Vu !j,^ m ] Allen, Gattes 'Heligoland: 1 49 



moult, or he would not, as on page no, consider it "singular how 

 such a bird [as the Hooded Crow] could lose so many of the flight 

 feathers of both wings " at the same time, or fail to recognize a 

 spring moult in so many of the species he cites as changing to the 

 breeding dress without any renewal of the plumage. 



He says : " The change from the winter plumage to the breeding 

 dress without moulting is accomplished in three different ways. 

 The simplest of these consists in the shedding of the edges of the 

 feathers of the winter plumage." This he correctly describes, 

 citing numerous species in which it is exemplified, — ■ a change 

 well known to intelligent ornithologists the world over. The 

 second method, he says, " consists, so far as I have been able to 

 determine without the help of a microscope, in a peeling off of 

 the separate barbs of the feathers, whereby these are stripped of 

 a thin inconspicuously coloured envelope, so that the purer and 

 finer colour previously concealed beneath the latter becomes 

 exposed" (p. 152). In reality this is in part a less marked 

 wearing off of the edges of the feathers mentioned under his first 

 method of change, and in part a slight alteration of colour due to 

 the exposure of the plumage to the influence of the elements. 

 The " peeling " process is an original discovery of Herr Giitke, 

 and doubtless exists largely, if not solely, in his fertile imagination. 



" The last and most wonderful process in the colour changes of 

 the plumage of birds, not attended by a renewal of the feathers 

 themselves, consists in an actual, complete, and very striking 

 change in the colour of the feathers, without such alteration 

 being brought about, or even assisted, by any change in their 

 texture. As illustrating the climax of this process," he continues, 

 •• we may probably point to the change from pure snow-white to 

 an intense glossy black or blackish brown" (p. 153), as he avers 

 occurs in the head and neck of the Little Gull and in the fore-neck 

 and upper breast of the White and Pied Wagtails, and in the 

 heads and necks of Guillemots and Auks. The manner of this 

 change he describes with a minuteness that seems to bar all cavil 

 at its correctness, were it not for the utter improbability of the 

 case, and the known fact that in the same or allied American 

 species this spring change from white to black is due to moult and 

 a complete renewal of the plumage of the parts involved ! 



His remarks on the changes of colour in various species of 



