90 On the Migration of North American Birds. 



that the ground was not covered with snow. It is only when the 

 forests of the west have failed in their usual supply of mast and ber- 

 ries, that the wild pigeons come among us, to claim a share of the 

 acorns and berries of our w^oods, and the refuse grains scattered over 

 our rice fields. 



It is, perhaps, not improbable, that the occasional changes in the 

 migrations of the birds of our continent, may, in the course of time, 

 introduce among us some species of birds from the south and west, 

 that are not now found here. A large number of the feathered race 

 follow the improvements of civilized man. No sooner does cultiva- 

 tion commence, than many birds, which were unknown in the forest 

 around him, are seen in his fields and orchards. A new species of 

 grain attracts the graminivorous bird — a particular plant or tree, on 

 which certain caterpillars or insects feed, invites the Sylvias, Vireas, 

 and Muscicapas ; and the tubular flowered plants of the West Indies, 

 transplanted into the soil of Florida, are already beginning to attract 

 some of the many species of humming birds of the south. In the 

 days of Wilson, (one of the most observing of our American orni- 

 thologists,) the great Carolina Wren, (Troglodytes Ludovicianus,) 

 and the pine creeping warbler, [Sylvia Finns,) together with several 

 other species that are now common in the northern states, (where I 

 sought for them for many years in vain,) were there unknown. They 

 have now extended their summer migrations, as far north, at least, 

 as Boston. The cliff swallow, [Hirundo Lunifrons, Say,) a Mexi- 

 can species, was first seen on the banks of the Ohio, in 1815. These 

 birds excited much interest, from the peculiar structure of their nests, 

 built of mud, and clustered together, resembling a bunch of gourds. 

 From year to year, they continued to increase and advance east- 

 wardly in their migrations, until they have now extended across the 

 continent, as far as Canada and Maine. The olive-sided flycatcher, 

 [Muscicapa Cooperii, Nutt.) has but recently made its appearance 

 in the north, and on the mountains of Virginia ; and in the latter 

 situations, the newly described Bewick Wren of Audubon, {Troglo- 

 dytes BewicJcii,) has supplanted all the other species of that genns. 

 The fork-tailed flycatcher, {3Iuscicapa savann, Bonap.) has, only 

 within a few years, commenced leaving the tropical wilds of Guiana, 

 and a few stray birds of that species are almost annually seen in the 

 middle states. The solitary flycat-^her, ( Vireo solitarius, Vieill.) 

 which was so rare with us ten or twelve years ago, that scarcely a 

 bird of that species could be found in a year, has of late become so 



