130 
F. M. CAMPBELL-ON INSTINCT. 
intentional purpose. Naturally sucli birds would raise a greater 
number of offspring, who would inherit the tendency to perform 
the same device when they become mothers. Thus an original 
action “would slowly become organised into an instinct.” 
It seems to me that these practices of protection may have been 
otherwise developed. In the first place, the wings of a bird are 
ever concerned with the warmth and protection of its young, and 
their movements are therefore closely related to all the emotions of 
parent-hood. When a bird is flushed from her nest, or away from 
her young, she is under the influence of two powerful conflicting 
impulses, viz. anxiety for her progeny and self-protection. Darwin 
states, as a principle of serviceable associated habits:*' “Certain 
complex actions are of direct or indirect service under certain states 
of the mind, in order to relieve or gratify certain sensations, desires, 
etc., and whenever the same state of mind is induced, however 
feebly, there is a tendency through the force of habit and association 
for the same movements to be performed, though they may not be 
then of the least use.” Thus, movements which owe their origin 
to, and are frequently performed by an individual under the in¬ 
fluence of an emotion, become repeated when the emotion is roused, 
even though they may be objectless. A man who is angry with 
another a thousand miles away will close his hand and shake his 
fist, and it is scarcely too much to expect that a bird just driven away 
from her offspring should droop her wing towards the position it 
usually occupies when protecting them. Such action naturally 
disturbs her flight, and she falls as if wounded, when as her pursuer 
gains on her the conflicting desire of self-protection re-asserts itself, 
and she rises, when again the maternal instinct prevails, and the 
drooping wing follows. These alternations are repeated until she 
observes her nest, or the place where she left her young, free from 
danger, when she returns there. It may be asked, How is it, then, 
that this feigning of injury does not occur with all birds, or at least 
with all the individuals of the species in which this device is 
observed, for there are exceptions even among partridges, peewits, 
and ducks ? The answer appears to be that those birds in which 
the practice more frequently obtains build their nests on the ground, 
which is therefore more exposed to accidental intruders, so that 
the wings would be more constantly used for the purpose of passive 
and active protection, both as regards the eggs, and also the young 
when hatched. The “feigning injury” would be encouraged by 
stiffness if the bird had not flown for some time, but it would not 
occur if the desire of self-protection were considerably stronger than 
that of the protection of the young. That there are variations in 
the degree of parental instincts not only in species, but also in 
individuals of the same species, is a fact of which there is abundant 
evidence. 
Mr. A. E. Buxton informs me that he has seen a water-wagtail 
“ feigning injury ” in the happiest manner, and it would therefore 
* ‘ Expressions of the Emotions,’ p. 28. 
