84 INSTINCTIVE BEHAVIOUR 
duction—there is much detail concerning which we are 
ignorant. But for our present purpose the important point to 
notice is that the procedure of the female cannot be due to 
imitation ; nor can it be the outcome of individually acquired 
experience ; for the method of procedure is not gradually 
learnt, but is carried out without apparent hesitation the first 
and only time the appropriate occasion presents itself. Not 
only does the moth take no heed of her grubs, but they are so 
placed that she could not in any case ascertain by observation 
that only if the ovules are fertilized do her offspring thrive. 
She cannot possibly know what effect the stuffing of the pollen 
on to the stigma exercises, or indeed whether it have any effect 
at all. And yet generation after generation these moths collect 
the pollen from the anthers and bear it to the stigma. Spence’s 
words “without knowledge of the end in view” are amply 
justified in this case, as in other cases of typically. instinctive 
behaviour. 
JII.—Tue Instinctive BrHAviour oF Youne Brrps 
Since it is easy to hatch birds of many species in an 
incubator, and to rear them under conditions which not only 
afford facilities for observation but exclude parental in- 
fluence, their study has special advantages. One can with 
some approach to accuracy distinguish the instinctive from 
the acquired factors in their behaviour.* 
The callow young of such birds as pigeons, jays, and 
thrushes are hatched in a helpless condition, and require 
constant and assiduous ministration to their elementary 
organic needs. Most of their instincts are of the deferred 
type. But pheasants, plovers, moor-hens, domestic chicks, 
and ducklings, with many others, are active soon after birth, 
and exhibit powers of complex co-ordination, with little or 
no practice of the necessary limb-movements. They walk 
* Some of the observations on which the summary of results given in 
this section are founded are presented in some detail in “Habit and 
Instinct,” pp. 29-100. 
