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EXTRACTS FROM THE FOREIGN PERIODICALS. 



ZOOLOGY.* 



1. On the Migrations of North American Birds, by the Rev. John 

 Bachman. — Migratory birds are admirably adapted for rapid and protracted 

 flight. Their light hollow feathers, their bones full of air-cells, their large lungs, 

 and the force of their wings, enable them to float a long time in the air with 

 little exertion. It has been ascertained that the Migratory Pigeon (Columba mi- 

 gratoria), and many species of Anatidce, fly at the rate of a mile and a half in a 

 minute. [[Some birds, and especially certain of the Hirundinidce and Falco- 

 nidce, are supposed to fly occasionally at nearly four times this speed. — Ed.] — 

 Thus these birds can, in a single day, travel from Charleston to the northern- 

 most parts of the U. S., at once explaining the fact of Pigeons having been killed 

 in the northern states with undigested rice in their gizzards, which they had 

 swallowed, the preceding day, in Carolina or Georgia. A Falcon sent out by 

 the Duke of Lerne, has returned from Spain to Teneriffe, a distance of 750 

 miles, in 16 hours. 



It is certain that many birds of passage fly during the night; they first ascend 

 in the air, from whence they send forth their cries, and many, as the Stork, seem 

 scarcely to rest on their course from their winter quarters in the south to their 

 breeding places, towards the polar regions. 



Birds emigrate either to avoid the cold of winter, or, probably, to obtain food 

 more suitable and more abundant. t In fact, among those which remain in the 

 snows of the north, some are omnivorous (as Corvus corax, C. Canadensis, and 

 other Crows), while others feed on the buds or leaves of trees, as the Pine Thick- 

 bill, &c. But the insectivorous species, those which frequent marshes and stag- 

 nant waters, the borders of rivers, &c, all emigrate, and go to seek in the south 

 the kind of food they require. Some birds only migrate from the south to the 

 north of the Union, and do not proceed further than Carolina ; such are the 

 various insessorial birds, as Larks, &c. When the winter birds return to the 

 northern regions, they are replaced by analogous species from the tropics. Thus 

 in America the White-headed Elanus (Elanns leucocephalus), the Mississipi Fal- 

 con, and others, build in the woods abandoned by the northern raptorial birds, 

 so that each season brings a succession of different species. 



* As this is the first ornithological extract we have made from the foreign journals in the pre- 

 sent volume, we feel assured that no apology is necessary for quoting at such length from the very 

 interesting paper of Mr. Bachman. The article originally appeared in the American Journal of 

 Science; but our quotation is tianslated from a French periodical. — Ed. 



f These, doubtless, are the circumstances for which birds are caused to migrate ; but it must 

 be remembered that birds are impelled to change their abodes at certain seasons by a mere blind 

 impulse— an innate faculty, which is stimulated at those povods, and without any reason or 

 knowledge on their part of the cause of these emigrations.— Ed. 



