A REVIEW OF THE LARKS OF THE GENUS OTOCORIS. 
By Harry C. Oberholser, 
Asslskdit OrnitJto/o'/i.st, Department of A/jriraltare. 
Among' all the many and vaiiou,'? groups of l)irds which have in 
recent years of ornithological activity become noted as conspicuous 
exponents of extreme geographical variation, none is more prominent 
than that comprising the horned larks. Possessed of an extremely 
plastic organization, and subjected to comparatively stationar^^ condi- 
tions, these birds have responded to environment and other influential 
circumstances to a degree that has invested them with peculiar interest 
and instructiveness for the philosophical student, and at the same time 
has rendered their classitication and identitication a source of despair 
to the s3stemtitist. But the manner and degree of variation must be 
properly set forth before the full significance of these facts can be 
appreciated, and this should be the ultimate aim of systematic research 
— not, as seems only too often to l)e so considered, the mere facilitation 
of the determination of specimens in the cabinet. 
With the few exception>< of cases in which the forms appear to be 
trenchantly defined, all of the horned larks, both Old World and 
American, grade insensibly into some other, often into several, so that 
with all the connecting links represented it frequently becomes a mat- 
ter of considerable difiiculty satisfactorily to segregate the forms 
represented by such series. If, however, it be remembered what an 
adaptability to both climate and physiographical conditions these ))irds 
possess, the fact of their great geographical \ariation seems hardly so 
surprising. Thej^ are found from the shores of the Arctic Ocean to 
the heart of the Tropics; from the level of the sea to the summits of 
lofty mountains, and from regions of excessive rainfall to the most 
arid deserts. The}" are preeminently birds of the open country, rarel}^ 
if ever, venturing into the depths of the forests, for the grassy savan- 
nas, cultivated fields, country roadsides, the bare or brushy deserts, 
and the stony mountain slopes are habitats much more to their taste. 
The largely graminivorous nature of their food has undoubtedly nuich 
to do with th<?ir being so nearl}' resident, a condition that seems to 
exist (juite generalh^ throughout the genus. The northern forms, 
Proceedings U. S. National Museum, Vol. XXIV— No. 1271. 
Proc. N. M. vol. xxiv— 01— 51 801 
