208 
IMMEE GOOSE. 
actual observation, intended to account for what seemed to 
be difficult. And it does appear surprising, that the only 
supposition which obviously resolves or precludes these ob- 
scurities, should not have at once presented itself to minds 
in the least degree habituated, not indeed to closet, but 
practical ornithology. 
In prosecuting this interesting branch of natural history, 
I was soon struck with the unsatisfactory and obscure opi- 
nions generally entertained regarding many species of the 
Colymbus genus, and more especially the Immer ; and I 
early embraced the opinion, that this bird was merely the 
young of the Great Northern Diver : but I determined to 
confirm this by patient observation, and particularly by con- 
trasting the two birds together, and it was not long before 
this opportunity was afforded me ; it has since been fre- 
quently repeated, and has left no doubt on my mind of the 
accuracy of the opinion I had first formed. 
The Immer is found during the whole year in Zetland, 
though in summer it is rather less numerous, and at this 
season it is most frequently met with in single individuals. 
Its nest has never been discovered, nor has its young been 
observed accompanying it. Its size and plumage in different 
individuals are various ; its organs of generation indistinct. 
These facts, taken in connection, prove, I think, this 
bird to be not yet arrived at an adult state ; and they agree 
perfectly with its general description by naturalists. 
That it is the young of the Northern Diver, is, I con- 
ceive, equally established in every respect. 
I have examined specimens in all the different gradations 
of plumage, from the more imperfect appearance of the 
Immer till it had almost attained the beautiful and well- 
marked plumage of the C. glacialis. These specimens, ap- 
parently just passing into the adult state, were mostly ob- 
served during summer, and too early in the season to sup- 
