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COLOUR CHANGES IN BIRDS' FEATHERS, 



inheritance, is conditioned through light, warmth and food in the same way as 

 the creation and disappearance of the chlorophyll in the cell of plants is de- 

 pendent upon light and warmth. It is indeed remarkable that birds of different 

 species living under the same conditions and eating the same food which con- 

 sists of the same chemical ingredients should produce absolutely different colours. 



Undoubtedly the subjective physical colours, that is to say the metallic shin- 

 ing shot colours which change according to light and angle looked at, are caused 

 by feather structure, but light must be a principal factor in the creation of these 

 wonderful colours in tropical birds. It is hard to say what influence temperature 

 would have in the production of these colour effects. My Regent birds which have 

 moulted out in a sunny aviary have reproduced their deep orange colour even 

 after years of confinement, whilst those in a shaded aviary of a friend where 

 sunlight is limited became a pale yellow. The feeding in both instances was 

 the same. 



How the pigment is created within the cells, distributed and enlivened 

 seems to be enshrouded in mystery. 



Besides warmth and food, light, colour changes may be created by selection, 

 and in this way out of Bronze Manakins, Japanese Manakins in three colours 

 have been produced; the yellow and the blue love birds out of the green ones. 

 Further, through adaptation to surroundings, as in the case of quail, etc , or 

 through age and other unknown influences. Very old King parrots will change 

 with age, their scarlet to orange. That light has great influence upon and will 

 even change the colour of dead feathers in live birds I have repeatedly proved 

 to be the case. My experiments with Whydahs and Weavers have shown that 

 when kept in a cage out of the sunshine melanism invariably was produced. I 

 have often noticed the same condition amongst densely packed birds coming 

 from over sea. 



These birds suffering from melanism, placed in a large sunny aviary, would 

 regain their normal healthy natural plumage after the first moult. One wonders 

 how it is that melanism will attack the matured or dead feathers in a live bird, 

 and yet sunlight has no influence upon this condition once it has set in; until 

 the new moult comes around melanism remains. In my long experience with 

 birds in freedom I have never come across one ease of melanism, though I have 

 seen it in rats and mice which are actually born with it. This leads me to believe 

 that I am correct in assuming that it is darkness which produces melanism. I 

 could never find that a blue colour in feathers suffered or was subject to these or 

 other changes. T have noticed, however, that the blue contained in the skin of 

 the bare parts in the face of the Blue faced Honey Eater fades away after a 

 time in captivity. This, of course, has nothing to do with the moult. The Aus- 

 tralian Oriole, whose bare facial parts are scarlet, invariably loses this colour 

 when frightened and it will take weeks to regain it, though it vanishes in a 

 moment. 



In the same way as the food will influence the construction and activity of 

 the animal cell, so it must have an influence upon the kind and 

 the effect of the chemical colour matter. I need only mention the different 

 colours of the canaries which can be produced as red, white, brown, etc. If 

 cayenne pepper is mixed with the food for young canaries the result is red 

 canaries, but if this food is given at a later period, that is to say when the birds 

 are feathered then only the down and small feathers will show the colour change, 

 as only these will be moulted out during the first moult, the larger feathers for 

 the time being remain unchanged, for the reason that this feather is meanwhile 

 dead and the matter changes within the body have ceased. This example is proof 

 that foodstuffs materially influence the colouration of feathers and I am of opinion 



