1SS4.J Henshaw on t/ic North American Sliorc /.arks. '^'^^ 



tory, they necessarily have received frequent inention at the 

 hands of authors and have, indeed, figured in ahnost every local 

 bird list that has appeared. It needs but a glance at them to 

 reveal the extreme uncertainty that has always attended their 

 identification, uncertainty almost as marked in the notices of 

 experts as of authors of less scientific pretensions. It has long 

 been evident to those who have paid any attention to these birds 

 that the present arrangement fails to meet the necessities of the 

 case, and that either a number of new forms must be recognized 

 or else that the characters of the forms already described must be 

 extended so as to cover the peculiarities presented by a large 

 number of specimens which by anything like a literal interpreta- 

 tion of published diagnoses cannot be assigned at all. In other 

 words, it is clear that the existing arrangement does not permit 

 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 practical!}^ perma- 

 nent conditions, or owing to the possession of an unusually plas- 

 tic organization, the Horned 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 suificient 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 



