on Instinct in Song Birds . Breeding in Hand-reared Robins. 275


were destroyed by other birds whenever an opportunity was

given.


It is rather difficult in such a heterogeneous company to

determine exactly what transpires; but this is about the case :

They do not attempt to build any cnp of mud in such a nest as I

have indicated, but the particular pair of Robins in question did

not put a mud floor in the basket. I was unable to see them feed

or take care of the very small young Robin which I observed in

their nest and which was their own progeny, during its early

infancy ; but when I substituted the foster-children, as I may call

them, that were older than the young bird, all the operations of

feeding and taking care of the young were apparent. The female

bird brooded the young ones for periods of from fifteen minutes

to au hour,while the male bird constantly brought her food for the

young. He also removed all excrement as it was evacuated and

carried it at least ten feet away from the nest, and generally

farther. Twice I saw him eat the excrement after he had laid

it on the floor. I have watched Robins carefully out of doors ;

and so far as I am able to judge, these Robins in captivity went

through all of the actions and attained all the results that Robins

attain with broods out of doors. It is not a little singular that

they neglected, or that I fancied they neglected, to take care of

one of the young ones, and that their attention was entirely

concentrated 011 a single bird. All of these actions that I have

recorded must have been instincts awakened by the various

stimuli which precede instinctive acts, for no education by

imitating the acts of older birds was possible.


It is also interesting in this connection to record the fact

that another pair of Robins breeding, or attempting to breed,

under similar conditions, so far as I know have failed to lay eggs,

or their eggs have been stolen by other birds after they were

laid. However, the female parent is incubating and is fully as

4 broody ’ as any hen would be under like circumstances. That is,

I may go up to the nest where she sits, and it is absolutely

necessary for me to take her from the nest by force if I wish to

see what is beneath her. At such times she bites my finger and

fights, and when removed from the nest, utters all the alarm cries

and notes that a bird out of doors does when disturbed.



