48 Trans. Acad. Sci. of St. Louis 
things: eyes, light, clouds, time of day. In morning or evening, 
on clear days, it was always possible to find or to follow the 
bird with the unaided eye for the light, low in east or west, 
then does not blind the eyes and aids by giving the bird a 
shadow on one side or the other. With the sun nearly overhead 
the bird goes out of sight quickly for the light blinds and the 
size of the bird is not accentuated by a side shadow. With clouds 
above, of any description, a singing Lark can always be found 
for then it is a moving silhouette nearly always sharply outlined 
against its background. Under any circumstances the singing 
bird was always visible to an eight-power binocular if it were 
followed as it ascended so that its position could be ascertained. 
The songs, whose heights were obtained, were listed by months 
to see if the bird averaged higher or lower in one part of the 
season than in another. Nothing is evident, however, in the 
material at hand for, though the record height was in March, 
songs nearly as high occurred in June. Differences in heights 
then were matters of individual variation or the result of 
weather conditions. 
Duration of the flight songs.—Thirty-two songs were timed 
with a watch from the beginning of the ascent to the final drop. 
One minute was the shortest of which there were four; five 
minutes was the longest of which there were five. The average 
for all is 2.34 minutes. 
es Number of songs per minute during the flight.—Since the 
recitative’’ is a continuous jargon of notes its repetitions could 
not be timed. Its duration in a flight was rarely more than five 
seconds. The ‘‘intermittents’’, that is, the songs given while the 
bird is sailing, are repeated at remarkably regular intervals. 
The average number of these per minute, in an extensive series 
of counts, is 11.9. 
Relation of the singing male to the incubating female.— 
Mouseley (1919) gives the distance from the nest at which 
the male Lark sings (when on the ground), at 32, 34 and 21 
yards for three different nests. His figures are a bit too con- 
Servative, even for averages, for the Larks at Evanston or at 
Ithaca. By referring to Table 15 it will be noted that the male, 
in this case, preferred a song post at 50 yards, sang as far as 
100 yards from the nest, averaged 38.66 yards. Ithaca birds, 
