304 BULLETIN 17 0, UNITED STATES NATIONAL MUSEUM 



and the hind quarters of an American bittern. The old owls were in 

 attendance, but not on the nest. On April 26 the young were fully 

 half-grown and were about three weeks old ; their eyes were now light 

 yellow, and their primaries were bursting the sheaths. The nest con- 

 tained the remains of a skunk and a cottontail rabbit, and on the 

 ground below it were numerous black-duck feathers. The young now 

 showed fight, bristling up their downy plumage, spreading their 

 wings, snapping their bills, and threatening to attack. 



My last visit to the nest was on May 5, when only one young re- 

 mained in the nest; the other was soon discovered, sitting on a fallen 

 tree about 30 yards away. The young birds were much larger than 

 when I last saw them, being more than four weeks old and nearly 

 fully grown; their backs and wings were more fully feathered, and 

 their tails were well started, but the rest of their plumage was mostly 

 downy (pi. 74). The old owls were very solicitous and were keeping 

 a close watch over their helpless young; but, in spite of their protests, 

 I carried off one of the youngsters for future study in captivity. I 

 placed him in a roomy outdoor cage, with a sheltered compartment, 

 where he lived in apparent contentment for more than two years, 

 and might have lived longer if he had not been convicted of murder 

 and executed. During the latter half of June his wings and tail be- 

 came sufficiently developed for flight, though his body plumage was 

 still principally downy. In July, he could fly, but it was not until 

 October that he was fully feathered. 



The whole nesting period for this species is much prolonged; the 

 period of incubation has been estimated as from 26 to 30 days, but it 

 does not seem to have been accurately determined; Professor Keyes 

 (1911) says that it is not less than 30 days, and probably more. Both 

 sexes assist in it, but I suspect that the female does most of it. The 

 young do not open their eyes for the first week or ten days; they are 

 brooded by their parents for three or four weeks, perhaps more; they 

 do not leave the nest normally until they are four or five weeks old; 

 and they cannot fly until they are nine or ten weeks old. During all 

 this time they are watched, protected, and fed by their parents. Be- 

 yond this they follow the old birds about, crying lustily for food, per- 

 haps for many weeks, until they learn to hunt for themselves and are 

 finally driven away, thoroughly weaned, to other hunting grounds far 

 from the place of their nativity. Dr. Paul L. Errington (1932a) 

 writes: "Where does the juvenile go, after it takes up a wholly inde- 

 pendent existence? Of thirteen horned owl nestlings (birds that had 

 never been tamed, tethered, or experimented with in any way to re- 

 duce their prospects for survival) personally banded in 1930 and 1931, 

 three were reported shot within a year or so, all at points thirteen to 

 twenty miles of where banded." 



