274 FACULTIES OF BIRDS. 



than that of pigeons, and talked of nothing 1 but 

 pigeons. The atmosphere, during this time, was 

 strongly impregnated with the peculiar odour which 

 emanates from the species." 



Captain Flinders relates a somewhat parallel in- 

 stance ; he says that while on his voyage he saw u a 

 stream of stormy petrels, which was from fifty to 

 eighty yards deep and three hundred yards, or more, 

 broad. The birds were not scattered, but flying as 

 compactly as the full movement of their wings seemed 

 to allow ; and this stream of petrels for a full hour 

 and a half continued to pass without intermission, 

 at a rate little inferior to the swiftness of a pigeon. 

 Now taking the stratum at fifty yards deep by three 

 hundred in breadth, and that it moved at thirty miles 

 an hour, and allowing nine cubic inches of space to 

 each bird, the number would amount to one hundred 

 and fifty-one millions and a half." 



Among these irregularly migratory birds, one of 

 the most remarkable is the wild turkey, which shifts 

 about from one district to another, according to the 

 comparative abundance of the natural fruits. The 

 continent of North America, on account of its great 

 extent from north to south, and the comparative faci- 

 lity of making observations in the different states and 

 provinces, affords an excellent field for studying the 

 partial migrations of birds, some of which have been 

 detailed by Wilson and Audubon. 



The blue-bird of America seems to have a power 

 of continuous flight almost equal to that of the swal- 

 low, and among the most interesting of established 

 facts on the subject of migration is that which makes 

 it necessary that this small bird should pass at least 

 six hundred miles over the sea. Wilson says, " No- 

 thing is more common in Pennsylvania than to see 

 large flocks of these birds, in spring and fall, passing 

 at considerable heights in the air, from the south in 



