Migrations of North American Birds. 185. 
there by way ‘of the Platte, those of Washington Territory by 
both the Platte and upper Missouri. 
Although thus extending westward, almost, if not quite, to 
the Pacific, along the northern boundary, they appear to always 
return the way they went as none of the species have yet been 
met with in California. 
I have added to each species the locality on the Missouri river 
up to which it was observed by Dr. Hayden in one of his early 
explorations. 
Species of Eastern birds found at Fort Bridger. 
Tyrannus Carolinensis, Fort Union and Yellowstone. 
Turdus fuscescens, 
T. Swainsoni, 
Seiurus Noveboracensis, 
Dendroica coronata,? 
Setophaga ruticilla, Fort Pierre. 
Vireo olivaceus, “ Union (Mr. Audubon). 
Mimus Carolinensis, “ Lookout. 
Zonotrichia leucophrys, (not found farther west). 
Quiscalus versicolor, Fort Benton (Pearsall). 
It will be sufficiently evident, as most birds change their resi- 
dence from winter to summer, and vice versa, that unless we de- 
vote especial attention to their distribution during the breeding 
Season, we shall not be able to mark their boundaries with pre- 
“sion. Species which go north to the Arctic circle to nest, re- 
turn to mix in Mexico, Guatemala, or the West Indies, with 
Species resident in those countries, or of short migration, and are 
followed part way in their southern flight by Arctic birds start- 
ing from localities still farther north. The case is quite different 
with reptiles, and most insects and mammals, of which a few spe- 
cles only change their residence or leave their place of birth, 
Not in obedience to the instinct of reproduction, but of necessit, 
seen 
arch of a suitable place to deposit their spawn, which takes 
with the same regularity as to date and direction that we 
in birds, : 
It is only of late years that we have been enabled to determine, 
Teach Mexico and Guatemala, and the number of thse passing — 
farther south diminishes with the latitude. Very few of the 
land birds pass into South America, the following being a list of 
oS ? Found by Dr. Suckley on Puget Sound. 
Ax. Jour. Scr.—Szcoxp pretend Vor. XLI, No. 122.—Manci, 1866. 
