36 Trans. Acad. Sci. of St. Louis 
until the time of the changes about to be related. That they 
came onto this area in great numbers within two years after its 
conversion is but another evidence of the striking versatility of 
the Prairie Horned Lark in acquiring new breeding territory. 
The weed-grown condition of the one area remained unmodi- 
fied until 1923 or 1924, at which time the entire surface, very 
flat previously, was altered to form a golf course. Drainage was 
completed, artificial hazards created, bunkers, greens established, 
mounds were thrown up here and there. Though the area was 
not under close observation at that time it is quite possible that 
a few Larks may have nested on the margins of the sand hazards 
as they do on many golf courses in their range. 
The golf course was short-lived. In the fall of 1924 a branch 
of the Chicago Elevated Railroad penetrated to the vicinity. 
Promptly the erstwhile golf course was subdivided; sidewalks 
stretched themselves out over night, whirling lot-sale signs clat- 
tered everywhere and those indefatigable, hopeful pillars of 
progress, the street sign posts, soon stood like solitary glistening 
martinets on the otherwise uninterrupted landscape. 
But this, the Main Subdivision, became a paradise to the 
Prairie Horned Lark. In the spring of 1925 the grass of the 
former course was burned off and the whole subdivision pre- 
sented a blank, black, almost smoothly denuded face. Here the 
Lark was at home. Even in June, in areas in which vegetation 
came on slowly because of scraping or sanding for former 
hazards, nesting was still in progress. During the summer of 
1925 sewers were laid in the street-ways, north and south, and 
this activity threw up a mound of dirt thirty to forty feet wide 
in the center of the street, a strip that grew no verdure until 
late summer, 1926. And so, at its edge, in the thin grass strip 
between it and the sidewalk there were provided sites for fifteen 
located nests of the Prairie Horned Lark (see Fig. 9; Plate III, 
Fig. 1; Plate XII, Fig. 1; Plate XIII, Figs. 1 and 2), during 
1926. 
In 1926 the Main Subdivision began the nesting season with 
closely clipped, dread grass of Agrostis palustris (red-top), and 
Poa pratensis (blue grass), with here and there, in old hazar 
coarse stems of dead thistle (Cirsium arvense), primrose (Oend- 
thera biennis), ragweed (Ambrosia artemisiaefolia), white, sweet 
clover (Melilotus alba). Much of the ground though, was bare ~ 
