804 THE POPULAR SCIENCE MONTHLY. 



It had long been observed that, as the sun conies to our side of the 

 equator, the buds swell, the leaves and flowers unfold, and a sheet of 

 verdure expands and spreads toward the pole ; and closely following 

 this there comes a mighty army of bird-life — orioles, tanagers, and 

 warblers of brightest hue — filling every orchard, grove, and wood- 

 land with life, and song, and joy. And again, when autumn comes, 

 the wave returns to us from the North, bringing with it the black 

 snow-birds and other species which make their winter home with us, 

 while the great bulk of the species pass on to the southward as mys- 

 teriously as they came. 



The flight of storks has given trouble to the Germans and the Chi- 

 nese, while the disappearance and the reappearance of the swallows 

 have caused untold trouble everywhere. Learned bodies, like the 

 French Academy and the Royal Society of London, have gravely as- 

 serted that, in the fall, swallows plunge into the mud of marshes and 

 mill-ponds, become torpid, and hibernate like frogs and snakes. I 

 have seen a list of nearly two hundred articles written all along from 

 the middle of the seventeenth century down to 1877, for the purpose 

 of proving or disproving the hibernation of swallows and other birds ! 

 And Dr. Coues says he can lay his hand upon papers of that period 

 which discuss the migration of swallows to the moon, the falling of 

 the little quadrupeds called lemmings in showers from the clouds, and 

 the origin of brant-geese from barnacles that grew on trees. Indeed, 

 not a year ago I was assured by a gentleman of more than average in- 

 telligence that this last is undoubtedly the correct theory as to the 

 origin of the barnacle-goose ! And it was not a decade ago that I 

 read, in one of the leading newspapers of this State, an article of as 

 curious a character. Its purpose was to explain the sudden appearance 

 in fall of the black snow-birds, and their as sudden disappearance in 

 spring, and the explanation given was that our common sparrows 

 change color in fall, becoming snow-birds, which they remain until 

 spring, when they put on their other dress and become sparrows 

 again ! And I find that, among the common people of the country, 

 there are many who have this belief. 



We have long known in a general way that the birds go south- 

 ward to winter, and return to spend the summer at the North. But 

 just where in the South do they go? Why do they go there? By 

 what routes do they travel ? At what rate of speed ? Do they travel 

 by night, or day, or both ? What species migrate first, which last, 

 and why ? How are they guided in their course ? What is the win- 

 ter as well as the summer habitat of each particular species, when 

 does it get there, and when does it leave the one for the other? In 

 what way and to what extent are their movements dependent upon or 

 influenced by vegetable and meteorological phenomena ? 



These are but a few of the questions which ornithologists have 

 sought in various ways to answer. The limits of this paper will per- 



