826 POPULAR SCIENCE MONTHLY. 



Even after the youngsters have left the nest the mother cowbird 

 does not assume the care of them, but still leaves them in charge of 

 the foster parents. It is laughable, almost pathetic, to see a tiny 

 ovenbird or redstart feeding a strapping young cowbird which is 

 several times as large as herself. She looks like a pygmy feeding a 

 giant. In order to thrust a tidbit into his mouth she must often 

 stand on her tiptoes. Why the diminutive caterer does not see 

 through the fraud I can not say. She really seems to be attached 

 to the hulking youngster. By and by, however, when he grows 

 large enough to shift for himself, he deserts his little parents and 

 nurses and seeks companionship among his own blood kindred, who 

 will doubtless bring him up in the way all cowbirds should walk. 



It is surprising how many species are imposed on successfully by 

 the cowbird. The number, so far as has been observed, is ninety, 

 with probably more to be added. Among the birds most frequently 

 victimized are the phoabes, the song sparrows, the indigo birds, the 

 bush sparrows, and the yellow-breasted chats. Even the nests of 

 the red-headed woodpecker and the rock wrens are not exempt. 

 Some species, notably the summer warblers, detect the imposture 

 and set about defeating the purposes of the interloper. This they 

 do by building another story to their little cottage, leaving the ob- 

 truded eggs in the cellar, where they do not receive enough warmth 

 to develop the embryo. 



While it is surprising that acute birds should allow themselves 

 to be imposed on in this way, perhaps, after all, they look upon the 

 cowbird as a kind of blessing in disguise; at least, he may not be 

 an unmixed evil. They may act on the principle of reciprocity 

 that " one good turn deserves another." What I mean is this : In 

 my rambles I have often found the cowbirds the first to give warn- 

 ing of the approach of a supposed danger. Having no domestic 

 duties of their own, they can well secrete themselves in a tall tree 

 overlooking the entire premises, and thus play the useful role of 

 sentinel. This, I am disposed to believe, is one of the compensating 

 uses of this parasite, and may furnish the reason for his being toler- 

 ated in birdland. And he is tolerated. Has any one ever seen 

 other birds driving the cowbird away from their breeding precincts, 

 or charging him with desperate courage as they do the blue jays, 

 the hawks, the owls, and other predatory species? He evidently 

 subserves some useful purpose in the avian community, or he would 

 not be treated with so much consideration. 



A young cowbird that I purloined from the nest and reared by 

 hand did not prove a very pleasant pet. He was placed in a large 

 cage with several other kinds of young birds. At first he was quite 

 docile, taking his food from my hand and even allowing some of 



