Coloration In Birds Research Articles

The iridescent colours of birds and insects

The reflexion spectra of various brilliantly coloured insects are examined in the ultra-violet. Morpho butterflies and Urania moths are found to show ultra-violet maxima in general agreement with the theory of interference. In Morpho achilles the positions of the ultra-violet maxima indicate that the blue colour is due to a reflexion of the second order. Spectra are reproduced. Contrary to some previous accounts, no Morpho butterflies are found to show their blue colour by transmission. They do show brilliant diffraction spectra by transmission, when suitably mounted in balsam, but these have nothing to do with the blue reflexion.

The iridescent colours of birds and insects

It cannot be said that there is yet general agreement as to the origin of the brilliant iridescent colours met with in the animal kingdom, though the balance of opinion attributes them in most if not in all cases to interference of light rather than to any action of pigmentary substances. In the present paper it has been my object to apply methods of investigation which seemed to have been insufficiently exploited by previous workers, in the hope of obtaining further evidence, rather than of supporting any preconceived ideas. On account of this method of attack the record of work will be subdivided rather according to the form of experiment than according to the animal species investigated.

XLI.—Recent Investigations on the Colours of Birds' Feathers.

XLI.—Recent Investigations on the Colours of Birds' Feathers.

On the Revealing and Concealing Coloration of Birds: An Unpublished Letter by Theodore Roosevelt

Journal Article On the Revealing and Concealing Coloration of Birds: An Unpublished Letter by Theodore Roosevelt Get access Theodore Roosevelt, Theodore Roosevelt University of California, Berkeley Search for other works by this author on: Oxford Academic Google Scholar Charles A. Kofoid Charles A. Kofoid University of California, Berkeley Search for other works by this author on: Oxford Academic Google Scholar The Condor, Volume 26, Issue 3, 1 May 1924, Pages 94–98, https://doi.org/10.2307/1363106 Published: 01 May 1924

Effect of Light on Colour of Birds

Effect of Light on Colour of Birds

The Coloration of Birds' Eggs

The Coloration of Birds' Eggs

On certain factors concerned in the production of eye colour in birds

On certain factors concerned in the production of eye colour in birds

Protective Coloration of Birds and Eggs

WHILE collecting information on the use of colour-protection among birds, my attention has been directed to what appears to be a very interesting generalisation, viz. that among birds which nest on the moors, sea shores, and similar open places, (1) those which have the habit of remaining on their nests when danger threatens generally wear camouflaged uniforms, but their eggs seldom show any signs of colour-protection; while (2) those which are very shy and leave their eggs readily are generally conspicuously coloured, but their eggs are usually camouflaged.

The Colour of the Scales of Iridescent Insects in Transmitted Light

CURIOUS as it may seem, the origin of the brilliant metallic and iridescent colours in birds and insects has never been satisfactorily explained, though it is generally supposed among naturalists and others that they are in some way produced by the interference of light at the surfaces of thin plates, as in the o soap-bubble.

Remarks on the Case of Roosevelt vs. Thayer, with a Few Independent Suggestions on the Concealing Coloration Question

COLONEL ROOSEVELT in his recent paper on 'Revealing and Concealing Coloration in Birds and Mammals' 1 makes an attack on the work of Messrs. Abbott H. and Gerald H. Thayer and sounds the slogan of 'common sense' as against the Messrs. Thayer's 'wild absurdities,' as he is pleased to term some of the views set forth in their book. Other persons have spoken approvingly of the sound 'common sense' of Roosevelt's paper. Now common sense is an excellent thing; I might go farther and call it indispensable; and yet, with the greatest respect for it, we must admit that it has its limitations. In Columbus's day common sense declared that the world was flat. More recently it carefully protected the consumptive from 'night air.' And, if I mistake not, it is still an obstacle to the spread of scientific education. It is hardly safe, I think, to trust to common sense alone to settle the question of concealing coloration or any other scientific question. It is science that must settle it, though she must call on both common sense and imagination to help her,imagination as well as common sense, for one without the other would be only a hindrance. Any science that goes deeper or soars higher than the mere accumulation of facts must make use of the imagination.2 This is a truism, of course, but it seems necessary to insist upon it a little under the circumstances. And we must also face the fact that it is not always the best, i. e. the most accurate and diligent, observer that makes discover-

Note on the iridescent colours of birds and insects

Considerable interest attaches to the origin of certain forms of brilliant colouring which are of frequent occurrence in the animal world, though hardly represented among plants. The colours in question are those which are not due to ordinary pigment, and which change with the angle of incidence of the light. The most brilliant examples are to be found amongst birds and insects. Fishes, and a few reptiles, exhibit colours of the.same kind, but not so conspicuously. During the last 10 or 12 years I have examined some hundreds of cases of this sort of colour production, and quite recently Michelson has published investigations on the same subject, and refers to a somewhat similar paper by Walter, “Oberflächen and Schillerfarben,” dated 1895, of the existence of which I was not before aware.

