132 Trans. Acad. Sci. of St. Louis 
quiet, mild days; perhaps a little more numerous when the sky 
is overcast than when it is clear. 
3. Variations in song through a nesting period. Most vigorous 
period of song extended through nest building, egg laying and 
incubation. Perhaps of this period that portion of it when the 
female incubated allowed most song from the male since he 
attends the female carefully during nest building and egg lay- 
ing. Period of least song occurs when young are in the nest, 
for the male assists in feeding. 
4. Variations in song throughout a day. Ground songs are 
regularly distributed throughout the entire day; flight songs 
seem to be most numerous toward noon and near sundown. 
5. The relation of the song of the Lark to that of other birds. 
For three months the Prairie Horned Lark is the only singing 
bird in the open field; with the coming and establishment of 
other migrants in late May and June many other songs will be 
heard in that region. On June 16, 1926, the Horned Lark, the 
last to begin song, went into flight song at 4:00 A. M. The Lark, 
however, almost always closed the singing at night with a long 
period of recitative which in mid-June, would not close until 
after 8:00 P. M. 
6. Description of song. The literature contains several de- 
scriptions of the flight song of the Prairie Horned Lark, that 
of Langille (1892) seeming to be most accurate. He describes 
the flight. The song he describes as ‘‘quit, quit, quit, you silly 
rig and get away’’. This is the intermittent type; nowhere in 
the literature has a description of the recitative been found. 
7. Types of song. Songs are sung from the ground, from 4 
clod or any other slight elevation, the greatest elevation being 
the roof of a sample apartment put up on the Evanston area; 
and from the air. The ground gongs are similar to the flight 
songs though rarely as long or as systematically presented. 
: The urge to flight song may come at any time or after aD 
invading male Lark has been evicted from occupied territory. 
Larks will also go into flight song upon the approach of a human 
or they can be forced to go up by driving them for a time about 
their territory. 
‘The climb to flight song is distinctive and usually executed 
without a sound from the bird. The songs, in the air, are of 
two types: a recitative or rapid monotony of notes usually 
