112 BIEDS OF ILLINOIS. 



consider this as at all probable, although in view of their sim- 

 ilarity of form and size, and the fact that the chief variations 

 are a tendency toward partial albinism, the possibility of such 

 a relationship should be borne in mind. 



A specimen figured in the ''Transactions" of the Chicago 

 Academy of Sciences, Vol. I., 1869, pi. 18, has the whole under 

 parts, posterior to the chest, pure white. We have also seen 

 examples in which not only the abdomen, but also the rump, 

 was white ; while, as noted above, white feathers are sometimes 

 interspersed irregularly in the dark plumage of the body. There 

 is also something very "unsatisfactory" or suspicious in the 

 irregular, variable, and undecided way in which the white of the 

 neck joins upon the dark color below it. 



Mr. E. W. Nelson, of Chicago, who has enjoyed the advantage 

 of inspecting very numerous specimens in the markets of that 

 great game center, writes as follows (Butt. Nutt. Orn. Club, 

 VIII., 1876, p. 137) with regard to the changes of plumage in 

 this species: 



"The adults of this species invariably possess the white head 

 and upper part of the neck, which in the younger specimens is 

 more or less variegated with dark feathers. These disappear as 

 the bird becomes older; and in many the head is a pure snowy 

 white, in sharp contrast to the dark plumage of the rest of the 

 upper parts. The young would appear at first sight to be a 

 distinct species, so different is the pattern of coloration. The 

 white of the head, neck, abdomen, and tail-coverts is entirely 

 absent, and the bird is of an almost uniform ashy plumbeous, 

 slightly darker about the head, and lighter on the abdomen. 

 This plumage is retained until the second year at least, as many 

 specimens are procured in the spring with the dark head, neck 

 and abdomen still immaculate ; and these, I think, are young of 

 the preceding year. At the same time specimens are found with 

 the dark feathers about the head well mixed with white, repre- 

 senting the second year. In birds of the third year the white 

 predominates; but not until the fourth or fifth year does the 

 plumage become perfect." 



The Blue Goose is a common species in Illinois during the 

 migrations, sometimes mixed in with flocks of the Snow Goose, 

 but often in flocks composed entirely of its own species. In his 