The Colours of Fishes

INTEREST as to the sources of colours in birds and insects has been revived by Prof. Michelson in The Philosophical Magazine for April, and by Mr. Mallock at the Royal Society. The inquiry will be assisted if fishes may also be included. Nature reveals no more vivid form of shifting tints than we see in the common mackerel, which is a fish without scales. In August I was able to watch them immediately after the fish had been taken from the sea I was surprised to find the skin so firm and tough; I almost expected to spoil it in handling; the delicate colours seem as if they might be tender like the bloom of a grape. With the smooth, but not sharp, edge of a knife I scraped the surface somewhat vigorously without damaging the lovely play of blue and green light.

The Birds of Homer

It was with some misgiving that I set out in my attempt to identify the birds referred to by Homer in the Iliad and the Odyssey. His greatness as a poet seemed to offer no guarantee of his faithfulness as an observer in an age when science as such did not exist, and the spirit of accuracy it begets was as yet unawakened. Moreover, I had long observed Homer to be before all else a poet of action. His references to natural objects are largely by way of illustration—short, crisp asides, as it were, in which the selected word and the packed phrase reveal the economy of his art in matters subordinate to the main theme. His references to colour in birds are extremely rare; those regarding form are epithetic, and recur with something of the conventional formality of the epithets applied to his heroes. However, whether in the form of epithet or by special description, Homer's portrayal of birds deals chiefly with essentials. In this lie the advantage and the disadvantage of the Homeric method for one whose main purpose is concerned with what in Homer was merely contributory to a fuller one. The advantage of such a method is that it forces essentials to the front, and the disadvantage, that the references to these may be limited by the nature of the matter they serve to illustrate; or that, being references to the characteristics of a class of birds, they may not suffice for the identification of a particular member of that class.

Societies and Academies

Societies and Academies

Roosevelt's 'Revealing and Concealing Coloration in Birds and Mammals'

Roosevelt's 'Revealing and Concealing Coloration in Birds and Mammals'

Bird Notes

TO the July issue of the Quarterly Review Dr. H. Gadow communicates an instructive article on the nature and meaning of the colours of birds. After pointing out the fallacy of the idea that the colouring of such birds as the scarlet ibis or white egret can be in any sense protective, the author discusses the diverse means by which colour is produced in birds, showing that while black and the red and yellow group are pigmentary, blues and greens are so-called structural tints, due to the reflection from the surface of the feathers of an undue proportion of short light-rays. Metallic colouring, which usually occurs in black feathers, is due, of course, to another cause. Dr. Gadow next proceeds to describe the sequence in which various colours replace one another with the advance of specialisation. As regards the cause of colour-specialisation, the author rejects both natural and sexual selection, remarking that if the latter were the inducing factor, every group and species would have its own taste, and each individual would strive to develop its yellow patches into orange and then into red. For the explanation offered in place of natural and sexual selection, we must refer our readers to the article itself.

Coloration of Birds' Eggs

SOME time ago I wrote a short letter asking for information about the colours of birds' eggs, which appeared in NATURE of May 14, 1908. I read the answer to my letter in a subsequent number of NATURE, which, unfortunately, did not appear to me to throw much light on the subject. I would like to suggest that this colouring of eggs was in some way originally analogous to the change of colour observable in the chameleon and certain lizards, though by no means, at the same level of development. Although it is quite possible that the colouring in some cases is protective, or has become so, it does not seem that this is a fixed rule. Why should the egg of a starling, which generally builds on house-tops, be blue? The hedgesparrow's, again, is blue, while the thrush's is blue spotted with black, and the blackbird's is green, though the position of their nests is vastly similar. Again, on examining the excellent “clutches” at the Natural History Museum which exhibit the additional cuckoo's egg, one is struck by the variation in shade, which, according to observers, is matched by the bird itself.

The Coloration of Birds' Eggs

WITHOUT wishing to trespass further than I can help upon the space at disposal for discussing this topic, I may just explain that in my reply to Mr. Leslie, June 11, 1908, I distinctly gave it as my opinion that coloration had no connection with Mendelian principles. I concluded that coloration often depended on habitat, and was now useful as a means of protection; but the habitats (and nesting sites) of birds change, hence the anomalies met with which are cited as difficulties.

Beebe on the Seasonal Changes of Color in Birds Preliminary Report on an Investigation of the Seasonal Changes of Color in Birds C. William Beebe

Beebe on the Seasonal Changes of Color in Birds Preliminary Report on an Investigation of the Seasonal Changes of Color in Birds C. William Beebe

The Coloration of Birds' Eggs

WITHOUT wishing to trespass further than I can help upon the space at disposal for discussing this topic, I may just explain that in my reply to Mr. Leslie, June 11, 1908, I distinctly gave it as my opinion that coloration had no connection with Mendelian principles. I concluded that coloration often depended on habitat, and was now useful as a means of protection; but the habitats (and nesting sites) of birds change, hence the anomalies met with which are cited as difficulties.