Summary 129 
such an extension is bona fide. It is suggested that this exten- 
sion of range has resulted from changes which civilized man has 
made by deforestration and cultivation; thus creating perma- 
nent, or seasonally semi-barren, conditions which the Prairie 
Horned Lark required. 
B. Primitive range. It is noted that the dryer portions of the 
prairies of Illinois have probably long been occupied by this 
ark. The studies of Forbes and Gross seem to indicate that 
the Lark, though it probably breeds in Lower Austral, Upper 
Austral and Transition Zones, seems to prefer the Transition in 
that state. It is suggested that the prairies of northern Mis- 
souri, Iowa, Wisconsin, Minnesota, eastern portions of Kansas, 
Nebraska, North and South Dakota and southern Manitoba, 
probably formed the ancestral home of the subspecies. Nearly 
all of this vast region would have been suitable for two broods 
in March, April and early May, though the bird would have 
been foreed to the more barren regions as the grasses became 
vigorous in late May, June and July. That this Lark species 
is versatile in the matter of occupation of new territory seems 
to be further demonstrated by the observations of Gatke and 
Saunders in Europe with regard to 0. a. flava. 
II. Migration. 
A. General. Subspecies of the Horned Lark vary from 
Strictly sedentary forms to others which leave their breeding 
range entirely and for long periods, and therefore are quite 
highly migratory. The Prairie Horned Lark, in migratory 
habits, lies between these extremes. This bird breeds north to 
the southern edge of Canada, migrates south to South Carolina, 
Kentucky and Texas. From the northern part of this range it 
is absent during the month of December and part or all of 
January. Throughout the remainder of the breeding range some 
indivjduals will be always present. 
B. Migration of sexes and individuals. Insufficient data on 
this subject seem to indicate that resident adult males arrive 
first on the breeding ground, next resident adult females, next 
transient males and females and lastly vagrants and immature. 
III. The Lark in Autumn and in Winter. 
Flocking. Young Larks flock shortly after nest leaving. 
— the breeding ground has become untenable due to vegetation 
