Ecology of the Nesting-Site 119 
Of all resident birds of the subdivisions the Vesper Sparrow 
is nearest the Prairie Horned Lark ecologically. The above nest 
was in an old hazard depression of bare ground chiefly, with 
scattered tufts of squirrel tail grass (Hordeum jubatum), and 
red top grass (Agrostis palustris), the only verdure. The nest 
itself was built partially under a little pile of old dead and 
dried weed stems. The Vesper Sparrow thus occupies the 
Sparse weedy regions, regions with trash and much bare ground, 
the nearest approach to the nearly bare open where the Prairie 
Horned Lark nests are found. Thus in the series the Vesper 
Sparrow comes in the second ecological breeding niche that 
starts with the Prairie Horned Lark in the barest of habitats 
and reaches to the Dicksissel in the densest. Another viewpoint 
is of great interest in this connection, in that the locations of 
the ecological niche for both of these birds varied with the sea- 
son. By late June the last breeding areas of the Main Subdi- 
vision had, with the press of summer verdure, become inhos- 
pitable to the Lark and the birds that were still breeding were 
in the more suitable ground of the West Subdivision. For a 
while longer the Vesper Sparrow remained in the Main Sub- 
division but July found it following the Lark—two weeks of 
plant growth behind the former. 
Passerculus sandwichensis savanna. Savannah Sparrow. My 
notes contain a record of this sparrow on October 25, 1925. The 
first definite record for 1926 is April 16, when two were taken 
in the ground trap on the Main Subdivision The first songs 
were heard April 22. Others were taken in the trap May 3, 6, 
9,13, 26. This little sparrow was numerous in the area through- 
out the entire season and was noted daily until July 21 (the last 
regular visit to the region). Songs were frequent until June 18, 
when there was a noticeable letting off probably coincident with 
the hatching of the young. However, singing was maintained 
until the middle of July. The census of mid-June showed nine 
breeding pairs. 
No nests were located in Evanston in spite of the large num- 
ber of breeding birds but the birds preferred the tall heavy 
quack grass (Agropyron repens) and, later, the red-top grass 
(Agrostis palustris). A nest, located at Ithaca, New York, was 
in tall grass of mixed Agropyron repens and Dactylis glome- 
rata (orchard grass) so dense that long searching was necessary 
to find it even though the bird flushed at my very feet. 
