1884.] 
Henshaw on the North American Shore hark 
2 55 
tory, they necessarily have received frequent mention at the 
hands of authors and have, indeed, figured in almost every local 
bird list that has appeared. It needs but a glance at them m 
isaiuiiuisi ivji [juuud.i..,.., .. ^ icacnea its aes- 
tination, having probably been lost in the mails. The specimen 
vas.mofl tmn afterward. and T am therefore without memo- 
J 
conspicuously from any plumage of B. borealis in having the 
the facts of geographical variation, of which this bird is a most 
conspicuous illustration, to be recognized and expressed. Of the 
two alternatives, the former appears to the writer to be the log- 
ical and proper course. 
The causes for the extreme variation witnessed in this species 
are not far to seek. Like several other birds, notably the Song 
Sparrow, which split up into a number of geographical races, the 
Shore Larks are to a great extent resident wherever they occur, 
and, although individually they are by no means local, but 
wander far and wide for a considerable portion of the year, 
their movements do not carry them far enough, or last sufficiently 
long, to subject them to any considerable changes of food or 
climate. As the result of being subjected to practically perma- 
nent conditions, or owing to the possession of an unusually plas- 
tic organization, the hlorned Lark varies with locality to an 
extent unprecedented among our birds, even the Song Sparrow, 
hitherto supposed to illustrate the extreme degree of susceptibility 
to geographical changes, falling behind in this particular. 
Although not, strictly speaking, migratory, the extent to which 
the Horned Larks change locality is sufficient to materially com- 
plicate the geographical relations of the several forms. Over 
much of the west coast, and in almost all the southern part of the 
United States, these birds can scarcely be said to migrate at all, 
although they may, and doubtless frequently do, wander in win- 
ter from the localities which form their abode' the greater part of 
the. year. In the more northern parts of the United States, and 
