April 1, 1904.] 



SCIENCE. 



553 



next morning. On June 3 the chipping spar- 

 row again left the nest, and I did not return 

 him to the structure until late in the day. 

 On the fourth, the two young canaries and the 

 chipping sparrow all left the nest, though the 

 canaries resorted to it from time to time. All 

 the birds grew and flourished, but on the ninth 

 of June the chipping sparrow died. The 

 two canary birds, however, throve and ulti- 

 mately reached maturity. During the latter 

 part of his life the sparrow was going about 

 the bottom of the cage and hopping on the 

 perches, attended to carefully by the parent 

 birds. He, however, did not seem especially 

 strong in his legs, and for a short period, four 

 or five hours before his death, he was not only 

 unable to grasp the perches, but could not 

 run about the bottom of the cage as he had 

 done earlier. I concluded that several fac- 

 tors may have militated against the rearing 

 of this bird by the canaries : (1) His develop- 

 ment seemed more rapid than that of the 

 young canaries, and he was more restless and 

 aiLxious to leave the nest than were the do- 

 mesticated birds. (2) I think that the arti- 

 ficial lining of the canary's nest was of such 

 a nature as not to permit the proper develop- 

 ment of the leg muscles and feet during the 

 time he was in the nest. (3) The length of 

 the tarsus in the sparrow, being twice as great 

 as that of the canary birds, seems an important 

 element to take into account, as this part of 

 the leg was so long that it seemed to be not 

 only in his way, but was constantly trodden 

 on and sat upon by his two associates. It 

 must be remembered that this bird left the 

 nest voluntarily on the date first mentioned, 

 and though restored several times, very soon 

 left it again. He appeared to be very un- 

 comfortable in the nest, and this discomfort 

 was largely due to the length of his legs. At 

 the time of his death the bird was about two 

 thirds grown, and almost fully feathered in 

 the first phunage of the chipping sparrow 

 (Spizella socialis) ; though he could hop aboiit 

 the floor of the cage, andfor a time was able 

 even to balance himself on the perches, his 

 legs, on the whole, seemed weak, and I at- 

 tribute the cause of this misdevelopment of 

 the muscles and tendons of the feet and legs 



to the kind of nest lining used by the canaries. 

 I may say here that this consisted of deer-hair 

 with an admixture of cow-hair, the whole be- 

 ing a felted mass, and not presenting the 

 grasping surface afforded by the fabric and 

 lining of the chipping sparrow's nest, as found 

 out of doors. 



My experiments in the season of 1902 in- 

 cluded, besides the above, an additional brood 

 of song sparrows, which contained four song 

 sparrow's and one cowbird's egg. All of these 

 hatched and lived from periods varying from 

 four to seven days, none of the birds leaving 

 the nest. I also experimented with a clutch 

 of five fresh eggs of the yellow-winged spar- 

 row {Ammodramus savannarum passerinus), 

 which I divided between two different parent 

 canaries, leaving two canary's eggs with three 

 yellow-winged sparrow's eggs, and in the other 

 case two yellow-winged sparrow's eggs with 

 thi'ee canary bird's eggs. Both clutches were 

 hatched, there being five young birds in each 

 nest. The canary birds in both cases were 

 reared and reached maturity, but the young 

 yellow-winged sparrows which were also 

 hatched died at ages varying from four to 

 seven days. 



I also attempted during this season to raise 

 young bobolinlis under canaries (Dolichonyx 

 oryzivorus) ; to this end on May 28, having 

 found a nest of five eggs, I introduced two 

 of them to a large breed of English canary, 

 leaving two of her own eggs in the nest; the 

 other three bobolink's eggs I placed under 

 another canary of a similar kind, leaving two 

 canary eggs in addition. This canary threw 

 out her own eggs, but retained the bobolink's 

 eggs, and incubated them till they were 

 hatched, which was on June 8. The three 

 young bobolinks lived for three days, when one 

 of them died; the remaining ones died on the 

 fifth day. The other bobolink's eggs, under 

 the English canary, were also hatched on the 

 eighth, but both died on the tenth of the 

 month; the young canary birds hatched at 

 the same time were reared to maturity, when 

 1 no longer followed their history. 



In the spring of 1903 I tried several similar 

 experiments, sometimes putting but one egg 

 of a wild bird with a clutch of canary's eggs. 



