NO. 1271. HE VIEW OF THE HORNED LARKS— OBERHOLSER. 803 
These cases .are severally treated under their proper headings. That 
such a condition is brought about by the simple intergradation of two 
or more forms appears to be sometimes undoubtedly so; but this does 
not in every instance furnish a solution, and parallel evolution under 
peculiar environmental conditions presents a more tenable hypothesis. 
From this feature of the group it may readily be surmised that the 
identification of specimens without reg'ard to geography is, to say the 
least, lia])le to be difficult. Among the song sparrows the characters 
of the various races, though sometimes slight, are quite uniforni and 
constant; but in the horned larks the problem is often exceedingl}^ 
complicated l)y reason of sexual, seasonal, and local dili'erences, together 
with excessive individual variation. Various more or less perfect 
intermediates are very perplexing, and no means of determination can 
possibly be of value except the actual comparison of specimens, coupled 
with an accurate knowledge of the relative value of the proper differ- 
ential characters. Satisfactoril}- to present such information in printed 
diagnoses is manifestly out of the question, for characters that will 
serve to identify even t^^pical examples of some of the more closely 
allied forms are frequently almost impossible to express intelligibly 
on paper. Generally speaking, the females of the various races are 
distinguished from each other l)y characters quite similar to those of 
the males, when due allowance has been made for sexual differences, 
so that one diagnosis will answer for both. Except in cases of very 
sharply defined forms the 3'oung birds in first plumage are not certainly 
distinguisha])le, owing to the great range of individual variation. 
As Dr. Dwight has already stated,' the horned larks molt but once 
a 3'ear. This takes place usually about August, and thereafter, until 
into the winter, the birds continue in the blended plumage thus 
assumed, the upper surface more or less uniform, the 3 el low bright 
and deep, the black areas obscured by paler, and the breast often much 
streaked with dusk}'. Through the wearing away of the tips to the 
feathers the whole aspect of the l)ird becomes changed l)y s^jring or 
summer — the back becomes darker, the colors of the upper parts more 
sharph' contrasted, the yellow fades perceptibly, the Iffack areas 
become unclouded, and the breast loses its streaking. 
Although the aggregate amount of material (2,150 specimens) 
reviewed in the course of the present investigation has been but 
slightly greater than that at Dr. I) wight's disposal when ho treated 
the North American forms, yet a great deal of that now available 
consists of bivediiig specimens not examined by him, and has of 
course been indispensable to the proper understanding of the various 
races now recognized. Unfortunately, only a comparatively small 
number of Old World l)irds has been examined, though ah but four 
1 Auk, VII, April, 1890, p. 139. 
