266 The Great Auk. [Sess. 1896-97. 



Comparison — Plates I., II., and III. 



Plate I. This is a reproduction from a photograph of the 

 youngest specimen of the Great Auk {Aha impennis Linn.) 

 that is known. This appears to be the general opinion of 

 naturalists. It is, however, very remarkable that the white 

 mark on the plumage of the side of the head in front of 

 the eye, which appears in all adult specimens, is also appear- 

 ing on this young bird, while on that in Plate II., which 

 is generally assumed to be a Great Auk, and the older bird 

 of the two, the white mark is absent. The remainder of the 

 plumage of the Plate II. specimen, however, gives one the 

 impression that it is the older, as there is a more clearly 

 defined line between the dark plumage of the back and the 

 light plumage of the front of the body. The plumage of the 

 back is also less speckled than in the No. 1 specimen, and 

 has a closer approach to the plumage on the back of the 

 adult bird. The breast of the bird figured on Plate I. is 

 spotted and mottled ; that on Plate II. is more spotted and 

 less mottled than Plate I. The specimen on Plate III. is 

 probably the third youngest specimen known, and has still 

 some spotted plumage about its head and the front of its 

 neck. The small size and general appearance of this speci- 

 men lead one to infer that it is immature. It is exceedingly 

 interesting, and it is unfortunate that we know so little about 

 its history. 



