Reproduction 91 
ing female. The male, beyond occasional call notes, showed 
little or no solicitude while eggs were in the nest. 
To see if these two reactions, ‘‘casual abandonment’’ and 
“‘distress simulation’’, could be reduced to a formula I spent the 
greater portion of one day flushing an incubating female from 
her nest. The results are given in Table 14. Let me add that, 
in spite of this evil treatment, the eggs hatched in normal time, 
the young prospered until found by a weasel or other enemy. 
Moreover, I have tabulated the recorded reactions for every visit 
to incubating females both at Evanston and at Ithaca. These 
results are given in Tables 10 and 12. The ‘‘other reactions’’ 
here include intermediate types chiefly. Thus it will be seen 
that, though the first effort of a female Lark to protect her nest 
is to attempt to deceive the searcher by an unconcerned flight 
(the ‘‘casual abandonment’’), this highly developed instinct is 
inhibited by various conditions (such as flushing at too close 
intervals), and then the more primitive instinct, that of distress 
simulation, gradually takes its place. In many respects these 
reactions resemble those of the Killdeer (see Pickwell, ‘‘ Nesting 
of the Killdeer’’, Auk 42, 1925, pp. 490-491). 
It has been my intention since beginning work with the Prairie 
Horned Lark to see if the above reactions would be given for 
animals other than man and if they were the same (or different), 
to speculate upon the reasons. No opportunity has as yet pre- 
sented itself for this type of experimentation but two accounts 
in the literature give a clew. Brooks (1908) writes that adult 
Larks at French Creek, West Virginia, alighted on the backs of 
chickens to drive them away from the nest. Criddle (1920), 
also remarks that the female Lark would fly at a hen with such 
vigor as to cause her to become seriously alarmed and to make 
her leave in a hurry. Criddle also makes the important obser- 
vation that before dogs and man the female slipped quietly from 
her nest. This last was, apparently, a typical abandonment con- 
cealment. It appears, then, that the Lark does not reserve a 
Special reaction for man alone but can, however, distinguish 
between mammals and large birds and has distinct reactions for 
each 
The Young 
Hatching —Of hatching there is but little to say. In spite 
of daily visits only once did I arrive during hatching, once only 
