It was announced that, in conformity with the Act, Mr. Charles Hulke had been nominated to vote in the election of Governors of the New Zealand Institute for the ensuing year.
Papers.—1. “An Exhibition of New and Interesting Forms of New Zealand Birds, with Remarks thereon,” by Sir Walter Buller, K.C.M.G., F.R.S. (Transactions, p. 36.)
Mr. Maskell said the remarks made by Sir Walter Buller, who was an acknowledged authority on the subject of ornithology, were most interesting, and the specimens exhibited very beautiful. Without wishing to make any reflections on the work done by Sir Walter Buller, he would like to say a few words regarding the establishment of species. It was common in almost all branches of science to establish what were called species on grounds that seemed often very unsatisfactory, and from his own experience and reading for over twenty years he was led to the conviction that scientific works generally were overloaded with species determined in a very vague manner. This applied to all branches of natural science. Mere difference in colours seemed sufficient to account for thousands of so-called species, when probably the birds, or insects, or animals were really the same, or only slightly varied. He thought it would be quite as correct to say that all bay horses were of one species and all black horses another, as to say that birds in other respects alike were of different species because they were different in colour. Why should science be so loaded with such small differences, especially as so few agree as to colour, which depends so frequently on the formation of the human eye? If there were organic differences, that would be quite another matter.
Mr. Hudson would like to remind Mr. Maskell that domestic productions varied more than those in a wild state, because in selecting animals and plants for his use man has always taken those that vary in the direction he required; hence domestic animals and plants had a tendency to vary in all directions.
Mr. Robert Pharazyn said that the question was largely one of experience—there were some branches of science where colour would not apply, such as chemistry. In natural history colour would have greater weight, but it was really for naturalists themselves from experience to judge. If difference of colour proved to be followed by difference in structure or habit, then it would certainly be reliable. Animals were much alike in habit, and it would hardly apply to them. We must associate colour with other characters before it could be generally used in selecting species.
Mr. McKay said that colour was often the result of a structural peculiarity, and in many instances must be regarded as specific: nacreous and iridescent shells might be mentioned as illustrating this. While believing that colour was never purely accidental, as contended by Mr. Maskell, he did not think that colour-spots in all cases could be used to determine specific differences. With respect to the occurrence of a species of robin on the Snares and Chatham Islands, but not found elsewhere within the New Zealand area, he thought this might be accounted for on the supposition that the species had established itself on these now separate and distant islands at a time when the Snares and Chatham Islands were connected with each other, and formed part of a large island which also included New Zealand.
Mr. Henley thought the establishment of true species was a matter that was determined by the instincts of the animals themselves. In the cases of tamed quadrupeds, referred to by Mr. Maskell, the animals recognized no distinction—to a horse every other horse was also a horse; every dog recognized his species in any other dog. If this were not so,—if grey horses refused to associate with bay horses, and if, except in cases of close confinement, horses of the two colours did not cross,—they might fairly be considered to be two species. If they did not cross the colours would be persistent, as a rule, in the offspring. In cases of wild animals and birds, if individuals different in colour, but seemingly alike in other respects, never coupled, the colour alone noted a difference of species. Whether this instinct for separate breeding was likely to be present in special instances of birds with peculiar-coloured plumage, only one or two specimens of which birds had been collected, only a specialist was competent
to decide, and he would probably base his opinion upon points the cumulative force of which, sufficiently plain to himself, he might find it difficult to explain to others. If albinos were sporadically produced in sufficient numbers to find albinos for partners, and never obtained partners of the normal colour of the species, they would probably have a large proportion of albinos in their offspring, which would soon form a species that he thought all naturalists would acknowledge as such.
Mr. T. W. Kirk mentioned having seen a specimen of the nankeen night-heron near the mouth of the Pahau River in March last. The bird had been slightly wounded, but managed to escape capture. Sir Walter Buller had exhibited an albino tui. Now, it was well known that birds in New Zealand showed a decided tendency to assume abnormal plumage. Nor was the peculiarity confined to native species. There was in the Museum a black skylark; he had seen several specimens of goldfinch exhibiting unusual colours; and early this year he had noted a sparrow having white wing-feathers, black head, and normal-coloured tail, while the whole of the remaining portions were a decided red. This specimen lived with a large flock of ordinary sparrows about a woolshed on the East Coast. Could Sir Walter Buller suggest any theory to account for these frequent freaks? Also, could he explain the reason why dimorphic phases of plumage were present in some species?
