88 Trans. Acad. Sci. of St. Louts 
nests and always it has been the female. A full day spent at 
one nest (Table 15), failed to show the male in any inclination 
to incubate. Similarly a full day at a nest with young (Table 
17) failed to show that the male broods. 
Reactions of female and male Larks during incubation pe- 
riod.—The reactions of the incubating female express some of 
the most highly-developed nest-protective instincts among birds. 
She has two such instincts with a series between these two. The 
first, and most highly developed, is a reaction I have called 
Reactions of the Prairie Horned Larks to man when young were in the 
nest, at ft N. Y., 1927, 
No. of Times } No. of Casual Ino. of Distress i of Other 
Nest No. No. of Visits [Parents Noted |Abandonments| Simulations actions 
Aa 9 3 1 0 2 
Bi 4 4 0 1 3 
B: 30 16 4 9 3 
Ba 8 6 0 1 5 
Ci 30 11 4 0 7 
he sic 8 ies 
Total oc. 81 40 9 11 20 
Ma ae aig Neve cntece ehm 
the ‘‘casual-abandonment’’. Typically expressed it consists of 
an abandonment of the eggs while an intruder is from one-hun- 
dred to twenty-five yards distant. The female leaves without 4 
sound (usually flying directly from the nest in spite of frequent 
remarks in the literature to the contrary), flies low against the 
ground like a grey wraith and is soon lost to sight. Her flight 
under such circumstances is unique and distinct, most frequently 
without marked undulation, with steady wing beat with a pause 
of time of about one beat between each beat. So highly devel- 
oped is this method of nest protection that the female leaves the 
nest at a greater distance than a timid Lark would fiush under 
other circumstances. Other writers describe this reaction though 
make no attempt to explain it. Thus Merrill (1888) in writing 
of O. a. strigata says: ‘‘The male, who is constantly on the watch, 
seems to call the female off the nest when an intruder is still at 
a distance; several times I saw one approaching her mate, shak- 
