222 BULLETIN 17 0, UNITED STATES NATIONAL MUSEUM 



seen about the nest, but during the night the female was taken in a 

 trap placed on a pole near by for that purpose." 



Two recently found nests are described by A. G. Lawrence (1932). 

 One of them, containing five young, was discovered on May 7, 1932, 

 by Alex Mackie near Winnipeg, in a hole 18 feet from the ground in a 

 dead poplar stump in open woodland country. The other nest, with 

 five eggs, was discovered by V. Latta at Shelley, Manitoba, on May 

 15, 1932, in a spruce muskeg in a "woodpecker's hole about 18 feet 

 from the ground in a dead tamarac stub, the eggs being placed in a 

 thick bed of wood and bark chips, mixed with some owl feathers." 



While the Richardson's owl is well known to nest in holes in trees, 

 holes generally made by the larger woodpeckers, or in natural cavities, 

 it has been stated that it also nests in the deserted open nests of such 

 birds as the gray-cheeked thrush or the rusty blackbird, or in nests 

 made by the owls themselves. This is said to be the case in the north 

 where there are no large trees, but merely stunted trees and bushes. 

 Nelson (1887) and Dall reported eggs brought to them from such 

 nests by fur traders and Indians, but considerable doubt exists as to 

 the accuracy of the testimony of these natives. Bendire (1892), who 

 quotes these records, states that the eggs obtained by Nelson are 

 unquestionably those of the American hawk owl. 



Eggs.- — [Author's note: The number of eggs laid by Richardson's 

 owl varies from three to se\en, but usually the set consists of four, 

 five, or six. They are pure white and oval; the shell is smooth, with 

 very little gloss. The measurements of 47 eggs average 32.3 by 2G.9 

 millimeters; the eggs showing the four extremes measure 36.5 by 27.1, 

 35.3 by 28, 28.8 by 27, and 30 by 25 millimeters.] 



Young. — The duration of incubation is not known but is probably 

 about three weeks. As the parents begin to incubate soon after the 

 first egg is laid and egg-laying may take 8 to 12 days, it is evident that 

 the young in the nest will vary much in size. A. G. Lawrence (1932) 

 says of five young found in a nesting hole that they "ranged in size 

 from a baby a few days old, clothed mainly in white down with the 

 dark brown feathers appearing on the upper parts, to a well feathered 

 youngster which had lost most of its downy feather tips, and was 

 probably two weeks old." 



Plumages. — [Author's note: I have not seen the downy young of 

 Richardson's owl, but infer from the above statement that it is covered 

 with white down, though Witherby's Handbook (1924) states that in 

 the closely related Tengmalm's owl the "down is huffish-white on 

 upper-parts and white on under-parts." We have no data on the exact 

 age at which the ju venal plumage is acquired, but, if Mr. Lawrence's 

 (1932) estimate is correct, it must be quite completed within three 

 weeks. The juvenal plumage is sufficiently unlike that of the saw- 

 whet owl to be easily recognized. The entire upper parts are clear, 



