be considered as the top and 

 crown of the bird-class." Any doubt as to which Bird is 

 here intended is dispelled by another passage, written ten 



1 See Darwin, Descent of Man, chaps. x\\, xvi. 



2 According to Mr Seebohm (Cat. Birds Brit. Museum, v. \\ 232) 

 these are in his nomenclature Merula •■ ■ . V. fuscatra, M. 

 gigas, and .1/. gigantodes. 



3 In this Order lie included several groups of Birds which we now 

 know to be but slightly if at all allied ; but his intimate acquaintance 

 ■was derived from the' Corvidx and the allied Family we now call 

 Stuniiihi . 



