386 LIFE HISTORIES OF NORTH AMERICAN BIRDS. 



birds not yet able to fly are occasionally found so late in the season, and some- 

 times in localities where they certainly had not been disturbed previously, it 

 would appear as if a second might now and then be reared. A few days after 

 my arrival at Fort Klamath, Oregon (June 18, 1882), one of my men brought 

 me a young Owl of this subspecies which he had caught alive in the pine 

 forest south of the post. It could barely fly at the time, and if not from a 

 second bi'ood the eggs must have been laid several weeks later tlian usual. 



The eggs number two or tlu-ee to a set, occasionally four, and sets of 

 three are about as often fiund as the smaller number, while those of four 

 are not especially rare. Mr. Charles F. Morrison reports taking one of six 

 in Wvoming, an extremely large set, and Mr. Charles C. Neale writes me 

 that he took a set of five eggs from a nest in an oak tree in the mountains 

 in Plumas County, California. 



Tliey are deposited generally at intervals of two or three days, the 

 female attending to the duty of incubation exclusively, I believe, and wliich 

 lasts about foiu- weeks. The male supplies his mate with the necessary food 

 while she is so engaged, and when not liunting is usually found in close 

 pi-oximity to the nest. The eggs are similar to those of the Great Horned 



Owl. 



The average, measurement of fifteen specimens in the U. S. National 

 Museum collection is 55.5 by 47 millimetres. The largest egg of this series 

 measures 58.5 by 48.5, the smallest 53.5 by 45 millimetres. None are figured. 



135. Bubo virginianus arcticus (Swainson). 



AKCTIC HORNED OWL. 



Strix (Bubo) ardica Swainson, Fauna Boreali Americana, 11, 1.S.'51, 80, PL 30. 

 Bubo virginianus var. arcticus Cassin, Ilhistrated Birds of CaUfornia, etc., 1854, 178. 

 (B 48, part ; C .317o, part ; R 4056, C 463, part; U 3756.) 



Geogr.^phical range : Arctic America, chiefly the interior ; south in winter to 

 the Great Plains (the two Dakotas, Montana, etc.). 



The breeding range of the Arctic Horned Owl, a much lighter colored 

 race than the two preceding forms, is confined, as far as known at present, 

 to those parts of the interior of British North America situated between James 

 Bay (Moose Factory), the west shores of Hudson Bay, and the eastern slopes 

 of the Rocky Mountains, north of latitude 51°, and extending in a northwest- 

 erly direction to northern Alaska, wliere a specimen was obtained bv Mr. C. L. 

 Mackay on the Attokuagik River, August 24, 1881. Like the Western Horned 

 Owl it inhabits the more open country ihrciughout its range, more especially 

 along the shores of the numerous lakes and streams found in those inliospi- 

 table regions. In winter it migrates soutliward, though rarely entering our 

 borders. As yet I have not seen a specimen of this race obtained witliin the 

 limits of the United States that could be called tjijical. While stationed at 



