LIST AND DESCRIPTION 91 



According to the writers' observation the "gray phase" predom- 

 inates in South Dakota, while records from eastern Iowa seem 

 to show the reverse. 



The Screech Owl may be found at home along wooded 

 creeks in the most sparsely settled districts, or in resident por- 

 tions of our larger towns and cities. In the latter case they no 

 doubt help to keep down the increasing numbers of "pesky" 

 English sparrows. Their food consists chiefly of mice. They 

 should be encouraged to nest around buildings. Their weird, 

 wailing notes, heard at dusk or in early morning, have caused 

 some who are not acquainted with the call notes of these little 

 fellows to suspect that a strange wild cat was prowling in the 

 vicinity. 



373e. ROCKY MOUNTAIN SCREECH OWL (Otus asio maxwelliae.) 



Specimen taken in Fall River County, August 8, 1911, by 

 Stephen S. Visher and determined by H. C. Oberholser of 

 United States Biological Survey as this species. 



Resembles the common gray Screech Owl but paler; black 

 markings not so prominent. 



375. GREAT HORNED OWL (Bubo virginianus virginianus.) 



Common over the State and more or less resident. One 

 of our largest Owls, measuring up to twenty-two inches in length, 

 the female always larger. 



The Great Horned Owl is quite variable in color mark- 

 ings. Above their base the feathers are tawny, sometimes tawny 

 and gray, but more or less irregularly tipped with black and 

 white. Below, usually lighter, mixed with tawny, and occa- 

 sionally there are black spots on the breast and a white throat. 

 Tail barred with black; long ear tufts. 



They nest in hollow trees or nests used by Crows the 

 previous season. The eggs are laid as early as February or 

 March. On April 1, 1919, two weeks old young were taken from 

 an old Crow's nest near the Vermillion River in Clay County. 



Great Horned Owls catch and eat a variety of animals 

 ranging in size from small birds and mice to cottontail rabbits 

 or full grown poultry. In some instances they have been known 

 to kill more poultry than was necessary to satisfy their hunger. 

 This is probably true only of certain individuals, and a good way 



