je6;ure: but it is a cor4je£i:ure which derives fupport from many interefling fadls which I have collefled, and which 
will be mentioned and explained in my Geographical View of the Trees and Shrubs of Norih-Amcrica. In that work, 
I fliall fhow, that the fouthern trees and fhrubs (that is, thofe vegetables which attain to their greatefl perfeciion in 
the fouthern climates of our continent, particularly of the United-States) are, in general, found much farther 
north in the weftern than they are in the eaflern parts of our country. This fadt feems to fhow, and the point is 
put beyond any manner of doubt, by thermometrical obfervations, that the weftern climate, in the fame lati¬ 
tudes, is more temperate than the eaflern. Of courfe, it were natural to fuppofe, that the fouthern birds, to whom 
heat is fo genial, would often be folicited farther north in the weftern than in the eaflern diflrict. This, with refpedt 
to fome birds, is actually the cafe. Mr. Jefferfon has obferved, that Perroquets even winter on the Sioto, in the 
39th degree of latitude.”"*^ I have certain information, that thefe birds winter ftill farther north than is here mentioned. 
§. IX. 
. Birds, in migrating, are fond of following the courfes of rivers, and other large flreams of water. This circum- 
ftance, in my opinion, partly explains the reafon, why fome of the birds of the fouthern parts of the United-States, 
and alfo fome of the South-American birds, which have never, or very rarely, been difcovered in the Atlantic coun¬ 
tries of North-America, are not uncommon in the countries weft of the Alledianev-Mountains. Thefe fouthern 
birds, following the courfes of the Miffiffippi, and its branches (the Ohio, the Illinois, &c.) are fpread or difperfed 
through the rich and extenfive territories that are wafhed by thefe waters. Whether or not this explanation be 
admitted, the fadl is certainly as I have flated; and to the naturalifi: it cannot but appear interefling. The Pfittacus 
pertinax is one of the birds of Brafil; and the Mufcicapa Tyrannus, which is held in fo much efleem by the Nau- 
dowcflies, and other weftern Indian tribes, is a native of Surinam, and of the country bordering on the river Plata. 
§. X. 
It is, I think, in general, a juft obfervation, that our Spring and Summer birds of paflage continue with us 
about fix months, and are abfent for the fame length of time. Accordingly, thofe birds which arrive early in the 
fpring difappear early in the autumn, and thofe which arrive late in the fpring do not difappear until late in the au¬ 
tumn. Our late fprings are commonly fucceeded by late and warm autumns, which, by keeping alive the numerous 
fpecies of infedls, which are the favourite food of almoft all our fummer birds of paflage, detain thefe birds for a 
confiderable time among us. 
§. XL 
The greater number of the Spring and Summer birds of paflage, which I have mentioned, build and breed in 
Pennfylvania.t Perhaps, they all breed in fome part of this extenfive ftate, with the exception of the Vultur 
Aura (Turkey-Buzzard), and a few others, which do not vifit us until towards the clofe of the fummer. It has lately 
been afcertained, that the Ampelis Garrulus, or Prib-Chatterer (Cedar-Bird) does breed in Pennfylvania; and I 
doubt not, that the fame will, in time, be difcovered to be the cafe with the Emberiza Oryzivora (Rice-Bird, 
Reed-Bird), and others whofe nefts have not hitherto been feen in Pennfylvania. It is not unlikely, however, that 
fome of thefe birds of paflfage continue their migration farther northward, to New-York, New-England, Vermont, 
&c. and there breed and raife their young, returning fouthward, through Pennfylvania, in the fall. 
§. XII. 
It is an interefling fad, for which we are indebted to Mr. William Bartram, that very few of our birds of paflage 
from the fouth build or rear their young in the fouth or maritime parts of Virginia and Carolina, Georgia and 
* Notes on the State of Virginia. Page 139. The original edition. 
t See Appendix I. where I have defignated with an aflerilk (*) thofe birds which are hewn to breed In Pennfylvania. The greater number of them thus marked 
breed ■within a few miles of Philadelphia. 
