Reproduction 35 
in Oregon) ; bleak and barren . . . plains (Batchelder, 1885, 
O. a. chrysolaema in New Mexico) ; in park-like openings in the 
mountain forests up to an altitude of 10,000 feet (Mearns, 1890, 
O. a. adusta in Arizona) ; on bleakest and most exposed hillsides 
(Bigelow, 1902, O. a. alpestris in Labrador); on prairies, in 
denser vegetation than O. a. praticola (Criddle, 1917, O. a 
enthymia in Manitoba). 
In summary of these accounts three or four things are to be 
pointed out: (1) the Prairie Horned Lark selects the bleakest 
barrens available in every locality in which to nest. These may 
become weed grown during the nesting but the optimum condi- 
tion, the criterion of the Lark’s choice, is the condition of these 
localities when the site is selected and the nest built; (2) the 
“‘barren’’ condition is, apparently, that which possesses little 
or no verdure. Moisture, elevations, nature of soil, are all sub- 
servient to that one requirement—bare ground; (3) from the 
close-cropped pasture (an ideal ‘‘barren’’ in March), the Larks 
are driven by press of verdure in May; then they select the last 
bare ground available—the gardens, the cultivated fields; (4) all 
other subspecies of the Horned Lark seem to resemble the Prairie 
Horned Lark in their selection of nesting sites though 0. a. 
praticola, exceedingly versatile, has invaded those ‘‘barrens 
that civilized man so artificially creates. 
The breeding territory at Evanston—About one and one- 
half miles from the west limits of the city of Evanston, Illinois, 
and about two and one-half miles north of the north bounds of 
Chicago, lies the bit of territory which was worked most thor- 
oughly in this study. This, like many hundreds of acres on all 
sides of it, was, until a few years ago, an extensive marsh. At 
that time it was, manifestly, unsuited as breeding grounds for 
the Prairie Horned Lark. 
Portions of this marshy area were, with difficulty, put under 
cultivation after a drainage canal had partially removed the 
water, but much remained unutilized and weed-grown. That 
area, which later became what is called the ‘‘Main Subdivision”’ 
in this paper, was one of these weed-grown regions and a smaller 
area just west, here called the ‘‘ West Subdivision’, was put into 
gardens. Here it is well to call attention to the fact that, though 
the Larks might have nested in the gardens of the West Sub- 
division, they could not have nested in the Main Subdivision 
