46 Trans. Acad. Sci. of St. Louis 
song is to inform the other male of preempted territory and 
female ears are of little concern to the chorister. 
One thing of more than unusual interest was noted in respect 
to the frequency of flight songs, viz., that never were two birds 
in the air at the same time. No matter how many males were 
in the vicinity the one in flight song had exclusive privileges 
over a wide territory, undisputed, though another might go up 
as soon as the one in flight came down. Flight song territory is 
thus much larger than the surface territory ; territory boundaries 
are not vertical for any great height. 
As has been noted, singing from the ground was a fairly con- 
sistent performance through the day though perhaps a bit more 
frequent in the late afternoon. This day-time song from the 
ground was usually the ‘‘intermittent’’ type. But after sun- 
down, in June at least, the Larks had a vesper service which was 
almost exclusively ‘‘recitative’’. At that time, as the stars came 
on, they sang ‘‘pit-wit, wesspik pit-wee, wee-pit” on and on, 
minute after minute, pausing only now and then for breath or a 
moment’s intermission by singing ‘‘pittle, wittle, little lee’’. 
Quantitative studies of song.—The height at which the flight 
song is delivered has been a matter of considerable speculation 
by several writers. Thus Eaton (1912) says ‘‘reaching a height 
of several hundred feet’’, Townsend (1920) ‘‘sometimes out of 
sight in the low-flying clouds’’, Merrill (1888), in describing 
the song of O. a. strigata, writes that, ‘‘The height at which they 
fly is so great that often they may be seen to poise and then to 
resume their circling flight before any sound reaches the ob- 
server.’’ This last estimation making the height between one- 
thousand and two-thousand feet, for the ‘‘intermittent’’ song oF 
length of time of sail in praticola is just short of two seconds. 
Sound travels 1090 feet per second. This is, of course, an impos- 
sibility for at 1000 feet the Lark is invisible even to eight-power 
ag Patch, Bailey and others mention that they fly out 
0. < 
I attempted to secure an accurate measure of the height at 
which the song was delivered in order to settle the matter defin- 
itely. Three methods were employed: (1) by timing the drop 
with a stop-watch, (2) by using a large quadrant to secure a tri- 
angulation, (3) by measuring the length of the bird in the ait 
