Summary 131 
be tolerated, in the selection of nest sites. The Prairie Horned 
Lark does not differ greatly in the ecological condition of breed- 
ing habitats from other Horned Lark subspecies. 
2. The breeding territory at Evanston, Illinois. Some typical 
Chicago marsh, in the Evanston region, was drained for a golf 
course. The golf course was later cut up into real estate sub- 
divisions ; sewers were laid exposing a wide area of bare soil in 
the streetways; old sand hazards remained here and there. This 
Series of activities provided nesting sites for many Larks. More 
than a score of nests were located on this area (about 90 acres) 
in 1926. 
A plot of vegetable gardens, bordering the region noted above 
on the west (where Larks probably had nested for some years), 
was also subdivided and the vegetation subsequently neglected. 
Here several Larks also nested. 
The advent of vegetation in both areas and the demand of 
the Lark for bare ground, forced a seasonal succession of Horned 
Lark breeding sites first from lot surface, to streetway, to sand 
hazard, to vegetable garden, in the order that each was succes- 
Sively occupied by verdure. 
3. The breeding territory at Ithaca, New York. One nest was 
located on the overturned sod of a former hay meadow. Most 
of the observations were made on a tract of ground that was 
largely fall wheat, partly fall rye, and the remainder devoted to 
experimental vegetable gardens. The growth of the fall wheat 
forced the Larks from its surface by late May. The gardens, 
and portions of the fall rye area which were turned under as 
green manure, remained suitable throughout. Clean vegetable 
gardens will always present a considerable amount of bare soil 
and the Prairie Horned Lark is usually able to occupy them 
until late June. 
B. Song. 
1. Season of song. Extended, in the Evanston region, from 
mid-January until early July; in the Ithaca region, from mid- 
February to late June. 
2. Monthly variations in song numbers. Using flight songs 
for a criterion, it was found that May was the optimum month. 
The Lark sings, both from the ground and in the air, under all 
conditions of weather, though flight songs are most numerous On 
