іоб 



Geese of Europe and Asia 



Adult Birds 



Head and neck grey-brown, for the most part with strong rufous, coffee, or grey-bay 

 tint. A male from Amurland, 1 figured in the plate, has even a golden-buff colour on the head 

 and neck, and apparently such examples are far from being of rare occurrence locally in East 



Siberia, as indicated by the name, 

 ^ — " yellow - headed goose," met with 



among native appellations in Trans- 

 baikalia. All these various tints 

 are evidently of accidental origin, 

 and are just as often present in 

 different individuals as absent. 

 They are doubtless caused by the 

 same factors as the rusty or yellow 

 tinges on the heads of swans, ducks, 

 and other species of geese. 



Sometimes this secondary 

 colouring is limited to the head 

 alone, or to the head and neck, but 

 in other cases, although less often, 

 it extends more or less regularly 

 to various parts of the plumage of 

 the body. Owing to the kindness 

 of Professor M. A. Menzbier, I was 

 able to examine an example of M. 

 arvensis in his collection, obtained 

 in the Moscow Government, which has a rufous tinge on the head and, here and there, 

 on the neck and body, and in which the feathering embracing the base of the bill is 

 bright rusty colour. 



In the rest of the plumage, except for a more uniform dark brown colouring on 

 the upper surface of the body (which again must be verified by a large number of 

 specimens), the eastern form does not differ from the type. Even in dimensions, with 

 the exception, of course, of the bill and feet, M. arvensis sibiricus almost agrees with 

 large examples of M. arvensis, and, it would seem, also in weight rarely exceeds them. 

 In absolutely all the specimens I have examined the yellow colouring of the bill was 

 concentrated on its apical part, forming a ring round both mandibles, and beginning 

 immediately behind the nail of the upper mandible. The breadth of this ring is some- 

 what variable, and occasionally very small, as, for example, in the specimens figured by 

 Middendorff {Sib. R., pi. xx. fig. i) and by Khomyakov {Pt. Ryazansk. g., pi. ii. P- 3)> 

 and only occasionally does the yellow-orange colouring of this ring reach back to the 

 anterior edge of the nasal depressions. Indeed, I do not know a single instance of the 

 yellow colouring from this ring projecting in a wedge backwards under the nares or 

 along the edge of the upper mandible, as is always the case in the yellow-billed goose, 

 after the second year. The whole of the remainder of the bill in the Siberian goose is 

 black. Although I have already mentioned the fact elsewhere, I deem it not superfluous 



1 Obtained by G. T. Radde, and now in the British Museum. 



M. arvensis, £ 

 Culmen 66 mm. 

 (Central Russia.) 



M. arvensis sibiricus, $ 

 Culmen 82 mm. 

 (Transbaikalia.) 



