Some Habits and Instincts of Young Birds. 31 



quoted, but in some cases their accuracy has not been 

 confirmed by later observers. 



The eggs from which the subjects of my own investiga- 

 tion were hatched were either artificially incubated from 

 the first, or were transferred from the hen to the incubator 

 a few days before they were timed to emerge, so that in no 

 case was the behaviour of the young influenced by older 

 birds. They were kept under observation in a small pen 

 or enclosure surrounded by wire netting, or in a room set 

 aside for that purpose, and were occasionally allowed the 

 run of a little garden plot. 



Previous to hatching, the little fellows may often be 

 heard chirping within the egg. Young moorhens do so 

 in some cases for as much as forty-eight hours, and 

 ducklings as much as twenty-four hours before they 

 finally emerge, and this in the case of strong and 

 healthy birds. The beak must then have pierced the 

 air-chamber within the egg, and direct air-breathing 

 must have taken the place of embryonic respiration. 

 The eggshell, when they thus begin to chirp within it, 

 is generally, but not always, broken or chipped at one 

 point of its surface. This chirping is a truly congenital 

 activity, and has not to be learnt. One young moorhen, 

 lying silent in the chipped shell, responded by chirping 

 to my low whistle. So that even then they can hear, 

 or at any rate are influenced by an auditory stimulus. 

 Mr. Hudson, referring to u several species in three widely 

 separated orders," tells us* that, according to his observa- 

 tions, "when the little prisoner is hammering at its shell, 

 and uttering its feeble peep, as if begging to be let out, 

 if the warning note is uttered, even at a considerable 

 distance, the strokes and complaining instantly cease, and 

 the chick will then remain quiescent in the shell for a 



* "Naturalist in La Plata," 1892, p. 90. 



