Summary 133 
uttered at the beginning of the flight song, though occasionally 
at other periods, never over a few seconds in duration, accom- 
panied by a steady beat of the wings; an intermittent uttered 
while the Lark sails, about two seconds in duration, followed 
by a somewhat longer silent period during which the Lark flut- 
ters up. The recitative can be transcribed as ‘‘pit-wit, wee-pit, 
pit-wee, wee-pit’’; the intermittent as ‘‘pit-wit, pit-wit, pittle 
wittle, little, little, leeeeee’’. Large rough circles are described 
overhead during the flight song or the bird heads into the wind 
if it is strong. The Lark closes flight song by a headlong drop 
to earth with wings tightly folded. 
Female Larks seem to. be unaware of the males in flight song 
though other males note the bird overhead. The territory which 
a bird may occupy in flight song is very extensive. Never were 
two visible birds noted in such a performance simultaneously. 
The one in the air is left undisturbed though his performance 
may carry him over many other Larks breeding grounds below. 
Breeding territories are not vertical for a distance above a few 
feet; the flight song territory is something quite different. 
8. Quantitative studies of song. 
a. Height of the Lark in flight song. Of several methods 
employed to determine the heights of Larks in flight song 
the most accurate was found to be the use of a binocular 
with an ocular scale. It was determined thus, through 
measurement of 25 songs, that the Lark sings from eleva- 
tions that vary from 270 to 810 feet. The average was 
464.4 feet. Differences in height seemed to be individual 
variations or due to weather. 
b. Duration of the flight song. Thirty timed flight songs 
varied from one minute to five; the average was 2.34 
minutes. 
¢. Number. of songs per minute during the flight. Inter- 
Mittents, regularly given, averaged 11.9 per minute. 
d. Relation of the singing male to the incubating female. 
An Evanston, Illinois, bird sang from song posts on the 
ground which, during one entire day, varied a few feet 
from the incubating female out to 100 yards. The average 
was 38.66 yards. Ithaca birds, with bigger territories, sang 
frequently as far as 150 yards from the nest. 
