INSTINCTIVE BEHAVIOUR OF YOUNG BIRDS 93 
that of the chick, are early differentiated. The complaining 
note of the partridge is uttered six or seven times in quick 
succession, followed by a pause. The note of the plover is 
high-pitched, and much like the familiar cry of the adult bird, 
to which it owes its popular name of “ peewit.” So, too, the 
guinea-fowl in down utters from the first notes quite charac- 
teristic of its kind, while its danger-note is not unlike that of 
the chick or pheasant. The piping of ducklings is compara- 
tively nronotonous, and there does not seem to be a definite 
danger-note. With moor-hen chicks, even on the first day, 
two notes are well-marked—a call-note, lower in pitch than 
that of the chick, and rather harsh and raucous, and a “tweet, 
tweet” of pleasure, something like the contented note of a 
canary. Later, five or six notes are differentiated, the most 
characteristic of which is the harsh “crek, crek,” when the little 
bird is from any cause excited. It is uttered in a crouching 
attitude, with head thrown back and wings held outwards and 
forwards, waving to and fro in a very characteristic manner. 
That this has suggestive value for other moor-hen chicks is 
shown by its distinctly infectious effect ; if one bird has cause 
to utter the note and strike the attitude others follow suit. 
While clearly instinctive in their mode of occurrence, while 
they seem to show well the co-operation of an internal emo- 
tional factor, their biological value seems to lie in their sug- 
gestive effect on other members of the brood. They form an 
elementary but sufficient social bond. 
If these notes afford evidence of an incipient social factor, 
the instinct of pecking is distinctively individualistic. Chicks 
peck with considerable but not complete accuracy of aim at 
practically anything of suitable size at suitable distance ; but 
it is through experience that they learn what to select for food 
and what to reject or leave untouched. Moving objects, how- 
ever, are more readily pecked at than those which are still ; 
and the instinctive response seems to be stimulated if one tap 
on the ground near the object, or move it with a pencil, thus 
simulating the action of the hen. And this is even more 
marked with pheasants and partridges. Plovers seize small 