Mr. Richardson pointed out that on the Kermadec Islands the mutton-birds were so numerous as to form an article of food for those who were unfortunate enough to live there.
Sir Walter Buller, in reply, said that the only importance he attached to systematic classification was as an aid to memory in the study of the natural objects themselves. Birds, like other animals, resolved themselves into natural groups, and could be most conveniently studied in that manner. The discrimination of genera and species was, after all, empiric, and often very arbitrary. Nothing was easier than to raise the quæstio vexata, What constitutes the difference between a species and a permanent variety? On no point probably were naturalists so much divided—some carrying their discrimination of forms to an extreme, others erring in an opposite direction. In fact, most systematists might be divided into two classes, “lumpers” and “splitters.” The thing was to hit the happy mean. There was much truth in what Mr. Maskell had said, and no doubt modifications of structure were of the first importance in the discrimination of species; but, as to nomenclature, it seemed to him that simplicity was the thing above all others to be desired. To adopt the system more or less in use among ornithologists of making subspecies or varieties was to his mind very objectionable, because it had the effect of encumbering the literature with names. For example, Apteryx bulleri, as it was now called, appeared in Dr. Finsch's list as Apteryx australis, variety mantelli. According to the generally-accepted view among English systematists, the amount of variation necessary to constitute a species was not of much importance, and might be left to individual opinion, so long as it was persistent or constant. For his own part, he was quite indifferent whether the petrel now exhibited, and which he had named Œstrelata affinis, was regarded as a distinct species or a permanent race, so long as the difference of character was recognized. Admitting the distinction, it was merely a question of convenience with systematists whether to call it by a distinctive name, or to designate it “Species A, variety B.” Dr. Finsch considered that this and Œstrelata mollis, of which specimens were on the table for comparison, were varieties of one and the same species; but Mr. Osbert Salvin, our great authority on petrels, had unhesitatingly pronounced them distinct species. They belonged, however, to the same natural group, and were closely allied. Although easily discriminated now, no naturalist of the present day would deny that they had originally sprung from a common parent. This followed of necessity from an acceptance of the theory of
evolution. As to the alleged worthlessness of colour as a criterion for discriminating species, he could not agree with Mr. Maskell, because our whole experience was opposed to such an argument. The cases put forward by that gentleman were not in point. For example, the condition of the albino tui exhibited that evening was due to an accidental absence of the colouring-pigment in the feathers. It was merely a lusus naturæ, or a freak of nature. However many examples of this kind might be met with, no naturalist of any experience would think of creating a new species out of such material. So in the case of individual peculiarities of plumage mentioned by him. No one would pretend that these were of specific value. For example, the red grouse (or brown ptarmigan), one of the commonest birds of Great Britain, is so variable in colour that scarcely two males can be found with precisely the same markings; and this was likewise the case with the common albatros and some other sea-birds. This variability of plumage became, then, a character of the species. But if you met with, say, two forms of seagull, one having a black head and the other a white head, breeding true, and presenting this constant character, an ornithologist would, as a matter of course, treat them as distinct species, although he might not be able to discover any other points of difference. On the other hand there was a phase of colouring known as dimorphism, which obtained among some species of sea-birds—some individuals being dark and others white in one and the same species. Other birds, again, passed through several distinct phases of plumage in their progress from youth to maturity. These adolescent states, and the known instances of dimorphic coloration, did not by any means affect the argument that colour is an important external character in the determination of species. On the main question, however, of manifest structural or organic difference as the surest guide in the differentiation, Sir Walter Buller said that he quite agreed with Mr. Maskell. He would remind the meeting that the study of birds had often to be prosecuted with nothing before the investigator but skin and feathers, and that the systematist could only make the most of the materials before him. He did not believe that it would be possible to attain perfection in classification till the internal characters and anatomy of every known bird had been as completely examined and illustrated as that of the common rock dove (Columba livia) had been by the late Professor Macgillivray.
The President said he was glad that Sir Walter Buller's remarks, which were most interesting, had brought on such a general discussion. The great thing in the determination of species was to have the characters, whether of colour or otherwise, persistent, and this would no doubt be sufficient grounds for forming a species.