on Rearing Wild Finches by Foster-parent Birds. 359


them with two Canaries about the same size, though more fully

feathered. These birds were readily adopted by the parent

Canaries, but one of them died after three days; the other was

reared, reached maturity, was weaned by the old birds, being

treated precisely as were their own young, and is still alive at this

writing.


This series of experiments I have reported as a suggestion

for further work of a similar kind. I had hoped that hatching

the eggs of wild birds under Canaries would enable me to

observe the development of the foster-young to an advanced age.

It seemed to me that there would be no possibility of their song

being other than such as could be attributed either to inheritance

or to intimate association with a new kind of singing bird. In

all this I have, of course, met with disappointment ; the only

young bird being reared to maturity, from the many I have

tried, was a Song Sparrow, almost fledged before introduced to

his foster-parents. It has occurred to me that perhaps the kind

of food, partially digested by the parent Canary birds, and then

regurgitated and fed to their young, would have militated against

the growth and development of another kind of bird. How¬

ever, in the case of three Cowbird’s eggs upon which I have

experimented, all of which were hatched, this should not have

prejudiced their growth, when we consider the variety of foster-

parents that are induced to hatch and rear the eggs and j^ouug of

the Cowbird.


To briefly summarize the work I have described in some

detail, forty-one different eggs of wild birds, representing six

species, and three young birds already hatched, form the

aggregate of individuals dealt with. All of the forty-one eggs

were fertile, and were hatched by the foster-parents. This is

suggestive in regard to the propagating powers of wild birds,

and though not conclusive, indicates a much higher percentage

of fertility in the eggs laid by them than obtains in song birds

when caged, or semi-domesticated. None of the young which

were hatched from these eggs reached a greater age than seven

days, which would seem to indicate that the food supplied by the

foster-parents, which was the same on which they raised their

own offspring, was of a kind so different from that used by wild



