492 ORNITHOLOGY. 



Ibrms are sufficiently easy to recognize in typical or extreme specimens, 

 but such constitute so small a proportion of the number usually em- 

 braced in collections, that if called upon to define these supposed races 

 by trenchant characters, it is very doubtful whether we could succeed to 

 our own satisfaction, while the concurrence of others could scarcely be 

 expected. This is especially the case with regard to the oregonus and 

 megalonyx ty]Des, both of which came under our observation in the field. 

 Judging from the specimens alone, of these two forms, we should not think 

 of recognizing two races in the series before us, for it is absolutely impossible 

 to distinguish certain specimens obtained in western Nevada from others 

 taken in Utah. But since the notes of the birds of the two localities were 

 so extremely dissimilar as to really astonish us upon the discovery of the 

 fact, we cannot ignore this difference between the birds of the two districts ; 

 this, therefore, is our reason for arranging their synonymy as above. 



In their manners and general appearance these western Ground Robins 

 call at once to mind the eastern Towhee (P. enjthrophthalmus), for they have 

 the same colors (with merely minor differences, not distinguishable at a 

 distance), the same flirting flight, while they are inseparably attached to 

 the most bushy localities. But in direct contrast to the familiar eastern 

 species, we found the western Towhee to be everywhere one of the very 

 shyest birds of the country. The notes, 'too, are most remarkably different, 

 since none of them are in the least attractive, but, on the contrary, simple 

 and rude almost in the extreme. 



The Oregon Ground Robin was found from Sacramento to the West 

 Humboldt Mountains, it being equally common on both sides of the Sierra 

 Nevada. Within the Great Basin, its range was strictly confined to the 

 valleys and connecting canons of the western depression, while it was 

 abundant in proportion to the proximity of a locality to the Sierra. In 

 sunnner it was generally distributed — that is, included the lower canons of 

 the mountains in its range, as well as the river-valleys ; but in winter, it 

 appeared to make a more or less extensive vertical migration, nearly, if not 

 quite, forsaking the mountain localities. At Sacramento, it frequented the 

 thickets around the border of fields in the outskirts of the city, in the same 

 places as those inhabited by the Yellow-breasted Chat and Song Sparrow 



