198 NOTES AND NESTING HABITS OF BIRDS. 
brown thrasher (Harporhynchus rufus) also sings more vigorously 
in the latter locality.: In the far west I found the ground robins 
of the Wahsatch Mountains (Pipilo ‘‘ megalonyx”) to have such 
different notes from those of the eastern slope of the Sierra Ne- 
vada (in the neighborhood of Carson City) that it seemed that 
they must certainly be a different species ; not only did the song 
differ, but all the notes were different. Yet upon the closest com- 
parison of the specimens, no tangible differences in plumage or 
proportions could be detected in the majority of the specimens 
from the two localities, though occasional individuals from the 
latter place inclined, more or less, toward the form known as P. 
egonus. 
The exact nature of the difference in notes between certain - 
birds in the Potomac valley, and the valley ofthe lower Wabash, 
is a very marked restraint in the songs of the former, as if they 
were afraid of being heard. That they were more cautious in the . 
neighborhood of noisy cities, than in the country surrounding 
quiet and less populous towns, might be readily suggested asthe , 
solution of this difference, were it not for the fact that other spe 
cies, as, for instance, the robin (Turdus migr atorius), the mead- - 
ow lark (Sturnella magna), the catbird ( Galeoscoptes Carolinensis), — 
the Thryothorus Ludovicianus and numerous other species, sing aS 
boldly and in a precisely similar way among the parks and shade 
trees in the midst of Washington City as they do in the quiet 
towns and retired orchards of southern Illinois. This objection 
may ‘lose weight, however, when we consider that the species iD 
which I have noticed a difference are birds of. a suspicious and i a 
cautious nature, such as would be most readily influenced by the 
causes mentioned. . a 
‘Mr. Allen has called attention* to variations in the incite of : 
nesting, which he has noticed in many species of birds; and - 
places undue importance upon it in considering certain deviations 
from the usual manner as characteristic of particular localities. = 
_ My experience has been that such variations depend mainly upor 
the facilities afforded by the site of the location of the nest, and 
‘sometimes, no doubt, are the result of merely the caprice of the 
bird. The Quiscalus purpureus is cited as one example, and con- 
‘siderable stress is laid upon the fact of its placing the nest n 
peine of trees in a certain locality in New England. At Mt 
* See AMERICAN NATURALIST, VOl. Vi, p- 263. a 
