648 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



Family ANATIDiE. 

 Swan, Geese, and Ducks. 



A few words of comment upon the general subject will place it in 

 clearer light than that which the series of isolated remarks furnishes, and 

 render lengthy accounts of the several species unnecessary. During the 

 autumnal migration, vast bands of water-fowl enter Montana and Dakota 

 from the north. The nature of the country is such that the birds stop- 

 ping for rest and food necessarily come together in immense numbers ; 

 for superimposed upon their gregarious disposition is the circumstance 

 that the water supply is precarious or isolated, the country at large 

 wholly unsuited to their wants. The result is, that the most slender 

 streams, often mere threads, with scarcely strength to flow, or even 

 broken into chains of sloughs, and all the temporary water-holes formed 

 in depressions of the prairie, become thronged with the birds. This 

 gives an impression of extraordinary numbers of these birds, but it 

 should be recollected that we have here the percentage of birds due to 

 large areas concentrated in particular spots. Duck-shooting under these 

 circumstances becomes a somewhat special branch of the art. 



Another circumstance is, that the parallel of 49° is about on the edge 

 of the breeding ground of those species which regularly migrate north- 

 ward to breed. A large number of the Ducks, and some of the Geese, 

 as is well known, nest indiscriminately in any part of the United States; 

 but aside from these, all of which of course occur in the present country 

 as well as elsewhere, there are a number of species of truly boreal breed- 

 ers, which begin to drop deserters at about this latitude. As a result, 

 nearly all of the Ducks of l!forth America, except the maritime and 

 thoroughly Arctic oues, nest within our limits. They choose the ponds 

 and prairie sloughs, and the little pools in the mountains; and during 

 the latter part of the season, these places assume the appearance of a 

 farm-yard puddle, from the quantity of droppings and cast feathers. 



In general, throughout this Eeport, the tabular lists of specimens 

 afford a tolerably fair index to the abundance or scarcity of the several 

 species secured ; but this fails altogether in the cases of the birds of 

 this family, few of which seemed worth the trouble of preparing or the 

 expense of transportation, although large numbers were shot as legiti- 

 mate objects of sport or to vary our fare. 



CYGNUS BUCCINATOR, Eich. 



TmrMPETER Swan. 



Observed on a few occasions in Dakota late in Sej)tember and during 

 the tirst half of October, during the migration. It appears to pass 

 chiefly by night, but I saw a small lot flying in the daytime near Fort 

 Stevenson. The species is said to breed in the Yellowstone country, 

 and also iu Minnesota. 



