HISTORY OF CERTAIN GREAT HORNED OWLS KEYES. 401 



one's cap, and quickly duck one's head as the great missile rushes 

 past. The owl keeps straight on her course and alights with heavy 

 impact on a branch of a neighboring tree. Here she faces about and 

 very likely comes straight back again. This process became finally 

 a bit too exciting and, after making certain that the headless quad- 

 ruped lying in the nest over behind the owlets was just a big house 

 rat, I slipped down the ladder and went home. 



February 7, 1907, was cold and clear after the terrific snowstorm 

 of the night before. On this day Mr. James R. Smith, a young farmer 

 of the vicinity who had always been interested in birds and who was 

 destined to be my skillful assistant throughout the season, accom- 

 panied me to the snow-covered timber pasture. As we approached 

 the nest tree of the year before a fox squirrel leaped from one of the 

 smaller adjacent trees and, starting up the big elm, ran along the 

 rim of the great knothole which formed the owls' doorway and 

 scampered onto a topmost branch. If the owl were at home the 

 saucy fellow surely passed within 10 inches of her face. For a moment 

 we felt dubious as to the nest being occupied. As we approached the 

 tree, however, a great horned owl flew from one of the higher branches, 

 aroused either by the squirrel or, more likely, by our own approach. 

 This was more favorable. We gave the tree a few kicks, when the 

 sitting bird hopped up lightly to the rim of the cavity, looked across 

 the white landscape for several seconds, then spread her nearly 5 

 feet of wings and flew silently away. 



Our first mistake for 1907 was in not looking into the nest on 

 this first day. Our reasons for not doing so were the belief that the 

 set of eggs could hardly be complete at this time and especially the 

 fear that the egg or eggs could not stand exposure even for a short 

 time on so cold a day. My present belief is that this fear was 

 unfounded. Just two da} 7 s later, on February 9, at about 3 o'clock 

 in the afternoon, I visited the nest again and found the set of three 

 eggs complete. These were lying in a slight hollow as before, but as 

 far back in the cavity as possible. Except for a small space about 

 the eggs the house was filled, even to the doorsill, with snow. It 

 was a picture, indeed, but one over which we did not dare tarry in 

 freezing weather. All the eggs were nest stained and it did not look 

 as if any one of them had been laid that day. However, this was 

 uncertain, and I had lost a possible opportunity of learning just when 

 the set became complete. This was regrettable, for no one seems to 

 know the period of incubation of an egg of the great horned owl. 

 The older ornithologists made their guess at 3 weeks. Bendire later 

 expresses his belief that this period is too short and that 4 weeks is 

 probably nearer to the truth. I have not determined the point, 

 though my data still possesses some interest. Toward the end of the 

 38734°— sm 1911 26 



