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THE CONDOR 



Vol. IX 



on the ground, this owl begins preparation for its nest building, which, by the way, 

 is simple in the extreme. The month of April is the usual time for fresh eggs; and 

 to be more precise than this as to date is hardly possible, as I have found fresh eggs 

 as common during the first week of April as the last, and I am led to believe that 

 the nesting date is governed largely by climatic conditions. Moreover, the nesting 

 season is not confined to the month of April by any means, and nests with eggs 

 have been found as late as the 30th of May. This is, however, an extreme date and 

 is undoubtedly the result of an accident of some kind. 



As has been stated before 

 the nesting site is invariably 

 along the well wooded water- 

 courses and in more or less 

 dense groves of cottonwoods 

 and occasionally willow or 

 box-elder. A peculiar char- 

 acteristic of this bird is its 

 predilection for sluggish or 

 stagnant water, and one of 

 the prerequisites of a model 

 nesting site is a small slough 

 or pool within a short dis- 

 tance of the nest hole. I am 

 at a loss to know why this is 

 so, unless it is that frogs and 

 crawfish form no inconsider- 

 able portion of the bird's food, 

 and close proximity to a 

 source of food supply may be 

 a solution of the problem. 



The very great majority of 

 nests are found in cottonwood 

 trees. This is probably due 

 to the fact that this tree 

 greatly predominates along all 

 the foothill streams, and it is 

 the variety most commonly 

 used by the Red-shafted 

 Flicker, the deserted excava- 

 tions of which the Screech 

 Owl nearly always occupies. 

 However, natural cavities are 

 occasionally resorted to; but 

 owing to the nature of the 

 trees these are found mostly 

 in box-elder or black willows, the cottonwood rarely rotting out in this manner. 

 Captain Bendire in his incomparable work on North American Birds, states that 

 the birds occasionally lay in the deserted nests of the Magpie. 



The size of the cavities and entrances to the same naturally vary greatly. The 

 Screech Owls do not excavate at all, but simply preempt the cavities as they are. 

 It is extremely rare, however, that a nest is found in a cavity which is exposed to 

 the elements, great care evidently being used to select a cavity which is more or less 



HOME OF ROCKY MOUNTAIN SCREECH OWL; 

 AWAY TO SHOW NEST CAVITY 



WALL CUT 



